## SCC Tools Download

The Scenarist Closed Caption Tools package is available for download here. The latest version is 3.5 (May 5, 2005), which affects three tools: CCADJ can now scale timecodes with the new `-m` argument; CCASDI fixed a lot of bugs, including a mistake in filler byte handling pointed out to me by correspondent Ji-Liang Song; and RAW2SCC will now handle multi-channel raw files better. For details, see the complete version history.

## SCC Tools Documentation

The SCC Tools package consists of ten command-line tools (and one General Parser module) designed to assist in the task of extracting, manipulating, and inserting the additional data included in Line 21 of NTSC video: closed captions, MSNTV links, V-Chip ratings, and a variety of lesser-used types of information.

The following files should have been included in this distribution:

- CCADJ.EXE: Command-line utility to adjust timestamps on SCC and Closed Caption Disassembly files.
- CCASDI.EXE: Command-line utility to convert between SCC and Closed Caption Disassembly formats. Also converts SCC to any of six subtitle formats.
- RAW2SCC.EXE: Command-line utility to convert raw closed caption data to SCC format.
- SCC_RIP.EXE: Command-line utility to extract raw and SCC closed caption data from MPEG files (supplanted by CCExtract below).
- DVR2SCC.EXE: Command-line utility to extract raw and SCC closed caption data from DVR-MS files.
- SCC2RAW.EXE: Command-line utility to convert SCC format to raw broadcast format.
- SUBRIP2SCC.EXE: Command-line utility to convert Subrip subtitles to SCC format.
- VOBSUB2SCC.EXE: Command-line utility to convert raw VobSub-created data to SCC format.
- PAS2SCC.EXE: Command-line utility to convert CCWriter (DOS) closed files to SCC format.
- CC_MUX.EXE: Command-line utility to incorporate closed captions into MPEG files.
- DOCS\SCC_TOOLS.HTML: Documentation for SCC Tools (this file).
- General Parser\projects\MPEG\video\CCExtract.gp: General Parser module file to rip raw closed caption data from MPEG files.
- General Parser\projects\MPEG\video\CCExtract_VES.gp: Another General Parser module file, for use on demuxed Video Elementary Stream files when CCExtract.gp doesn't work.
- General Parser\source\MPEG\CCExtract.bdl: General Parser source file to rip raw closed caption data from MPEG files.
- SAMPLES\*.*: Sample Closed Caption files, in various formats.
- SOURCE\*.PL: Perl source for SCC Tools.

For an explanation of Line 21 Closed Captions and how they are encoded, click here. For high-end DVD authoring (Sonic Scenarist, Apple DVDStudio Pro, and the discontinued Spruce DVDMaestro), closed captions are entered as files in the SCC format (for Scenarist Closed Caption). Since this format is not readable by humans, I have included tools to convert SCC format to CCD (Closed Caption Disassembly) format and back. The CCD Format is documented here (including additional pages on characters, Closed Caption codes, eXtended Data Service codes and Interactive TeleVision codes in Closed Caption Disassembly format).

### Topics:

Extracting Line 21 Data

- Capturing Raw Closed Caption Data from an Analog Source
- Getting Raw Closed Caption Data from a VCD
- Converting Raw Closed Caption Data to SCC Format: RAW2SCC
- Ripping SCC Captions from a DVD: VobSub and VOBSUB2SCC
- Extracting SCC Captions from MPEG files: General Parser and CCExtract
- Extracting SCC Captions from DVR-MS files: DVR2SCC
- Converting Subtitles into Closed Captions: SUBRIP2SCC
- Converting from other Closed Caption formats to SCC format: PAS2SCC

Manipulating Line 21 Data

- Converting SCC to a Readable Format: CCASDI
- The Closed Caption Disassembly Format (including additional pages on characters, Closed Caption codes, eXtended Data Service codes and Interactive TeleVision codes in Closed Caption Disassembly format)
- Adjusting Timecodes: CCADJ

Inserting Line 21 Data

- Inserting captions into MPEG files: CC_MUX
- Converting SCC Format to Raw Format: SCC2RAW

Capturing Raw Closed Caption Data from an Analog Source

To obtain closed captions, you can either write them from scratch in Closed Caption Disassembly Format, convert them from subtitles or other other closed caption formats, rip them from a DVD or MPEG or DVR-MS file, grab them from a VCD, or capture them with a TV capture card from an analog source. The last of these methods is the most involved, so it will be covered first.

To capture closed captions from a VCR, a laserdisc player, TV, or a settop DVD player, you will need a TV capture card. For the purposes of closed caption capture, the cheaper the card, the better, since the high-end cards usually throw away the Line 21 signal to improve performance. Any card with a WDM (Windows Driver Model) driver should work (see this site for a generic WDM driver for cards that use the Brooktree chip--if the box makes a big deal about "watching TV on your PC", then it probably uses a Brooktree chip). Unfortunately, the ATI-TV Wonder USB edition drivers are not WDM (and the main chip is not a Brooktree), so you cannot use this potentially-useful device. The most common card that does work is the ATI-TV Wonder PCI, available for less than $ 100. However, this card will not work on a Windows 2000 or Windows XP machine if your primary video card was not manufactured by ATI (NVidia cards in particular refuse to work with the ATI-TV Wonder in these two operating systems). Personally, I performed my research using an old computer with Windows 98 and the ATI-TV Wonder PCI to capture closed captions, then transferred the caption files to my main computer via floppy disk.

To capture the Line 21 data, you will be using GraphEdit, a tool that comes with the DirectX Software Development Kit, to put together a program for dumping closed captions to a file. You can download GraphEdit by itself from Doom 9, or from Microsoft as part of the DirectX SDK. The SDK (at 215+ MB a rather-large download) is probably worth loading for only two reasons: it already includes DirectX (in case you need to upgrade), and its help file is useful for figuring out what the different DirectShow filters do (in the Contents tab, look under DirectX - DirectShow - DirectShow Reference - DirectShow Filters). On the other hand, the Doom 9 version includes the Dump filter, which you will need in the below procedure.

The simplest way to set up your graph is to open GraphEdit and your TV watching program at the same time, get the second program up and working, then switch to GraphEdit and select "Connect to Remote Graph" from the File menu. This should give you all the interconnected parts needed to watch TV, and from here it you should be able to find the VBI pin on one of the filters (pins are represented in GraphEdit as bumps on the boxes, which are the filters).

Assuming this procedure worked and you found a VBI pin, select Insert Filters from the Graph menu. Under WDM Streaming Tee/Splitter Devices, insert the "Tee/Sink-to-Sink Converter" filter. Under WDM Streaming VBI Codecs, insert the "CC Decoder" filter. Under DirectShow Filters, insert the "Dump" filter (this will prompt you for a filename to dump to, so use "cc.bin").

You will see all of these filters on your graph, probably on top of each other. Spread them out, then connect them in sequence by dragging from an output pin (bump on right side) of one filter to an input pin (bump on left side) of another. Your goal is something like this (just pay attention to the VBI pin and the filters I've named--the rest doesn't apply as well; also, the blue box is the Dump filter, although that's not very obvious). One tweak you should be able to apply is selecting which line and field to capture (the default of Line 21 Field 1 for closed captions, Line 21 Field 2 for XDS, or other lines and fields to get something completely different)--right-clicking on the "CC" output pin of the CC Decoder filter should give you this option (I no longer have my Windows 98 computer with the ATI-TV Wonder PCI, so I have no way of confirming this anymore).

