TyDemux - README

TyDemux 0.5.0

TyDemux is a program to demux video and audio streams from a Tivo TyStream, and repair all dammage and mpeg errors therein.

Usage of TyDemux

tydemux -s [1/2] [options] -i tystream.ty -v output_video.mpg -a output_audio.ac3

Basic extraction

tydemux -s 2 -i tystream.ty -v output_video.mpg -a output_audio.ac3

In this mode, you will demux a Tivo version 2.x or higher tystream and get a nice progress meter and also some basic information about the TyStream. Only real errors will be reported.

-s 2 -s 1 no longer supported, use tydemux 0.4.2 if you want to demux Tivo version 1.3 streams.

Options

NOTE: I have temporarily disabled debug, will be back some time in the future.

-d 0 to 9 - sets the debug level, 1 is the default level.

0 == silent
1 == major errors and progress
2 == 1 + warnings
3 == 2 + parse, check, write info for each chunk
4 == 3 + record type of each record in the TyStream
5 == 4 + 16 bytes of record data of each record in the TyStream
6 == 5 + some more debugging info
7 == 6 + everything
8 == 7 + The whole record header printed in easy to read hex :)
Note: 3 and above is very verbose and is not recommended unless you have problems, and are sending bug reports.

Note: It can be nice to set the debug level to 2 since you will get information of skipped garbage chunks.

-c cutfile: a cut file created by TyEditor.
-h/-? Prints a usage message.

Return codes

Unix/Linux/MacOSX tydemux returns 0 if successful, 1 if you made a usage error and 2 upon error.

WINDOWS
tydemux returns the audio offset that has to be used when muxing the video and audio files up on success, tydemux returns -1000 on error and 1000 on usage error.

Changelog

0.1 Initial release.

0.2 Initial Windows release + bug fixes.
NOTE: Compile it with MS Visual Studio 6.x.

0.2.1 Bugfix - Seq header.
- Me my dumber, looked for the seq header but never used it, hence the extracted video ES stream didn't start with 00 00 01 b3 -> No muxing with e.g. mplex.

- Included sample program to extract samples of a TyStream (if I know get a really good FTP server - my pipe looks a bit bad and people are loosing connections)

0.3.0
Nearly total rewrite of the program.

- Totally new parsing and demuxing engine that will demux even the most difficult streams.
- Will demux TyStreams created with Tivo version 1.3 and up.
- Will demux TyStreams created both with Tivo Series 1 and 2.
- Will repair damaged TyStreams - TyStreams can have big holes and gaps, tydemux will detect those. Upon detection, it will align video and audio in such way that there is little to no loss in sync. Furthermore, tydemux will fix the start and end of the hole or gap in such way that the video and audio content doesn't deteriorate in quality.

0.3.1
- Fixed bug that can make tydemux core dump on truncated chunks at the end of the TyStream. I.E. if the last chunk in the TyStream is not properly extracted. - Fixed bug that can make tydemux core dump when it encounters invalid record types. Basically freed the chunk, then printed the data from the freed chunk. :( 0.4.0
Major update to tydemux.

New features are as follows:
- Large file support (files bigger than 2GB) on supported platforms.
- Check and fix of temporal reference.
- Correction of closed GOPs on Tivo Series 2 and 1.
- Frame correction if necessary (for under or overflow of frames).
- Check and correction of drift in A/V sync.

Fixes:
- Will detect Series 2 versus Tivo version 1.3 correctly.

0.4.1
New features are as follows:
- During the probe we will seek for the start of the chunk.
- Compensation for missing audio frames.
- Large file support under Windows.

Fixes:
- Fix of temporal reference check.
- Fix of temporal reference repair function.
- Fix of over flow repair.
- Fix of under flow repair.
- Fix of memory leak in get audio and video.
- Better detection of bad chunks.
- Fix of gap/repair indicator.

0.4.2
New features:
- Returns A/V sync offset under windows.
- Uses new -s switch for tivo version.
- BSD support - thanks, Kurt J. Lidl.

Fixes:
- Fix of close GOP when the SEQ is extremely short.
- Fixed a memory leak in read chunk during probe.
- Fixed the read chunk function - faulty detection of record type due to memory error.
- Fixed read chunk 0x000 is a valid record.
- Fix of gap when chunk has no video.
- Fix of gap when pes has failure.
- Fix of repair function - don't abort when we fail.

0.5.0
New features:
-Is now a lib and a small frontend program

Lib:
- More fixes to MPEG "fix/repairs".
- Fixes the GOP header SMTPE timestamp.
- Functions for remote indexing.
- Functions for remote retrival.
- Functions to extract images.
- Functions to make cuts.
- Plus a lot more :)

More detailed description of the milestone releases

* Demultiplex of video and audio (both MPEG and AC3/a52) from all Tivo types made - SA Tivo Series 1, SA TIVO Series 2, DTivo Series 1 and UK Tivo using software revision 1.3 and up. NOTE: DTivo Series 2 should in principle be supported but I have not yet be able to obtain a TyStream from it. Update: Yes, AC3 DTivo S2 is supported (lots of errors although harmless - MPEG audio doesn't work).
* Check and correction for when we have an overflow or underflow of frames.

* Overflow - This is more or less always a video sequence (GOP) header and corresponding I frame that is actually missing. What happens is that tydemux doesn't catch the SEQ/GOP, hence when we count frames for the SEQ/GOP it looks like an overflow. Tydemux repairs this problem by adding both SEQ, GOP, and I frame at the right location of the stream.

* Underflow - This is when one or several B or P frames is missing from the video sequence (GOP). Tydemux will repair this by inserting a B or a P frame at the appropriate location in the stream.

* Compensates for missing audio frames. This is usualy a single audio frame that's missing, but sometimes larger parts can be missing as well.

* Correction of A/V sync or drift in a TyStream. Tydemux will correct gradual drift of A/V sync. Depending on the frame rate, tydemux will mend A/V drifts of as little as 8ms, to as big as 20ms.

* Correction of temporal reference, I.E. frames out of order. Tydemux will detect any error in the temporal reference in a TyStream and mend all types of temporal reference errors that can happen.

* Audio probe. You don't need to worry about what type of audio a recording has. Tydemux will probe the whole TyStream, determine audio type, and skip to the first chunk that has that type of audio.

* TyStream repair. Tydemux will repair the TyStream if it detects holes or gaps in the stream. Up on detection of a hole or gap, tydemux will align the video and audio in such way that there is either no or very little loss of sync. Furthermore, tydemux will fix the start and end of the hole or gap in such way that the video and audio content doesn't deteriorate in quality.

* Tydemux minimizes the Audio/Video sync offset. At the end of the processing, it will tell you the offset in milliseconds.

* Large file support. Tydemux supports files over 2GB on platforms that support it.

* Correction of GOP SMTPE timestamps.

* Remote retrival/indexing.

* Cutting of the TyStream.

To Do

(NOT UP TO DATE)

0.6.0

Direct generation of single title DVD's ISO images

and so on :)

:: M a n u a l s