My experience all around with Mpeg4 ASP (e.g. DivX, XviD, etc…) regardless of the container in which they are muxed has been very poor with the last few firmware versions. AVIs seem to make pretty long pauses when you start/skip the video, sometimes mp4 reproduction stops when you rw/ff, and some matroska files seem to have ‘micro-stutters’. None of these happen with other codecs, thankfully. Only with the family of MPEG-4 / ASP codecs.
Even though the video you labeled “bad” seems to play well for me I would recommend a couple of generic things to help solve this issue:
*one: I would remux all Matroska files with the " --engage no_cue_duration --engage no_cue_relative_position --disable-track-statistics-tags" options as a permanent part of mmg. Unlike the option you mentioned (–engage native_mpeg4) these are perfectly safe, they just remove things that were added in versions 6 and 7 of MMG. The last one probably doesn’t have any bearing in your issue, but the first two combined ( " --engage no_cue_duration --engage no_cue_relative_position") disable the addition of cue data related to the ‘version 4’ of the Matroska format. In my experience, that data messes up the navigation of matroska files played on the WDTV, badly. Videos that skip forward 10 mins almost instantly without that extra data, take almost forever to do the same with it. It shows up in the field “Format Version” as “Version 4 / Version 2”. With these command line options it becomes simply “Version 2”, as it were with versions of mkvtoolnix prior to v6.
* two: never put an Xvid stream that has the ‘packed bitstream’ hack inside a matroska container. Those files seem to play at 10-15 fps. When in doubt, always test avi files with the application ‘mpeg4 modifier’ before muxing it, and if it has ‘packed bitstream’, unpack it. In this case your Xvid seemed to be unpacked though, so that can’t be the problem.
* three: don’t use files without audio tracks as tests: those usually have poor navigation on the WDTV. Many files that play ‘clumsily’ without audio, play perfectly fine with it.
Even then, I still have one or two files that I haven’t figured out yet why they have ‘micro-stutters’ when they are muxed in mkv but play fine in avi, so I’m guessing there are even more issues.
By the way, the differences you see in the mediainfo logs are not relevant… mediainfo shows format/codec info in slightly different ways depending on the container (MP4, avi…) because the metadata is also stored differently in them. As you say, the problem is simply how the WDTV handles those files.