To start capturing captions, press the play button in GraphEdit. A preview window may or may not appear, and the captions probably won't be visible (unless you follow the steps below in the detailed procedure), so you'll have to trust that everything is working. Click the stop button in GraphEdit when you're done (don't close the preview window before you do this). Check to make sure the file created has something in it (it will be in binary format, so you won't be able to read it). If everything has worked up to this point, proceed to convert the file to SCC format.

Assuming that "Connect to Remote Graph" didn't work, the following procedure describes what to do in more detail (although if "Connect to Remote Graph" didn't work, that might mean that the capture card doesn't use the DirectShow architecture, which would mean there is no way to hijack it to capture closed captions--maybe you should return the card while you can).

1. From Control Panel, double-click on the DirectX applet to find out what version you have installed (if there's no applet in Control Panel, find and run dxdiag.exe, probably located in the System32 subdirectory of your C:\Windows or C:\WINNT directory). If you don't have version 7 or higher of DirectX, download the latest version from Microsoft's web page.
2. Start GraphEdit. Under the Graph menu, select Insert Filters, then insert all of the following:

- Under WDM Streaming TV Tuner Devices, select the TVTuner filter (it will be specific to your TV capture card, for instance "ATI TVTuner"). You only need this filter if you need to tune to a specific channel. If you use RCA or S-Video cables to connect to the TV Capture card, don't add this filter.
- Under WDM Streaming Crossbar Devices, select any filters you find--there should be one or two. For the ATI-TV Wonder PCI, the two are "ATI Crossbar" and "ATIBt829 Crossbar" ("Bt829" refers to the Brooktree 829 chip).
- Under WDM Streaming Capture Devices, select the filter specific to your TV capture card. The filter for the ATI-TV Wonder PCI is "AtiBt829 Capture".
- Under WDM Streaming Tee/Splitter Devices, select the "Tee/Sink-to-Sink Converter".
- Under DirectShow Filters, select the "VBI Surface Allocator". For Windows XP, select the "Video Port Manager" filter instead.
- Under WDM Streaming VBI Codecs, select the "CC Decoder".
- Under DirectShow Filters, select the "Line 21 Decoder". If you're working in Windows XP, use the "Line 21 Decoder 2" instead.
- Under DirectShow Filters, select the "Dump" filter. This is the filter that will output the raw closed caption file, and when you select this filter, you will be prompted to provide a path and name of the file to create ("cc.bin" is a good generic name). Note: The File Writer filter, although it appears to do the exact same thing as the Dump filter, cannot be made to connect to the other filters. The Dump filter was added when you ran the batch file that came with Doom 9's version of Graph Edit. If you ran this file and still don't have the Dump filter, edit the batch file in Notepad, adding the line "`set path=%path%;.`" at the top, then run it again.
- Under DirectShow Filters, select the "Overlay Mixer" (do not add this filter for Windows XP).
- Under DirectShow Filters, select the "Video Mixing Renderer" for Windows XP or the "Video Renderer" for other operating systems. Then click the Close button to return to GraphEdit. Note: At least one Windows XP user has reported that the "Video Mixing Renderer" was mistakenly named "Video Renderer", sitting right next to the non-functional "Video Renderer" filter from pre-Windows XP.

3. To create an application, you will now connect the filters (the boxes in GraphEdit) to each other to pass data down the line. To connect two boxes, position the pointer in an output pin (one of the bumps on the right-hand side of a box) and drag to an input pin (a left-hand bump on another box). If the two filters cannot be connected, you will get a cryptic error message--try closing and re-opening GraphEditor and if this and a reboot doesn't work, then it's possible the card just doesn't want to do what you want. To configure a filter, right-click it and select "Filter Properties". Finally, to delete a filter, click on it to select it, then press the Delete key. Look here for an example of what this should look like when finished (using a ATI-TV Wonder PCI card in a Windows 98 system).

1. If you are using the tuner, connect the Analog Video output of the TVTuner filter to the Video Tuner In of the first crossbar filter (if you have only one crossbar filter, it's the first one; otherwise, the one that doesn't have a Video Decoder Out output is the first one). Configure the filter to select your broadcast standard (NTSC-M in North America) and the channel you wish to capture from.
2. If there are two crossbar filters, connect them based on how your video signal is going into the card: Video Tuner Out to Video Tuner In, Video SVideo Out to Video SVideo In, or Video Composite Out to Video Composite In. Configure both crossbar filters to select the video source.
3. Connect the Video Decoder Out of the second (or only) crossbar filter to the Analog Video In of the capture filter.
4. If the capture filter has a Preview output pin, connect it to Input0 of the Overlay Mixer (for non-Windows XP environments) or Input0 of the Video Mixing Renderer (for Windows XP). Otherwise, make the same connection with the Capture output pin of the capture filter.
5. If the capture filter has a VPVBI output pin, connect it to the VBI Notify input pin of the VBI Surface Allocator filter (for non-Windows XP systems) or the same pin on the Video Port Manager filter. If the capture filter does not have this pin, then this filter is not needed, and can be deleted. In case you are wondering, the purpose of this dead-end filter is to allocate memory on the video card to use the VBI output pin.
6. Connect the VBI output pin of the Capture filter to the Communication Transform input pin of the Tee/Sink-to-Sink Converter filter. If you don't have a VBI output pin, but do have a HWCC output pin, then you don't need the Tee/Sink-to-Sink Converter filter. If you don't have either of these pins, then the driver for your TV capture card does not support Closed Caption display or capture. Either find another driver (see here) or return the card and get a different one.
7. If you used the Tee/Sink-to-Sink Converter filter, connect its output pin to the VBI input pin of the CC Decoder filter. If you didn't use this filter and the capture filter has a HWCC output pin, connect this pin to the HWCC input pin of the CC Decoder filter.
8. Connect the CC output pin of the CC Decoder filter to the XForm In pin of either the Line 21 Decoder filter (for non-Windows XP) or the Line 21 Decoder 2 filter (for Windows XP). Note that a second CC output pin will appear on the CC Decoder filter when you do this.
9. Connect this second CC output pin to the input pin of the Dump filter (the name of this filter will be "cc.bin" or whatever else you called your capture file). By default, this will save Line 21 Field 1 data, which includes channels CC1 and CC2 (primary and secondary closed captions), T1 (text) and T2 (ITV). By right-clicking on the CC output pin, you can change the data source to be Line 21 Field 2 (also known as Line 284)--this will change the output to only contain CC3 (XDS).
10. For non-Windows XP systems, connect the XForm Out pin of the Line 21 Decoder filter to the Input2 pin of the Overlay Mixer filter (which you used back in step d). For Windows XP, connect the XForm Out pin of the Line 21 Decoder 2 filter to the Input2 pin of the Video Mixing Renderer filter.
11. For non-Windows XP systems, connect the XForm Out pin of the Overlay Mixer filter to the Input of the Video Renderer. Windows XP users don't need to do anything for this step.

