One player giving me fits with MKV files

[gatownsend]

Hi folks,

I have a bit of an obscure/odd problem that I've been wrestling with for several weeks now, and I'm at my wits end. I'm hoping someone here has some insight and can help.

My cable company provides a whole-house DVR solution, and the remote boxes at the TVs are able to play video and audio served up by a DLNA server. I have an Ubuntu 14.04 box in the basement, and I have Plex Media Server installed. Their DVR box seems to be the pickiest thing I've ever used as far as file formats, but despite creating files using the correct video and audio codecs, they still aren't playing. I'm using Vidcoder to encode, and AnyDVD HD to decrypt, and I'm converting all my Blu-rays since I don't have a blu-ray player at each TV. This worked fine for several months, but I seem to be unable to encode anything to MKV containers (my preferred container for a few reasons) for the last several months. More specifically, let me tell you what I am doing and what I'm seeing.

I've set up a preset in Vidcoder that has all the specifications that should create a file that will be played by the cable box. It worked just fine for months, and then suddenly the files stopped playing. The media player tosses up an unsupported file type for ones created the last several weeks. This is where things get strange:

1. If I use the exact same settings in Vidcoder, but change the container to an MP4, the media player will play the file. Change it back to MKV and encode it and it won't play.

2. If I only encode 5 or 6 chapters to create a small test file, that MKV file will play. If I go back and encode the entire movie the resulting MKV will not play (no other settings changed except number of chapters to include).

3. Tonight for laughs I remuxed one of the non-playing MKVs made by Vidcoder using MKVtooknix. That MKV file from MKVtoolnix will play (at this point I have a major WTF moment).

4. I just compared the MKV created by Vidcoder to the one created when I remuxed the file using MKVtoolnix. The differences are so tiny, but here they are (I've only listed the differences:

File size:

Vidcoder: 8,441,787,677 bytes
MKVtooknix: 8,440,267,287 bytes

Format version:

Vidcoder: Version 2
MKVtooknix: Version 4 / Version 2

Overall bit rate:

Vidcoder: 8034 kbps
MKVtooknix: 8033 kbps

Video bit rate:

Vidcoder: 7234 kbps
MKVtooknix: 7233 kbps

Audio delay relative to video:

Vidcoder: 27ms
MKVtooknix: -5ms

Aside from the above, the only things different between the two files is the Writing Application and some lines that MVKtoolnix appears to have added, which I pasted in below:

DURATION : 02:20:05.876000000
NUMBER_OF_FRAMES : 201539
NUMBER_OF_BYTES : 7765657218
_STATISTICS_WRITING_APP : mkvmerge v7.8.0 ('River Man') 64bit built on Mar 27 2015 16:31:37
_STATISTICS_WRITING_DATE_UTC : 2015-05-05 23:35:21
_STATISTICS_TAGS : BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES

So at this point I'm at a complete loss. I even installed MediaTomb on the server last week to rule out a problem with Plex, and the same thing happens. I have a couple players that won't do MP4s, so MKV is what I'd prefer to use. I'd really like to just have the MKVs that come from Vidcoder work without having to take the extra step to remux them using MKVtoolnix, but I've been unable to come up with anything else that works. That only takes a couple minutes to do, but it's just another step in the process that makes it more cumbersome/time consuming. FWIW, these MKVs play on EVERY other player I have - just not the cable box. I'm guessing it's some quirk with the box, but I also think I have a better chance of seeing a unicorn than actually getting a firmware change to the cableco's box (assuming I can even identify a problem there and come up with a solution).

I'm all ears if anyone has any ideas.

Thanks,

Gary

[dphirschler]

Long shot, but could it be a compressed header? I only say because I've had that issue in the past.

Darryl

[gatownsend]

Long shot, but could it be a compressed header? I only say because I've had that issue in the past.

Darryl

Thanks for this. This is the best clue I've had so far, but I did some digging on this last night and don't think it's my problem. I used MediaInfo and MKVinfo to check two files (one that worked and one that didn't). I didn't see anything that lead to me believe either file has header compression. Interestingly enough, the file that plays is slightly smaller than the one that doesn't. If' I'm understanding what the header compression does, a file that has head compression should be smaller (and as I noted, my smaller file is the one that plays).

The other thing that leads me to believe this isn't the problem is that if I encode only a couple chapters that file will play. If I encode the entire movie, that file will NOT play (no other settings changed between encodes - only difference is how much was encoded). This is what has me really scratching my head. It doesn't matter which blu-ray I try, the above happens. I think I'm going to try encoding everything EXCEPT the last chapter and see if that file plays. I'm at a loss and not sure what else to try at this point.

I am open to trying anything, so any suggestions are appreciated.

Thanks,

Gary