DVR-MS vs ASF difference

[Dmitry Vergheles]

Hello All,

We are trying to add DVR-MS muxing feature to our SolveigMM ASF Muxer (http://forum.doom9.org/showthread.php?t=92136&highlight=solveigmm)

There are MS filter to provide such a functionality - Stream Buffer Sinc filter, but it seems to only operate in real-time mode and is not somehow usefull for files muxing, remuxing.

Well, does anybody know what exactly the difference between DVR_MS and ASF files?

Any guesses, documentation references and existing tools quotations are highly appreciated.

[Inventive Software]

This place (http://wiki.multimedia.cx/index.php?title=Main_Page) has great documentation on just about any format. Specifically DVR-MS: http://wiki.multimedia.cx/index.php?title=DVR-MS

:)

[Dmitry Vergheles]

This place (http://wiki.multimedia.cx/index.php?title=Main_Page) has great documentation on just about any format. Specifically DVR-MS: http://wiki.multimedia.cx/index.php?title=DVR-MS

:)

Thank you:thanks: Nice resource :)

the doc says

While DVR-MS files do conform to the ASF specification there are are some unusual features that are not publicly documented. In particular the following are of note:

* Unlike in regular ASF files, the change of the media object number between video stream sub-packets does not imply that the frame has been completely read. The only way to detect the end of the video frame is to use a codec-specific process to analize the stream.

* All frames in a DVR-MS file are marked as keyframes which makes it impossible to write correct stream-seeking functions without resorting to codec specific code.

* The audio stream header in a DVR-MS file is stored in the header extension object rather than a standard stream header object. The GUID for the audio stream has never been published by Microsoft and this has made it difficult for open source programs to correctly play the format. However the GUID has now been discovered and several open sources media players are now finally capable of playing DVR-MS files.

It's god starting point. Is there any more information about difference, may be official, may be there are some open source tools to create DVR-MS?

[Inventive Software]

None that I know of. ffmpeg and mplayer I think has decoder support for DVR-MS, so have a dig through that mountain if what I've posted isn't helpful.

[Dmitry Vergheles]

None that I know of. ffmpeg and mplayer I think has decoder support for DVR-MS, so have a dig through that mountain if what I've posted isn't helpful.

Thanks again. What you've posted is very helpfull;) I'm just tryint to collect some more information :)