4. Save the resulting graph.
5. To capture closed captions, set up your video source, then click on the play button in the toolbar of GraphEdit. A small preview window should open showing the video with closed captions overlayed. There will be no sound and the video may be in black and white, but as long as closed captions are being displayed, they will also be captured. The filter graph will only display channel CC1 (for Field 1) or CC3 (for Field 2), but despite this you are actually capturing everything transmitted on whichever Line 21 field you selected to capture.
6. Monitor the preview window until all of the captions you are interested in have been displayed, then click the stop button in the toolbar of GraphEdit to stop recording. DO NOT close the preview window before stopping GraphEdit, as that will crash the computer (you should close the window once you have stopped GraphEdit, though).
7. Take a look at the file you have created, to make sure that it is not an empty file. The contents of the file are in binary, so they should look like gibberish, with a few letters here and there.
8. You can now proceed to convert this file to SCC format.

Getting Raw Closed Caption Data from a VCD

Closed Captions for VCDs are not completely documented anywhere on the Internet, largely because the format has been abandoned for commercial purposes in North America (I presume they are documented in the White Book specifications, but not only is this $200, but any potential buyers are required to sign a non-disclosure agreement that would defeat the purpose of buying them in the first place). The only VCDs that are being made today lack closed captions.

The vast majority of the often poorly-formatted specifications for VCDs and SVCDs found on the 'net derive from the Philips PDF Super Video Compact Disc, a Technical Explanation. This document states two ways that closed captions are stored on a VCD: as the file EXT\CAPTnn.DAT, and in the form of user data embedded in the MPEG file.

There should be one CAPTnn.DAT file for each track of the VCD (so the closed captions for the AVSEQ02.DAT file are stored in CAPT02.DAT). The format of this file is spelled out in a document on the CD-I website. This page reveals that CAPTnn.DAT format is not the same as the EIA-608 format used for broadcast, videotapes and DVDs. It also shows that the file is specifically designed for CD-I players, and therefore will not be used by VCD or DVD players.

I know much less about the user data method. Looking at the source code for the VCDImager tool (starting with version 0.7.4), I can see that the user data header (0x000001b2) is followed by 0x11, but no details are given of the further structure. This rules out the DVD closed caption structure, which uses 0x43, and also the SCTE 20 2001 structure (0x03).

I have been looking for old commercial VCDs on e-bay, in order to reverse-engineer the format. So far I have a Swedish version of Ghost that verifies the CAPTnn.DAT format but lacks user data captions. If anyone can help me in this area, I'd really appreciate it (go to the bottom of this document to get my e-mail address). On the other hand, it's a good bet that no DVD player in existence (either software or hardware) would be capable of playing VCD user data closed captions, as it is likely their developers had the same incomplete documentation as I do.

Converting Raw Closed Caption Data to SCC Format: RAW2SCC

Once you have captured raw closed caption data, you can either convert it to subtitles (using the CCParser program available at Doom9), or you can use the RAW2SCC tool to convert it into the SCC format used by many high-end DVD authoring programs to store closed captions. (CCParser by the way requires the raw captions to be in DVD-format, so you will have to use RAW2SCC followed by SCC2RAW `-d` to convert broadcast-format into DVD-format.) To use RAW2SCC, run it from the command prompt with the name of the raw file to convert. Optionally, add a second argument with the name of the SCC file to create if you don't want it to be the name of the input file with the extension changed to .scc.

Here is a sample SCC file to show how the format works:

    Scenarist_SCC V1.0

    01:02:53:14	94ae 94ae 9420 9420 947a 947a 97a2 97a2 a820 68ef f26e 2068 ef6e 6be9 6e67 2029 942c 942c 942f 942f

    01:02:55:14	942c 942c

    01:03:27:29	94ae 94ae 9420 9420 94f2 94f2 c845 d92c 2054 c845 5245 ae80 942c 942c 8080 8080 942f 942f

A file represents the data in either Field 1 or Field 2 of Line 21, but not both (the Field 1 file always has an extension of `.SCC`; the Field 2 file is supposed to have the extension `.SC2`, but it is usually `.SCC` as well). It is possible to determine the field by examining the contents (for example, if you see `94ae` or `1cae`, then it's a Field 1 file, but if you see `15ae`, `9dae` or anything starting with `01`, then it's a Field 2 file), but as the example shows, it isn't easy.

The file is double-spaced, with blank lines between each line of data. The first line consists of the header "Scenarist_SCC V1.0" (version 1.0 is as high as this format ever got).

The third and following alternate lines consist of a timecode (which can use either the non-dropframe or dropframe formats, see below), followed by a tab, followed by space-delimited data. Usually, each line is a separate caption.

The timecode is in SMPTE format, or hours:minutes:seconds:frames. Since Line 21 Closed Captions is an NTSC format, there are 29.97 frames per second. NTSC timecodes can be displayed in one of two slightly-different formats. In non-dropframe time base, frame counts are translated straight into SMPTE. This is the usual format for NTSC content that has no contact with a broadcast environment. For a broadcast setting, timecodes are easier to work with if you start with 30 frames per second and then subtract 3 % to get 29.97. This is called dropframe time base, and is accomplished by skipping the first two frames at the beginning of every minute for nine out of every ten minutes. Dropframe timecodes are distinguished from non-dropframe timecodes by changing the last colon into a semicolon (`00:01:00;04` instead of `00:01:00:04`). Note that the difference between non-dropframe and dropframe is purely in how timecodes are displayed; underneath, 29.97 frames are still passing every second. RAW2SCC uses non-dropframe time base by default. [Thanks to Dan Wilson for making this all clear to me.]

The data is made up of pairs of hexadecimal numbers. Each pair can either represent a command (for positioning and other special effects), or a pair of characters. One pair is transmitted with each frame of video.

Getting back to the RAW2SCC tool, you can use any of the following optional arguments with it (place them between the command and the name of the input file):

`-1`, `-2`, or `-12`
  Selects which field to extract from the input file (`-12` means to extract both of them and output to two SCC files, with "_1" added to the name of the Field 1 file and "_2" added to the name of the Field 2 file). `-1` is the default. Note that none of these options apply if the input file is in broadcast format, as that format only supports a single field's data.
`-oHH:MM:SS:FF`
  Adds offset to all timecodes. HH:MM:SS:FF is the timecode to offset by, in SMPTE format. If you're setting the timebase to dropframe, you should use dropframe timecode format (`HH:MM:SS;FF`).
`-fNFPS`
  Changes the number of frames per second (NFPS). The program allows a range of 12 to 60 (use 25 for PAL video). Be sure to use the same framerate and timebase (see the next argument) for the video and the accompanying captions. The default value is 29.97, which represents non-dropframe NTSC video.
`-td`
  Sets the NTSC timebase. Possible values are `n` for non-dropframe or `d` for dropframe. The default is `n`. This flag will automatically set NFPS to 29.97, so don't mix the `-f` and `-t` arguments in the same command line.
`-lN`
  Sets the mid-line null count limit. Closed captions as they are usually broadcast often have null codes (`8080`) transmitted sporadically in order to get the timing right. RAW2SCC will split a line if it detects 2 or more null codes in a row. If you're trying to get your SCC files to have one entire caption per line, use `-l` to increase the number of null codes allowed in the middle of a line before the line is split, for example `-l8` to increase the limit to 8.

