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  1. Member
    Join Date: Aug 2009
    Location: Canada
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    I'm working with some DTS audio, converting it to AC3 within an MKV container via MeGUI without touching the video, and I'm having unique issue. Every couple of files, I'll hit a random dud where it will encode about 80% of the DTS track to AC3, and then the rest will be silence. Seemingly happens at random. Choosing different decoders and settings doesn't alleviate the issue.

    Any ideas?
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  2. I'm not 100% clear on the process you're using, but are you converting the audio without first extracting it from the MKV file? Are you using the audio encoding section, OneClick, or AutoEncode? I'd guess you're using the OneClick encoder given it has an option not to encode the video but I don't use OneClick myself so I'm not certain on exactly how it does things. Anyway......

    If you don't have it installed already, MKVCleaver is an easy to use program for extracting streams from MKVs. Open an MKV and select the audio stream, then get MKVCleaver to extract it. If you open a bunch of MKVs you can batch extract by selecting the appropriate streams in the right pane first. Load an extracted dts file into MeGUI's audio section and encode it. Chances are that'll work perfectly.

    MKVCleaver requires MKVToolNix to work. It's in MeGUI's Tools/mkvmerge folder. Telling MKVCleaver to find it there shouldn't be a problem.

    You could no doubt replace the dts audio with the newly encoded AC3 version a couple of ways using MeGUI, but in my opinion you can't beat MKVMergeGUI (it's mmg.exe in MeGUI's Tools/mkvmerge folder).

    Maybe before any of that, you could try remuxing one of the "problem" MKVs with MKVMergeGUI first and using the new version as the input for MeGUI. If the original muxing is causing an issue for some reason that might fix the problem. Or there's other programs capable of converting either the audio or video while copying the other. FFCoder and Video To Video Converter have copy options for both. I don't use the latter for encoding much but it's a handy program to have around for "odd jobs" other programs can't do.
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  3. Member
    Join Date: Sep 2007
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    What does "seemingly happens at random" mean ?

    If you encode the same file twice with the same configuration, same settings etc... is the part with silence exactly the same ? ie. is the error repeatable ? or does the "random" component refer to "random" files ?
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  4. Member
    Join Date: Aug 2009
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    Originally Posted by hello_hello View Post
    I'm not 100% clear on the process you're using, but are you converting the audio without first extracting it from the MKV file? Are you using the audio encoding section, OneClick, or AutoEncode? I'd guess you're using the OneClick encoder given it has an option not to encode the video but I don't use OneClick myself so I'm not certain on exactly how it does things. Anyway......

    If you don't have it installed already, MKVCleaver is an easy to use program for extracting streams from MKVs. Open an MKV and select the audio stream, then get MKVCleaver to extract it. If you open a bunch of MKVs you can batch extract by selecting the appropriate streams in the right pane first. Load an extracted dts file into MeGUI's audio section and encode it. Chances are that'll work perfectly.

    MKVCleaver requires MKVToolNix to work. It's in MeGUI's Tools/mkvmerge folder. Telling MKVCleaver to find it there shouldn't be a problem.

    You could no doubt replace the dts audio with the newly encoded AC3 version a couple of ways using MeGUI, but in my opinion you can't beat MKVMergeGUI (it's mmg.exe in MeGUI's Tools/mkvmerge folder).

    Maybe before any of that, you could try remuxing one of the "problem" MKVs with MKVMergeGUI first and using the new version as the input for MeGUI. If the original muxing is causing an issue for some reason that might fix the problem. Or there's other programs capable of converting either the audio or video while copying the other. FFCoder and Video To VideoConverter have copy options for both. I don't use the latter for encoding much but it's a handy program to have around for "odd jobs" other programs can't do.

    You assumed correctly in that I'm using OneClick. I've got MKXtoolnix and MKVCleaver, but I like encoding via OneClick for a couple reasons: 1) cuts out the extra steps of de- and re-muxing; 2) allows me to batch convert very easily.


    I tried the remux of the problem file, and it didn't alleviate the issue; same result. I've converted the same file to AC3 with Popcorn MKV AudioConverter, so I have a working solution, but I can't batch encode with Popcorn, so I'd like to see if I can resolve this MeGUI issue rather painlessly.


