[Invalid] [2838] MKV Files with Theora won't play in Mplayer

[nexradix]

Converting to Theora video (with Vorbis audio) in an MKV container produces a file that will not play back properly in Mplayer (or MythTv's "Mythvideo" internal player, for that matter). Audio plays back fine, but the video is garbled and not remotely viewable or recognizable. VLC 0.9.9a will play back these files just fine, however. The version of mplayer I'm using is 1.02rc2, and MythTV & its MythVideo plugin is at version 0.21.0.

If I extract the audio and video streams with mkvextract, Mplayer will play both back just fine, leading me to believe the issue is related to the creation of the container itself. This is further reinforced by the fact that taking an OGV file generated by Thoggen and placing its contents into an MKV container using Mkvmerge-GUI (version 2.4.1) produces the same results -- unplayable in Mplayer, but works fine in VLC.

This issue DID NOT occur in version 0.9.3. MKV files produced by that version of Handbrake work as expected in all software players I tested.

Here is the activity log from svn2838:

http://handbrake.fr/pastebin/pastebin.php?show=901

And here is the activity log from version 0.9.3:

http://handbrake.fr/pastebin/pastebin.php?show=902

I did both tests using the exact same ISO image, the exact same title, and the exact same custom preset.

To make things more confusing, the issue does not appear using the exact same preset, and simply changing to the h.264 codec. Here's the activity log from that test:

http://handbrake.fr/pastebin/pastebin.php?show=903

I can't try recreating the MKV file using mkvmerge with the h.264 codec, as I can't seem to extract the video stream properly with mkvextract.

Any assistance with this bug would be greatly appreciated. Please let me know if there is any more info you need from me, or if any more tests should be run on my end.

[JohnAStebbins]

From your description, this must be an mplayer problem. You can create a file completely independently of HandBrake that demonstrates the problem. That makes it very unlikely that handbrake is the source of the problem. Also, I tried it with the latest svn version of mplayer and it works fine.

[nexradix]

From your description, this must be an mplayer problem. You can create a file completely independently of HandBrake that demonstrates the problem. That makes it very unlikely that handbrake is the source of the problem. Also, I tried it with the latest svn version of mplayer and it works fine.

I thought as much myself, however it occured to me that there was a chance that the issue could be caused by a change in one of the upstream packages that Handbrake (and possibly also mkvmerge) relies on. Since the issue is also present in MythTv's player, I don't think the problem is isolated to Mplayer only.

If I had to guess (and that's all it is), a new feature implimented in one of the upstream contrib packages is the cause, if it breaks backwards compatibility. If that's the case, it isn't a bug-- Mplayer and the like simply need to be updated to support the new feature.

In any case, I don't expect anyone to spend any real time on this, but if we can isolate the cause upstream I can submit a report to the relevant maintainers of Mplayer, MythTV, etc and help make sure that files from Handbrake are functional in the largest number of players possible.

[JohnAStebbins]

mkvmerge and HandBrake do not share any common upstream libraries. So the only common factors are theora and the players. My guess would be theora changed something in the video stream that conforms to spec, but was unexpected by those players. And since the most recent svn version of mplayer already works, I would assume the mplayer team is already aware of what the problem was.

[nexradix]

mkvmerge and HandBrake do not share any common upstream libraries. So the only common factors are theora and the players. My guess would be theora changed something in the video stream that conforms to spec, but was unexpected by those players. And since the most recent svn version of mplayer already works, I would assume the mplayer team is already aware of what the problem was.

Ick. I was afraid you'd say that. The issue doesn't seem to be with Theora, as Mplayer and MythTV will both play the Thoggen produced OGV made with Theora 1.1. The only thing left then would be something about the MKV container. Has the specification for Matroska changed at all recently?

Since the issue is already fixed in Mplayer svn, this issue is sounds mostly academic -- however given MythTv's super slow development time, I don't expect them to release a fix anytime soon. If I can figure out what's going on, there's hope I can get a fix created for MythTv (which is how I primarily watch content I make with Handbrake).

[JohnAStebbins]

Or you could just use x264 which has superior video quality for a given file size anyway.
Comparison: http://saintdevelopment.com/media/

[nexradix]

Or you could just use x264 which has superior video quality for a given file size anyway.

I only support formats that aren't encumbered by patents.

I'll try to compile the lastest MythTV (and MythVideo plugin) from their SVN, and will report back my findings in case anyone else is interested.

EDIT: Using the MythTV SVN build included in Ubuntu's 9.10 repos, the MKV files produced with svn2838 play as expected. I'm still not sure what the cause of the issue is with the older versions, but knowing that upstream has already fixed it in both cases is enough for me. Thanks for all the help!