Ripping SCC Captions from a DVD: VobSub and VOBSUB2SCC

Until recently, the only way you could get closed caption data out of a DVD was to build a filter graph similar to the one described for analog capture, and then play the whole DVD out in real time. For these DVD's where the new procedure doesn't work, you can try the old method by following the instructions here. With the tool CCExtract, you can extract the captions from the ripped MPEG-2 files (you can also choose which field to extract, unlike VobSub, which only extracts Field 1). The following process is an alternative to try in case that doesn't work.

Starting with version 2.19, Gabest's VobSub tool (which is designed for the two purposes of burning subtitles into video files or displaying them on top of video by use of an included filter) is capable of ripping Closed Captions from a DVD and converting them to the popular Subrip subtitle format. As a byproduct of this process, a temporary file is created that can be converted straight to an SCC file by using the tool VOBSUB2SCC. Gabest has recently developed a VobSub Ripper Wizard tool that makes this process even easier:

1. Rip the necessary files from the DVD to the hard drive (there are numerous tools and guides for doing this available at Doom9). All you need are VOB and IFO files for the VTS with the most files (usually VTS_01_?.VOB and VTS_01_0.IFO), plus VIDEO_TS.IFO and VIDEO_TS.VOB.
2. Launch the VobSub Ripper Wizard. Click the Load IFO button and browse to the IFO file you copied. Then click the Save To button and select the directory to store the captions in, then click Next.
3. You will now see a dialog screen to select which streams you wish to process. By default, everything will be selected. If you don't want the DVD's subtitles, unselect everything. A checkbox controls whether the closed captions will be extracted. If it is unchecked when the dialog first appears, this probably means that the tool cannot find any captions. I have a DVD (Warner Brothers Superman: The Movie) that suffers from this problem (despite definitely having closed captions), and I find that the GraphEdit method doesn't work on it, either. Perhaps some DVDs store their closed captions in a different way than most.
4. Click on the Next button to start the extract process. The speed of this depends on the speed of your DVD drive: I was able to get a 90 minute movie on my Pioneer DVR-103 in about 20 minutes. If you include any subtitle streams in the processing list, the extract will take longer, but you will be able to extract those subtitles using the SubResync tool included in the VobSub downloads linked above. If you want the SubResync OCR process to be automated, download this, install it, copy the files dlltwain.dll, english.wdc and ocrdll.dll into VobSub's directory, re-launch SubResync, click Open, browse for the .idx file created in Step 3, click Save As, select the format you want, check the "Use ocrdll.dll checkbox", enter your filename, and click Save to start the process.
5. If you go to the directory you selected in Step 3, you will see the following files (assuming that you ripped VTS_01):

`VTS_01_0.idx` | Not needed (used by VobSub).
`VTS_01_0.sub` | Not needed (used by VobSub).
`VTS_01_0.cc.raw` | This is the file that we will convert to into SCC format.
`VTS_01_0.cc.srt` | This is the Subrip file created from the captions. If you were after subtitles and had no interest in SCC files, you'd stop here.
`VTS_01_0.cc.unicode.srt` | The Unicode-encoded version of `VTS_01_0.cc.srt`. The Closed Caption character set contains several unusual characters not usually encountered in subtitles, with the musical note character the most popular. These special characters cannot be stored in an ordinary ANSI text file and must use Unicode formatting. Unfortunately, the Subrip program and virtually every other program that uses subtitles can't open Unicode-formatted files. Therefore this file, while much more accurate than `VTS_01_0.cc.srt`, is virtually useless.

6. Bring up a command prompt, navigate to the directory with the .cc.raw suffix, and run VOBSUB2SCC.EXE with the .cc.raw file's name as the only argument. The tool will create two files: one with a .bin extension for the raw Line 21 Closed Caption data, and another with an .scc extension for the SCC-formatted data.

Since VOBSUB2SCC is creating two files, it does not accept output file names as parameters. This means that the name of the file to be converted must end with ".cc.raw" (or ".sub.cc.raw", the output of the previous VobSub program). The following optional arguments can also be used with VOBSUB2SCC:

`-oHH:MM:SS:FF`
  Adds offset to all timecodes. HH:MM:SS:FF is the timecode to offset by, in SMPTE format. If you're setting the timebase to dropframe, you should use dropframe timecode format (`HH:MM:SS;FF`).
`-fNFPS`
  Changes the number of frames per second (NFPS). The program allows a range of 12 to 60 (use 25 for PAL video). Be sure to use the same framerate and timebase (see the next argument) for the video and the accompanying captions.
`-td`
  Sets the NTSC timebase. Possible values are `n` for non-dropframe or `d` for dropframe. The default is `n`. This flag will automatically set NFPS to 29.97, so don't mix the `-f` and `-t` arguments in the same command line.
`-lN`
  Sets the mid-line null count limit for parsing the SCC file. See RAW2SCC for an explanation.

For details of the formatting of the SCC file created by this process, see the RAW2SCC section above.

Extracting Closed Captions from MPEG Files: General Parser and ccExtract

Captions are stored within MPEG-2 video and system files. The specific manner they are stored in varies based on the source of the file. MPEG-2 files ripped from DVDs use one format, and each of the different manufacturers of DVB (Digital Video Broadcast) recorders use a different format.

The General Parser tool (written by Takaaki Oka) is designed to quickly search through an MPEG file to output any customized data you might be interested in. The download for SCC_TOOLS includes two files to add to General Parser to allow it to extract closed captions in the raw format from MPEG files with a variety of different sources. So far, here is the list of sources supported:

1. DVD
2. "DVD": Hauppage WinTV PVR-250 and other MPEG-2 recording cards (note first that this card uses a defective version of the true DVD format and, second, that the card does not add captions to the files it captures by default--see here for how to turn this feature on)
3. "DVD": Panasonic DVR-E50H and other standalone DVD recorders that use the DVD-VR format. A number of DVD recorders offer the use of DVD-VR as an editable alternative to the DVD-Video format used by commercial DVDs (DVD-VR uses a DVD_RTAV folder instead of VIDEO_TS, and .VRO files instead of .VOB files). These machines record DVD-Video closed captions in DVD format, and DVD-VR captions in the same DVD format variant used by the PVR-250. Authoring tools such as TMPGEnc DVD Author can convert DVD-VR format, but lose the captions.
4. DVB: Dish Network
5. DVB: ReplayTV 4000 series
6. DVB: ReplayTV 5000 series
7. ATSC: Pinnacle MediaCenter (and hopefully ATSC-format files generated by any other means)
8. DSS-SD

To install General Parser, download it from here and unzip to a directory (such as C:\Program Files), then create a shortcut to General Parser\bin\gp.exe. Open SCC_TOOLS.ZIP, put CCExtract.gp and CCExtract_VES.gp in General Parser\projects\MPEG\video, and put CCExtract.bdl in General Parser\source\MPEG.

