Ticket #492 (assigned defect)

Opened 4 years ago

Last modified 18 months ago

MKV file containing MPEG2 played via Perian is very poor quality

Reported by: jelockwood Owned by: astrange
Priority: normal Milestone: Needs Feedback From User
Component: matroska Version: 1.2
Severity: normal Keywords:


I have used MakeMKV for Mac to 'wrap' an MPEG2 video and AC3 audio source. The resulting file(s) play fine in VLC for Mac. The files will open fine in QuickTime but play with repeated smearing and/or macroblock problems.

This has been reproduced on a Mac mini running Mac OS X 10.5.8 and Perian 1.2, and a MacBook? Pro running Mac OS X 10.6.2 and Perian 1.2.1. Both machines also had the Apple MPEG2 QuickTime component installed.

See this thread  http://forums.cocoaforge.com/viewtopic.php?f=25&t=21949 for more information and also some screencaptures illustrating the problems.

Change History

comment:1 Changed 4 years ago by astrange

  • Owner set to astrange
  • Status changed from new to assigned
  • Component changed from Perian-Main to matroska
  • Milestone set to 1.3

comment:2 Changed 3 years ago by jelockwood

It is nearly a year since I reported this problem. I note that no new version of Perian has been released either in that time so I cannot accuse you of not including a fix for this but I was wondering if there was any progress on finding a solution?

Judging from the lack of comments to this TRAC entry, it would not appear to be worthwhile building a SVN version just to address this issue (as it has it appears not yet been addressed). Can you confirm this and/or provide any other feedback?

comment:3 Changed 3 years ago by astrange

I'm aware of this problem but haven't had any time to look at it. It may have fixed itself in SVN in the meantime.

comment:4 Changed 3 years ago by jelockwood

With the recent release of a new version of Perian 1.2.2 I have retested this problem.

While I don't have some of the original sample files anymore, it seems that Perian 1.2.2 has made a small improvement in that while the macro-blocking problem still occurs the smearing (on the samples I still have) is gone.

However, I also found that using MakeMKV 1.6.7 (the as of writing latest version), then files produced using 1.6.7 did not play any video at all via Perian 1.2.2 with QuickTime Player and Apple's MPEG2 component (the old samples play video with the macro-blocking). These new 1.6.7 created files do still play perfectly in VLC.

Note: Audio and subtitles do work with Perian 1.2.2 and a MakeMKV 1.6.7 produced file.

It is possible that Perian 1.2.2 needs a fix to be compatible with MakeMKV 1.6.7 files at all, which might be a separate issue to macro blocking. If this is the case and is done, it maybe (if we are lucky) that MakeMKV itself has fixed the macro blocking issue. As currently no video at all plays we cannot see if this is the case.

comment:5 Changed 3 years ago by jelockwood

Good news. (For you!)

Via another forum I came across another MKV tool for Mac called MkvToolnix? which includes MkvMerge?. I used this to merge a .M2V video file three Ac3 audio files and IDX/SUB files for the subtitles. The resulting MKV file like the ones produced using MakeMKV contained unaltered MPEG2 video therefore preserving as desired all the original quality, but this time it played perfectly in QuickTIme Player (with Perian 1.2.2).

As a check I used the same VIDEO_TS with MakeMKV and it still resulted in a bad file.

Therefore it is possible to use Perian to play an MKV file containing MPEG2 video successfully and any remaining problems are now down to MakeMKV. I have posted a message on the MakeMKV website.

Unfortunately it is a lot more work involved using the MkvMerge? approach than it would be with MakeMKV.

Both MakeMKV and MkvMerge? produce files that play fine in VLC.

comment:6 Changed 3 years ago by astrange

Maybe related to #560.

comment:7 Changed 3 years ago by gbooker

(In [1432]) Added mpeg layer 1 and 2 to compressed codec handling. Refs #492

comment:8 Changed 3 years ago by gbooker

We really need a sample file of the resulting mkv to make sure, but the above commit may fix the files which are not playable.

comment:9 Changed 18 months ago by astrange

  • Milestone changed from 1.3 to Needs Feedback From User
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