    Originally Posted by poisondeathray View Post
    What does "seemingly happens at random" mean ?

    If you encode the same file twice with the same configuration, same settings etc... is the part with silence exactly the same ? ie. is the error repeatable ? or does the "random" component refer to "random" files ?

    Sorry, lacked a lot of specifics in my first post. Tossed up it late last night before bed, just to get the party started.


    Seemingly at random = random files that will be affected. No pattern that I can discern as to which file is affected. Encoded the same file with the same specifications and the error is repeatable. So the randomness is limited to which file it chooses to affect.
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  5. In your original post you said "it will encode about 80% of the DTS track to AC3, and then the rest will be silence", which I took literally, but are you sure 20% of the encoded file is silence, or is 20% of it missing? ie is the encoded audio only 80% the length of the original?

    To be honest unless the log file points to something obvious, I've not got any particularly clever ideas.
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  6. Member
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    Hmmm, good look. Extracted the audio file for one problem track, and it's missing about 40 minutes of audio to complete the movie.

    I encoded another file that worked and compared the logs: both complete successfully (according to the log) and I can't notice any kind of difference between the two. My eyes are not the most trained, obviously, but regardless I see little.
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  7. Unfortunately as I don't use OneClick I've still not got many clever ideas, plus I don't convert audio with MeGUI much. I tend to use foobar2000 instead. It sounds like the decoding is coming to an end prematurely but the encoder doesn't know, so everything appears to have completed successfully.

    In the audio encoder setup, there's a drop down list of preferred decoders at the top. I think MeGUI tries the preferred decoder first, then if that doesn't work it moves onto tying the next one etc. I'm pretty sure NicAudio is the default. Try selecting another one. FFVideoSource might be the next best bet. I don't know why it's happening, but hopefully it'll stop.

    Failing that, the two programs I linked to earlier (ffcoder or video to video converter) can both re-encode the audio while copying the video and both can do batch encoding.
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  8. Member
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    In the OneClick I can choose a preferred decoder as well. I already ran through them all, getting the same result.

    It seems that I've got a solution in place to get around the issue. Perhaps I'll give one of your recommend programs a shot as well. Anything to keep the ease of my batch function. I'll still tinker around and see what I come up with.


    Thanks!
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  9. Member
    Join Date: Aug 2009
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    Hopefully you're still keeping tabs on this hello_hello, but I've found something rather interesting. It would seem that the "sporadic" nature of the failures I've mentioned is not so sporadic. I'd noticed that it was only happening with very long files, so I looked into a bit more. I've found that every time the audio stops encoding, it's at the 2:04:16 mark, or 124m 16s, or 7456 seconds.

    Any thoughts? I'm planning on reformatting in the next week, so I'll see if something wonked up at some point.
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  10. Sorry, no thoughts there.

    If you're willing to brave it, and you have the patience assuming you're not already a member (they make you wait five days after registering before you're allowed to post) there's a couple of MeGUI threads over at Doom9 where the guys who maintain it hang out. That's about the only reason I post at Doom9 these days.... to report MeGUI bugs or beg for new features.... given the forum moderation takes most of the fun out of it.... but the MeGUI developers are very helpful. If you report a bug and they can replicate it, it's usually fixed in a day or two, or they'll get you to upload a sample of a "problem file" if need be etc.

    Other than that.... I'll see if I can dig out a long movie containing dts later and try converting the audio to see if the same thing happens. If I can find a lengthy enough dts file and anything exciting comes out of it, I'll let you know.

    A year or so ago, MeGUI couldn't mux MP4s running MeGUI on this PC. Rolling back to an earlier version of mp4box fixed it, yet MeGUI running on another virtually identical PC here could mux MP4s using the latest mp4box. I never did work out why, but eventually this PC went back to behaving itself after a reformat. Except for SpeedFan.... I'm fairly sure one of the 100 or so patches and fixes Windows Update installed for XP is messing with it.
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  11. Member
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    Suppose it's better late than never to update this:

    After a reformat (and about 4 months of updates) this issue has still not resolved itself. Which is disappointing, but not the end of the world. I've decided to use Popcorn MKV AudioConverter for an files that exceed the 2:04:16 mark. Popcorn does have a batch convert feature, and I can leave the video untouched, so it works out in the end.
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