Here is the procedure to extract closed captions from an MPEG (or .VRO) file:

1. Launch General Parser.
2. From the File menu, Open Project and select General Parser\projects\MPEG\video\CCExtract.gp.
3. After the project compiles, select Open Bitstream from the File menu and select the MPEG file you wish to work with. The program will probably work with both system and elementary video files, but if you are having problems with a system file, try demuxing it and using CCExtract_VES.gp for the project file instead of CCExtract.gp (for elementary files and .VRO files, change "Files of type" to all files in order to see them).
4. At the bottom of the screen you will see a box with the number 10000000, which is the number of bytes in the MPEG file to process. Unless you only want the beginning of the file to be processed, insert three 0's in there (bringing it up to about 10 GB). You can permanently set this scope size in the Options dialog (located under the Tools menu).
5. From the File menu, select Restart and Save Output As. This will prompt you for the name of the raw caption file to create (something like "caption.bin" is good).
6. After a warning screen, you will see a dialog box asking which Field you wish to extract. If it's incorrect, double-click on the line and change the number (1 for captions, 2 for XDS).
7. CCExtract.gp will have another dialog box at this point. Accept the default values by clicking OK.
8. Click Accept to extract the captions. The progress will be shown by a bar at the bottom of the screen.
9. At this point you can extract the other field (Step 5) or load another MPEG to work with (Step 3).
10. Use RAW2SCC to convert the raw caption file into SCC format.

If you are having problems trying to process large files, try increasing the numbers in the Pipeline and Virtual Machine tabs of the Options Dialog.

If you have a file from a source other than those listed at the top of this section, try to use CCExtract on it. If it works, let me know which source it was so I can add it to the list. If it doesn't work, you can help me to add the new source to this tool by the following:

1. Download the diagnostic tool DVBDUMP.
2. Run the file with the name of your file as the argument. The program will produce a `.txt` file.
3. E-mail the `.txt` file to me with an explanation of the source you are using (see the bottom of this page for the address).
4. The tool is designed to only process 100 rows of output, so the file produced will not be too big. If it produces an overly-small file, try using the argument `-d1000` between `dvbdump` and the input file name to produce a 1000-row output.

Before Jeff Davies alerted me to the existence of General Parser, I had my own tool, SCC_RIP, which had to be one of the slowest programs on the planet. However, I imagine the day might come where nothing else works, so here's how to use this tool:

Run SCC_RIP it with the name of the MPEG-2 file as the argument. The program will (eventually) output two files with the same base name as the MPEG-2 file: a raw file (extension `.bin`) and an `.scc` file. The following optional arguments can also be used with SCC_RIP:

`-d`
  Outputs the raw file in DVD format instead of broadcast format. Use this option if you want to use the CCParser program to convert the captions to SubRip subtitles (download CCParser from Doom9).
`-1`, `-2`, or `-12`
  Selects which field to extract from the input file--`-1` is the default. Option `-12` will extract both fields; how many output files this produces depends on the raw format: broadcast format can only hold one field, so there will be four output files (input_1.bin, input_2.bin, input_1.scc and input_2.scc), while DVD format can hold both fields, so there will only be three output files (input.bin, input_1.scc and input_2.scc).
`-oHH:MM:SS:FF`
  Adds offset to all timecodes. HH:MM:SS:FF is the timecode to offset by, in SMPTE format. If you're setting the timebase to dropframe, you should use dropframe timecode format (`HH:MM:SS;FF`).
`-fNFPS`
  Changes the number of frames per second (NFPS). The program allows a range of 12 to 60 (use 25 for PAL video). Be sure to use the same framerate and timebase (see the next argument) for the video and the accompanying captions.
`-td`
  Sets the NTSC timebase. Possible values are `n` for non-dropframe or `d` for dropframe. The default is `n`. This flag will automatically set NFPS to 29.97, so don't mix the `-f` and `-t` arguments in the same command line.

Extracting Closed Captions from DVR-MS Files: DVR2SCC

Windows XP Media Center PCs record video in a proprietory format with the extension .dvr-ms. Tools have been developed to convert this format into MPEG, but in the process the closed captions which are included in the format are lost. The DVR2SCC tool will extract the captions from a Media Center file, both in raw format (.bin extension) and in SCC format. To use the tool, run it from a command prompt with the .dvr-ms file as the argument. Since there are two output files, DVR2SCC will not accept output filenames as parameters. The following optional arguments can also be used:

`-d`
  Outputs the raw file in DVD format instead of broadcast format. Use this option if you want to use the CCParser program to convert the captions to SubRip subtitles (download CCParser from Doom9).
`-oHH:MM:SS:FF`
  Adds offset to all timecodes. HH:MM:SS:FF is the timecode to offset by, in SMPTE format. If you're setting the timebase to dropframe, you should use dropframe timecode format (`HH:MM:SS;FF`).
`-fNFPS`
  Changes the number of frames per second (NFPS). The program allows a range of 12 to 60 (use 25 for PAL video). Be sure to use the same framerate and timebase (see the next argument) for the video and the accompanying captions.
`-td`
  Sets the NTSC timebase. Possible values are `n` for non-dropframe or `d` for dropframe. The default is `n`. This flag will automatically set NFPS to 29.97, so don't mix the `-f` and `-t` arguments in the same command line.

For details of the formatting of the SCC file created by this process, see the RAW2SCC section above.

Converting Subtitles into Closed Captions: SUBRIP2SCC

Occationally it happens that you have your hands on a set of subtitles but no closed captions. If you still wish to use captions, you can use the SUBRIP2SCC tool to convert subtitles in Subrip format to SCC format (Subrip format is the native subtitle format produced by Zuggy and Brain's SubRip DVD subtitle ripper). Realize that the output from SUBRIP2SCC still needs to be massaged before it can be used (by using CCASDI to convert to CCD format and then editing). In particular:

- Subtitles (particularly fansubs) tend to have very-long lines, while captions are limited to four lines of up to 32 characters each. SUBRIP2SCC will re-format lines to not go over these limits and will tell you which subtitles were so long they had to be truncated to fit. So expect the line breaks to be in the worst possible places.
- Closed Captions are potentially displayed much more slowly than subtitles. Closed Captions have to be built up in a buffer before they can be displayed, and this process takes time, around 10 characters per second. If a subtitle is timed to appear too soon after a previous one, there will be trouble converting the times over to the captions. SUBRIP2SCC's response to this problem is to move the start time forward as necessary to prevent overlap between captions. As a result, these captions will appear late and may be replaced by the next (on-time) caption before the viewer has had a chance to read it. SUBRIP2SCC will tell you which Subrip lines it had to modify. If you want to see how much the times were changed, run CCASDI on the SCC file with the `-a` argument to adjust the CCD times to match the Subrip times. The only rows that should be off by more than half a second will be the ones SUBRIP2SCC told you it had to adjust.
- Subtitles can include images, while closed captions can include some odd characters like the Eighth Note and the Service Mark. At least for the moment, SUBRIP2SCC is not capable of processing Unicode-formatted files, which would be able to support the odd characters if they happened to be found in Subrip files. On the other hand, Subrip subtitles tend to use the "`*`" character to represent the Eighth Note, and SUBRIP2SCC will automatically convert all asterisks to musical notes (as the asterisk is a mostly-unsupported character for captions).
- Bold formatting (indicated in SubRip by surrounding the line with `<b>` and `</b>` tags) will be dropped, because closed captions are only in bold text. However, italics (`<i></i>`) and underline (`<u></u>`) are converted correctly.
- As of version 1.15 of SubRip, the subrip format can now encode character colors in HTML color format (`<font color="#rrggbb"></font>`), with over sixteen million different colors possible. Closed Captions only support eight different colors (white, black, red, green, blue, cyan, magenta and yellow), so SubRip colors are converted to the nearest Closed Caption match.
- Subtitles typically don't include stage directions like sounds, which captions do.
- Subrip subtitles almost never include positioning information, so SUBRIP2SCC simply centers every line, putting "dialog" at the bottom of the screen and "stage directions" at the top (as far as SUBRIP2SCC is concerned, if a line begins with "[" or "(", it's a stage direction; if not, it's dialog).
- Subtitles look like subtitles, not closed captions. If you want your converted captions to look like broadcast-style captions, refer to the Closed Caption Style Guide.

