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MKV to M2TS playback issues

Discussion in 'Video playback problems' started by vassock, Jun 12, 2009.

  1. vassock

    vassock Member

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    I have an MKV file. It plays fine on my PC. Unfortunately, the same is not true for my WD TV MEDIA PLAYER. It plays on the player, but with some problems. First, there appears to be a screen twitch. Then, and this is more serious, there is a sync problem with the audio and video. The audio is delayed for some reason. This does not appear to happen in PC playback. So, I used tsmuxer to convert it to M2TS (taking out the 2 DTS streams I can't hear, anyway, and leaving in 2 AC3 streams I needed). The result was a slightly smaller M2TS file.

    It played, and the sync problem appeared to be gone. Unfortunately, now the video was screwed up. It stuttered a LOT (like a youtube video during a busy time on a bad connection) and there were weird, colorful pixels all over the place. Now, the player plays the files from an external HD connected via USB. I thought that maybe it was because it was too slow, but after checking the filesize, the resulting size was around 10GB, which is less than the 11GB file when I started out (obviously due to the two DTS streams I left out).

    So, I really have no clue what to do. I do believe that I have successfully played other MKV files on that player, so I don't really understand what the problem is. I also tested a full-fledged BluRay M2TS (much bigger if I remember correctly) and it played just fine. Patching to the latest pre-release from WD didn't help. Apparently, this compatibility problem appeared a few firmware updates ago and hasn't been fixed yet (even though the pre-release is specifically labeled as something that fixes numerous MKV issues).
     
  2. davexnet

    davexnet Active member

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    It's 10GB but how long does it run - 90 minutes?
    Perhaps the data rate (kb p/s) is too high for your device
    and/or the USB has a problem with it.

    Do you have any comparable files that play OK ?

     
  3. vassock

    vassock Member

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    Yeah. The same video, but in MKV format. Runs fine, except for sound delay.
     
  4. davexnet

    davexnet Active member

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    using mkvtoolnix/mkvmerge, you may be able to remux the MKV
    and fix the audio delay.
     
  5. vassock

    vassock Member

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    The audio delay is not a problem with the file, but with the file's interaction with the player. It plays fine on my PC. And it plays fine when remuxed into an M2TS on the player (as far as syncing, just not with anything else). So, it's not really a problem with the actual file's syncing.

    Are you saying I should remux it anyway?
     
  6. k00ka

    k00ka Regular member

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    Yes! you may be able to fix the delay using mkvmerge's audio delay tool..
    Use + or - to find the delay and apply it..Don't worry this will not degrade the quality, if that's what you're worried about and only takes a few minutes..
     
  7. vassock

    vassock Member

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    But that isn't the problem. The video works fine on the PC and I even think it's supposed to work fine on earlier versions of the firmware for the WDC player. The delay is introduced in the actual playback on the WDC player! Sure, I guess I could add a delay to the video (relatively) so it is too fast on the PC and just fine on the WDC player, but I was looking for a more long-term solution.
     
  8. davexnet

    davexnet Active member

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    I once had an MKV that played perfectly fine on the PC.
    But when I converted it to DVD, the audio was out of synch by about 1/2 a second, all the way through.

    There were two ways of fixing it that I could see. On the avisynth
    script used by the DVD program, I added delayaudio(), which caused the
    required correction at dvd creation time.

    A second method was to convert the original file to stereo,
    edit it a audio editor, and actually addd 1/2 a second of blank audio
    at the beginning - thus causing the rest of the file to be correct.
    I then used this file for the DVD.

    There is no "long term solution" I'm aware of.
    You didn't state if you audio is out the same amount all the way
    through, of whether it differs depending on where you are.
    Are you sure it's not caused by too high a bitrate?


     
  9. vassock

    vassock Member

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    But that's not what's happening here. The very same MKV that plays fine on the PC plays out of sync on the WD player. And the thing is, I read that previous firmware updates allowed it to play just fine! It is only now (last few versions) that it is playing with a delay. They have a pre-release update on their site that says it fixes it, but it does not. Hopefully, they will fix it by the time they release that version in a final state.

    As for whether it plays out of sync to different degrees as the movie plays on, I think it is possible. I don't know with certainty, but I think I read some comments about it (about how the movie will get better if you pause it, but then gets worse again). So no, delaying it to somehow work around the delay in the WD player wouldn't be worth it.

    The movie does play rather well if converted to AVI format. No delay, and no resyncing necessary. It's obviously a problem with that MKV container, or perhaps with the X264 format when used in MKV or M2TS.

    Right now, I'd like to figure out a way for lossless conversion into any other format (like AVI), or even perhaps placing it into a different container. I think the issue is isolated to MKV container (although some MKV apparently play just fine). So, I want to know a way to do lossless conversion to another container (or at worst, codec) which allows for multiple audio streams (the videos have multiple languages).
     
  10. vassock

    vassock Member

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    Also, I know it's not a problem with the filesize and length, since an MKV that is almost the same, but with a size of 15GB and a length of over 3 hours (I think) works without ANY problems. Other MKVs (smaller ones) have issues like a shaky video and audio delay. One difference I noticed is that the one MKV that DOES work well (the big one) only has 1 audio track. The three other MKV tested (one of which actually crashes the player while fast forwarding) each have more than 1 audio track.
     
  11. vassock

    vassock Member

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    No, remuxing with only 1 audio track didn't help. Now, does anyone know the answer to the following question?

     
  12. davexnet

    davexnet Active member

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    Have you checked to see if the mp4 container will work?
    Use YAMB or something similar to manipulate it.
     
  13. vassock

    vassock Member

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    This appears to be the most problematic. The video plays with weird graphical glitches (artifacts), the audio cannot be switched to alternate streams, and the stream that is selected is "unsupported."

    By the way, the good news is that the video "shake" is a problem with the video, since that is how it appears on my PC. Thankfully, at least THAT isn't a problem with the player.
     
    Last edited: Jun 17, 2009

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