SUBRIP2SCC accepts the name of a Subrip file (suffix .srt) as its required argument and optionally accepts another argument of the output file (assumed to be the input file with an .scc suffix if left out). The input file must end with a blank line, or SUBRIP2SCC will drop the last subtitle. The following additional arguments (placed between "SUBRIP2SCC" and the input file name) are all optional:

`-2`
  Outputs the captions for channel CC2 instead of the default CC1. Useful only if you wanted to build an SCC file with two different closed caption streams.
`-u`
  Follows the Closed Caption style guide by converting all dialog to uppercase.
`-k`
  Turns off the default conversion of "`*`" characters to eighth note characters. Since the asterisk is an extended character in closed closed captions (and therefore unreliably supported by software DVD players and other display devices), and because Subrip files cannot include Unicode characters like the eighth note, I'd recommend using asterisks only to represent musical notes.
`-oHH:MM:SS,MIL`
  Applies an offset to every timecode. HH:MM:SS,MIL is the amount of the offset in Subrip's format of hours, minutes, seconds, and milliseconds. A negative value like `-o-00:01:00,000` is allowed.
`-fNFPS`
  Changes the number of frames per second (NFPS), used when converting SubRip timecodes to the SMPTE timecodes used by SCC. The program allows a range of 12 to 60 (use 25 for PAL video). Be sure to use the same framerate and timebase (see the next argument) for the video and the accompanying captions.
`-td`
  Sets the NTSC timebase for timecode conversion. Possible values are `n` for non-dropframe or `d` for dropframe. The default is `n`. This flag will automatically set NFPS to 29.97, so don't mix the `-f` and `-t` arguments in the same command line.

NOTE: There are dozens of subtitle formats out there that can be converted to Subrip format for use with this tool. If you are looking for a good converter for the common Sub-Station Alpha (SSA) format, I'd recommend Radek Strugalski's SubCreator. This is also a fine free tool for creating subtitles from scratch and timing against a video file.

Converting Between Closed Caption Formats: PAS2SCC

Although SCC is the accepted standard for storing closed captions, it is not the only such format in existence--every commercial captioning product out there uses their own format, although most of these tools will include the ability to export to SCC format. As I am presented with examples of these formats, I will develop tools to perform these conversions, for the use of those with odd-format captions but lacking the tools that created them.

The first such format I have received was created by the DOS version of CCWriter, with the extension `.pas`. The corresponding conversion tool is PAS2SCC. To use it, run from the command line with the name of the .pas file as the argument. The output will be in .scc format.

Here is an example of what CCWriter (DOS) format looks like:

    ;THE SINGING RIVER: RHYTHMS OF NATURE
    ;File:    PART1.PAS
    ;created: 10/31/03
    ;transc. by: EVC
    ;captioned by: SRC
    ;air date: 11/13/03
    ;length: 58:55

    ,mbc
    \THE SINGING RIVER\
    CLOSED CAPTIONED
    + 00:01:15F00   00:01:23F08

    (\soft music and
    \birds singing\)
    + 00:01:40F18   00:01:43F27

    ,mbc
    THE RIVER IS LIKE
    AN ARTERY OF LIFE
    + 00:01:44F27   00:01:50F29

PAS2SCC will also accept the following optional arguments:

`-2`
  Output the captions in Channel 2 instead of Channel 1.
`-ohh:mm:ssFff`
  Applies an offset to every timecode. hh:mm:ssFff is the amount of the offset in CCWriter's format of hours, minutes, seconds, and frames (with `F` separating seconds and frames). A negative value like `-o-00:01:00F00` is allowed.
`-fNFPS`
  Changes the number of frames per second (NFPS). The program allows a range of 12 to 60 (use 25 for PAL video). Be sure to use the same framerate and timebase (see the next argument) for the video and the accompanying captions.
`-td`
  Sets the NTSC timebase for timecode conversion. Possible values are `n` for non-dropframe or `d` for dropframe. The default is `n`. This flag will automatically set NFPS to 29.97, so don't mix the `-f` and `-t` arguments in the same command line.

Converting SCC to a Readable Format: CCASDI

Closed captions are frequently different from the actual dialog spoken. Part of this is due to the relatively low bandwidth (less than ten words per second, closer to ten characters per second when you consider all of the commands that are sent before and after each caption), but in addition, a number of typographical errors tend to sneak in. There are a number of tools for editing closed captions and outputting SCC files, but none of these are free (the least expensive is Jorge Morones' Stream SubText). What is needed is a free alternative, a way to turn SCC files into a human-readable format and back, so SCC files can be created and edited. The tool for this job is CCASDI, the Closed Caption ASsembler and DIsassembler), and the human-readable format it uses is CCD, for Closed Caption Disassembly (this format is described in the next section). To use CCASDI, run it from the command prompt with the name of the file to convert (and optionally, the name of the file to create). The program will automatically detect the type of the file (SCC or CCD) and will output a file of the opposite type.

The following optional arguments can be used with CCASDI:

`-a`
  This argument will cause the timecodes to be automatically adjusted: SCC files will have timecodes for the start of the caption, while CCD files will have timecodes for the moment the caption is to be displayed or removed. Use this option just so the timecodes are easier to understand, as it is easy to mess up the timecodes by using this option and then not remembering to use it again to undo the effect.
`-s`
  This argument only works when the input is an SCC file. It acts to convert the file into a subtitle format, adjusting timecodes as it goes (see `-a` argument above). Note that if the captions are in the roll-up format (i.e. if they came from a news broadcast or any other live source), then each SCC line must have an entire caption, so you may need to adjust the `-l` parameter of RAW2SCC to get this conversion to work. The default output if you don't provide the output file argument is SubRip format, changing the input file extension of .scc to .srt. Underline, italics, and color formatting are converted, but not flash (which no subtitle format supports). Note that all captions should be in boldface, but I figured that most users would not want `<b></b>` tags around every single subtitle. By providing an output file argument with one of the following extensions, you can change the format of the subtitles created:
  - `.srt`: SubRip format (see above)
  - `.sub`: MicroDVD format (does not support colors)
  - `.smi`: SAMI format (supports all SubRip formatting)
  - `.psb`: PowerDivX format (does not support any formatting)
  - `.ssa`: Sub-Station Alpha format (supports all SubRip formatting)
  - `.ass`: Advanced Sub-Station format (supports all SubRip formatting)
  - `.txt`: Adobe Encore format (does not support any formatting)
  I can implement other conversions upon request.
`-cCC1`
  Specifies which data stream to convert to subtitles (i.e. it only works with the `-s` option). The default is `CC1`, the first closed caption stream, which is the one used for DVD's, videotapes and almost all broadcast captions. Other choices are `CC2`, `CC3`, `CC4`, `T1`, `T2`, `T3` and `T4` ("`T`" refers to Text streams, which are very rarely used nowadays).
`-oHH:MM:SS:FF`
  During the conversion, applies an offset to every timecode. HH:MM:SS:FF is amount of the offset as a timecode, in SMPTE format. For the FF frames value, the non-dropframe time base will be used, unless the `-td` argument is used (in which case the timecode should be in `HH:MM:SS;FF` format).
`-fNFPS`
  Changes the Number of Frames Per Second. This argument only makes sense if it accompanies the `-o` argument. NFPS can be between 15 and 60.
`-td`
  Sets the NTSC timebase to either non-dropframe (`n`) or dropframe (`d`). The default is `n`. Using this argument automatically sets Frames Per Second to 29.97.

The Closed Caption Disassembly Format

Here is the CCD (Closed Caption Disassembly) version of the sample SCC file given in the RAW2SCC section above:

    SCC_disassembly V1.2
    CHANNEL 1

    01:02:53:14	{ENM}{ENM}{RCL}{RCL}{1520}{1520}{TO2}{TO2}( horn honking ){EDM}{EDM}{EOC}{EOC}
    01:02:55:14	{EDM}{EDM}
    01:03:27:29	{ENM}{ENM}{RCL}{RCL}{1504}{1504}HEY, THERE_{EDM}{EDM}{}{}{EOC}{EOC}

The first line consists of the header "SCC_disassembly V1.2". Versions 1.0 and 1.1 were produced by earlier versions of CCASDI (1.0 and 2.0), and there is a limited degree of backward-compatibility if you have an earlier-version CCD file to convert to SCC (CCD is an editing format, though, so you should use SCC as the more-stable storage format).

The second line gives the channel to display the captions in. Line 21 Closed Captions support Channels 1, 2, 3 and 4, allowing two data streams to be transmitted from each of two fields of Line 21 of the television signal (with a maximum bitrate of 60 characters per second allocated to each field). Nobody ever uses Channels 2 - 4 for DVD, and most PC DVD players are incapable of displaying captions from these channels, but in the broadcast world, Channel 2 is occasionally used to give the same captions in another language (Channels 3 and 4 are rarely used for alternate captions). Note that for backward-compatibility reasons, `FIELD` is also accepted as a synonym of `CHANNEL`.

The third line is blank.

The fourth and subsequent lines consist of a timecode, in SMPTE format (non-dropframe [`HH:MM:SS:FF`] or dropframe [`HH:MM:SS;FF`] format), followed a tab, followed by the data. Each line usually consists of a single caption.

The data consists of codes (in curly braces) and characters. One code or two characters can be transmitted each frame. Codes are always transmitted in pairs, to handle problems with bad TV transmissions. Even for DVD, the codes are usually doubled. Closed caption decoders are designed to ignore the second code in an identical pair.

Line 21 Closed Captions can include screens of Text, eXtended Data Service codes, Interactive TeleVision links, or Closed Captions. Closed Captions in turn can be displayed on four different channels and in one of three different formats. Luckily, only one specific combination is ever used in DVD's, videotapes and most programs broadcast on TV: Channel 1 Closed Captions in the Pop-On format. Pop-On Captions have the following format:

`{ENM}{ENM}`
  The Erase Nondisplayed Memory code clears the buffer that will be used to compose the caption. This code may be optional if the {EDM} code preceeds the {EOC} code (see below).
`{RCL}{RCL}`
  The Resume Caption Loading code defines the next caption to be of the pop-on type. All codes and characters that follow are written to the off-screen buffer until the {EOC} code is received.
`{####}{####}`
  The PAC (Preamble Address Code) positions the cursor on the off-screen buffer. The first two digits are the row, from 01 to 15, and the last two digits are the column, from 00 to 28. You can select any row, but the column must be evenly-divisible by 4 (00, 04, 08, 12, etc.). The actual display grid is 16 by 32 characters, as shown in this illustration. Optionally, column 00 can be replaced by any of the following:
  - `Wh`: This is the same as 00 (white text, no extra formatting).
  - `WhU`: White underlined text.
  - `WhI`: White italicized text.
  - `WhIU`: White italicized underlined text.
  - `Gr`: Green text.
  - `GrU`: Green underlined text.
  - `Bl`: Blue text.
  - `BlU`: Blue underlined text.
  - `Cy`: Cyan text.
  - `CyU`: Cyan underlined text.
  - `R`: Red text.
  - `RU`: Red underlined text.
  - `Y`: Yellow text.
  - `YU`: Yellow underlined text.
  - `Ma`: Magenta text.
  - `MaU`: Magenta underlined text.
  A caption can have multiple different PAC's (each followed by text), to create the effect of multiple people speaking at once.
`{TO#}{TO#}`
  The optional Tab Over code moves the cursor over an additional 1, 2, or 3 positions to the right of the PAC, without overwriting any characters that may lie between the PAC and the Tab Over position.
`ABCDEFG`
  The characters that make up the text of the caption appear at this point. Here is an illustration of the closed caption character set. Since characters are broadcast in pairs, the special non-displaying blank code "_" can be used at the end of a character sequence.
`{MRC}{MRC}`
  Interspersed with the characters can be one or more Mid-Row Codes:
  - `{Wh}`: Change to white text with no extra formatting.
  - `{WhU}`: Change to white underlined text.
  - `{Gr}`: Change to green text with no extra formatting.
  - `{GrU}`: Change to green underlined text.
  - `{Bl}`: Change to blue text with no extra formatting.
  - `{BlU}`: Change to blue underlined text.
  - `{Cy}`: Change to cyan text with no extra formatting.
  - `{CyU}`: Change to cyan underlined text.
  - `{R}`: Change to red text with no extra formatting.
  - `{RU}`: Change to red underlined text.
  - `{Y}`: Change to yellow text with no extra formatting.
  - `{YU}`: Change to yellow underlined text.
  - `{Ma}`: Change to magenta text with no extra formatting.
  - `{MaU}`: Change to magenta underlined text.
  - `{Bk}`: Change to black text with no extra formatting.
  - `{BkU}`: Change to black underlined text.
  - `{I}`: Change font style to italics (removing underline and flash).
  - `{IU}`: Change font style to italicized underline (removing flash).
  - `{FON}`: Change font style to flashing (without affecting italics or underline, if applied).
  Note that each pair of Mid-Row Codes moves the cursor over one space.
`{}{}`
  This is the null code. Its only purpose is to use up frames until the moment the caption is supposed to be displayed. It can appear anywhere in the caption, even between characters. All of the frames between the end of one caption and the beginning of the next (not displayed in SCC and CCD files) are made up of null code pairs.
`{EDM}{EDM}`
  The Erase Displayed Memory code clears the screen of captions. This code is often used on a line by itself to provide a spacer between captions (as shown in the next-to-last line of the sample).
`{EOC}{EOC}`
  The End Of Caption code swaps the screen and the buffer, displaying the caption you just created. Note that the `{EDM}{EOC}` combination automatically clears the buffer.

Here is a page describing characters in CCD files in detail, and here is a page describing CCD codes in detail (documenting the text mode and the three different closed caption formats for channels T1 - T4, CC1 - CC4).

For those interested in eXtended Data Service and Interactive TeleVision, you can find descriptions of how they are implemented in the CCD format here and here. Note that XDS was not correctly implemented when it was first added to CCD format version 1.2, and will only work with versions 1.3 (and above).

Adjusting Timecodes: CCADJ

There are a variety of reasons why you might want to adjust all of the timecodes in an SCC or CCD file by the same amount. One of the most common is the fact that the SCC files created by RAW2SCC arbitrarily assign a timecode of 00:00:00:00 to the frame when the raw capture started, and this is usually not the correct zero-point of the finished video. The tool for timecode adjustment is CCADJ.

To use CCADJ, run it from the command prompt with three arguments: "-o" followed by the timecode adjustment (i.e. -o01:00:00:00 to add an hour or -o-00:01:00:00 to subtract a minute), the name of the file to adjust, and the name of the adjusted file to create (this is the only tool where the output file name is not optional). If the files are not using the NTSC non-drop timebase and framerate, include either the `-f` or `-t` argument (`-f` followed by number of frames per second for different framerate, or `-td` to change the NTSC timebase from non-dropframe to dropframe). If you're using dropframe timecode, the timecode in the `-o` argument should be in the proper form (`HH:MM:SS;FF`).

You can also use CCADJ to speed up or slow down captions: use the `-m` argument with a factor to multiply against all timecodes. For example, if you timed your captions against a PAL version of the movie, use `-m1.199` to multiply all timecodes by 119.9%. If for some reason you wanted to perform the reverse of the procedure (say to convert NTSC into PAL subtitles using CCASDI `-s`), use `-m0.834` to multiply all timecodes by 83.4 %.

One possible use of CCADJ is to combine multiple closed caption files into a single file. Use CCADJ for each of the files after the first one to move the timecodes into the correct ranges, then cut and paste in a text editor to combine the contents of the resulting files.

Inserting Captions into MPEG Files: CC_MUX

Once you have extracted and manipulated your captions (or created them from scratch), you need some way to display them. If your target format is DVD and you own one of the three high-end DVD authoring tools (Sonic Scenarist, the discontinued Spruce DVDMaestro or Apple DVDStudioPro), you can supply the captions in SCC format and they will automatically be inserted in the final product. If you have some other DVD authoring tool, or if your target is a DVB machine, then you need to mux the captions into the MPEG file you're working with. The tool for this job is CC_MUX.

First, you need to have an MPEG file with any captions removed. The tool ReStream by shh (download from Doom 9) can show you if the MPEG file still has user data in it and can strip all user data from an MPEG file ("user data" is what closed captions are classified as). Chances are, if you did any re-encoding of the file (and that includes cutting on a non-GOP boundary), that the user data has already been stripped.

CC_MUX is the most complicated tool in the SCC_TOOLS package (and next to SCC_RIP, one of the slowest). Here are the arguments, which you can also see by running CC_MUX by itself in a command prompt:

`-cDVD`
  Format to put the captions in. Default is `DVD`, but `RTV4` and `RTV5` are also possible, for ReplayTV 4000 and 5000. Dish Network format is not yet supported because it is so complex (I can just figure out to read it, but it has odd counters and checksums in it that I do not know how to reproduce).
`-1caption.scc`
  Required argument for Field 1 closed caption input file. Format can be either SCC or raw caption (extension `.bin`)--if it's SCC, then temporary raw-format captions will be created ("temporary" in this case meaning that they will be left to clutter your hard drive).
`-2xds.scc`
  Optional argument for Field 2 XDS input file. See `-1` for more details on possible formats.
`-12dvd.bin`
  This option is provided on the off-chance you have a DVD raw format caption file with both fields in it.
`-oHH:MM:SS:FF`
  Offset to apply to the caption file(s) relative to the MPEG file. Format is the usual SMPTE (do I even need to explain SMPTE at this point?) and can be positive or negative. CC_MUX will attempt to read the start timecode for offset purposes from the MPEG input file, and will only assume it is 00:00:00:00 if such a timecode cannot be found. Assuming that both caption and MPEG files start from timecode 00:00:00:00, a positive offset would mean that the first closed caption packet in the output file would be moved forward from the beginning of the file, while a negative offset would mean that the captions would begin at the start of the output file, but would start somewhere after the start of the caption file(s).
`-fNFPS`
  Changes the Number of Frames Per Second (NFPS). If not provided, it will be taken from the MPEG file, and if not found there, it will default to 29.97. NFPS can be between 15 and 60.
`-td`
  Sets the NTSC timebase to either non-dropframe (`n`) or dropframe (`d`). If not provided, it will be taken from the MPEG file, and if not found there, it will default to `n`. Using this argument automatically sets Frames Per Second to 29.97.
`infile.m2v`
  Required name of MPEG file to insert captions into. This must be an elementary video file (default extension `.m2v`). Program files will probably not work as they depend on constant packet sizes, and adding captions will throw that off. Demux to elementary video and audio files, use CC_MUX on the video file, and re-mux the resulting video file together with the audio file to get a working program file.
`outfile.m2v`
  Optional name of the file to create (also an elementary video MPEG file). If not provided, CC_MUX will take the base name of the MPEG input file and add "_out" to it (i.e. "`infile.m2v`" will output "`infile_out.m2v`").

Turning back to DVD authoring with something other than a high-end tool, after you use CC_MUX to add the captions to the MPEG file, bring the output file into the authoring tool and then use the tool to create the DVD files, you need to manipulate the VTS_XX_0.IFO file to turn on a flag that tells the DVD player that captions are present. To do this in IfoEdit (a tool you can download from Doom 9), open the file, double-click the Video line in the VTS overview - Title Set (Movie) attributes and check one or both boxes under "CC for Line 21":

Converting SCC Format to Raw Format: SCC2RAW

The main purpose of this tool right now is to convert SCC files into the DVD raw format that CCParser requires. The tool will also convert SCC into broadcast raw format.

To use SCC2RAW, run it from the command prompt with the name of the SCC file to convert optionally followed by the name of the binary file to create (by default, the output file will have the same name as the SCC file with the suffix changed to .bin). To output in DVD format, include the additional argument of "`-d`". DVD format can include both fields, so you can include the argument "`-2`" to use Field 2 instead of the default Field 1, or "`-12`" to use both fields. If you want the output to start at some point other than 00:00:00:00 relative to the timestamps in the input files, include the argument "`-o`" followed by the offset (this can be negative)--this is one way to deal with the multi-part VCDs after the first part (assuming that raw closed caption format works with VCDs, which it apparently doesn't). If the files are not using the NTSC non-drop timebase and framerate, include either the `-f` or `-t` argument (`-f` followed by number of frames per second for different framerate, or `-td` to change the NTSC timebase from non-dropframe to dropframe).

McPoodle