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  1. Member
    Join Date: Oct 2007
    Location: United Kingdom
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    Hey all,

    I have a few MKV files are they are a little out of sync (the audio is a bit behind).

    Ive spent a few hours looking around for information and so far ive been able to split the audio and video into seperate files. (using MKVExtractGUI)

    my eventual aim will be to burn these onto DVD (I usually use DVDStyler to create a menu etc)

    Now im a little lost on what to use and how to get these files back into 1 viewable file so that the audio is in sync.

    I used VideoInspector to get some info about the MKV file:

    Video Codec: MPEG4 ISO Advanced
    Audio Codec: Dolby(TM) AC3
    Audio Sample Rate: 48000 Hz

    After splitting the audio and video I got the resulting files:

    00_Track1.h264
    00_Track2.ac3
    00_Chapters.txt (blank file)

    Im not too sure where to go from here so any help would be much appreciated

    Thanks,
    Colin-uk
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  2. I'm a MEGA Super Moderator Baldrick's Avatar
    Join Date: Aug 2000
    Location: Sweden
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    You could convert the mkv/h264 to dvd mpeg using avisynth and quenc or hc encoder. Then use delaycut to cut the ac3 in the beginning(the amount that it's behind). Add the mpg/m2v video and the ac3 in dvd styler.

    Or use delaycut to cut the ac3 in the beginning(the amount that it's behind). Mux it back to the mkv. Convert the mkv to dvd with a converter that supports mkv.

    But if the h264 has Variable Frame Rate I guess you will get major sync problems after you converted to mpg.
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  3. Member
    Join Date: Oct 2007
    Location: United Kingdom
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    Thanks for the reply Baldrick

    What would be a good util for muxing it back to mkv?
    How do i tell if its a Variable Frame Rate, and what would I do if it was?

    Sorry for the noob questions :P
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  4. i have this problem as well, except, when i play it through VLC player is syncs perfectly, but when i demux it using MKVExtractGUI and analyzed both video and audio streams i found that the audio stream itself is slightly shorter than its counterpart.

    it is also when i (did not know this) convert both files for a DVD and compiled them when authoring them, i found it was or going out of sync.

    is there a way to fix this?
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  5. Member MysticE's Avatar
    Join Date: Nov 2003
    Location: United States
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    I had various audio sync problems when I first started using FAVC. Installing ffdshow fixed it.
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  6. i have ffdshow myself but it has nothing to do with the audio stream itself which runs slightly shorter i believe.
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  7. Member
    Join Date: Dec 2007
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    Originally Posted by Undead Sega
    i have ffdshow myself but it has nothing to do with the audio stream itself which runs slightly shorter i believe.
    I have been dealing with the same problem. When I rip the audio and video tracks from the mkv, with the video as h264 and the audio as just about anything, the audio stream is always shorter than the video stream. As long as the file is left in the mkv wrapper everything is fine, even if I rip out the audio and encode it as something else and the add it back to the mkv. But, as soon as I try to rip the audio and video and then mux them into an mp4 the audio loses sync. I would kill for some help on this cause I have been messing with it for a while now and have hit a brick wall.
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  8. Member MysticE's Avatar
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    Location: United States
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    Originally Posted by Undead Sega
    i have ffdshow myself but it has nothing to do with the audio stream itself which runs slightly shorter i believe.
    I have run many MKVs through FAVC. I've checked a few with MediaInfo and the video vs. audio lengths many times are different. I just tried one that didn't match, it came out fine when encoding with FAVC/HCenc using ffdshow and Haali splitter. You can also tick Mixer in ffdshow and end up with 6 channel sound.
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  9. but tha still does not help, because it does not solve the problem with the fact that one of the streams is shorter than the other thus creating a a/v syncing issue. and besides of that application there are other we would use to authoer or merge the streams back but as another format, i.e. DVD.
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  10. Member MysticE's Avatar
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    Location: United States
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    Originally Posted by Undead Sega
    but tha still does not help, because it does not solve the problem with the fact that one of the streams is shorter than the other thus creating a a/v syncing issue. and besides of that application there are other we would use to authoer or merge the streams back but as another format, i.e. DVD.
    I'm confused. I just did an MKV where the lengths were different and the conversion to DVD was in sync. No a/v syncing issues.
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  11. but you are also claiming of using FAVC which is not my method of compiling a DVD. My method is taking both streams, the video encoded to a DVD compilant .m2v file, and the audio stream transcoded to a DVD compilant ac3 file and from there i would use DVD-lab Pro 2 to author or compile them to a DVD. It is from there i see syncing issues, but even before that when analyzing the files, they are of diferent lengths.
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  12. Member
    Join Date: Dec 2008
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    Originally Posted by WascallyWabbit
    Originally Posted by Undead Sega
    i have ffdshow myself but it has nothing to do with the audio stream itself which runs slightly shorter i believe.
    I have been dealing with the same problem. When I rip the audio and video tracks from the mkv, with the video as h264 and the audio as just about anything, the audio stream is always shorter than the video stream. As long as the file is left in the mkv wrapper everything is fine, even if I rip out the audio and encode it as something else and the add it back to the mkv. But, as soon as I try to rip the audio and video and then mux them into an mp4 the audio loses sync. I would kill for some help on this cause I have been messing with it for a while now and have hit a brick wall.
    I've been trying to solve this problem for a few days and I think the splitter is to blame. I have some MKV files with h264 video and ogg audio. They play fine in Mplayerc (with ffdshow) and VLC but every software I've tried to convert the MKV to avi - either manually, step by step, or using an integrated tool- failed. Some programs just can't work with the streams (for example Vdub can't open an "elementary" h264 file after I've demuxed the mkv and if I load the mkv wronlgy reports it as having errors) or -for the rest of them- the audio was completeley out of sync.
    It seems that mkvextract relies on the spliter currently active in the system. I had the matroska splitter active and I think the frame rate was reported wrong (23,976). Using klite codec teak tool I've disable the original matroska splitter (even on matroska.org site they addmit "it has some bugs") and then Haali spliter (recommended by cccp-projet too) became the active one. Now the frame rate is reported 30,000 fps. (I was looking also for a tool that checks for variable frame rate but I don't think this is the case). Then I've picked megui from the pile of dosen of programs installed recenlty and finally i had an avi with sinc'ed AC3 and xvid video. IT's just that this megui think creates first an avisynth script then does the actual demuxing, converting and remuxing. It takes a little too long for my taste and why the hell does it need a script? I am still looking for a better alternative, but if I can't find anything else, this will do the job.

    A few more things (later edit):
    1. during the playback of the mkv/h264 file with matroska splitter active, watching the info section in ffdshow video config window i see a continuously variable frame rate
    while with haali splitter it is fixed
    2. the h264 file that mkvextractgui outputs is CORRUPT. No matter what sofware I tried to play it, after the first few good second it goes crazy with colors all over the screen.
    Also, I don't understand why the system needs a mpeg spliter (or demultiplexer) to play a h264 file. Using graphedit and regsrvgui I've messed with various splitters (Mainconcept multiplexer was default but the problem is the same in Ulead mpleg splitter). Also I've tried changing from ffmpeg h264 to core avc codec and another one (i think ulead h264 decoder) but the file is corrupt in all of them.
    After disabling matroska splitter and activating haali splitter i've done a new run of mkvextractgui but the h264 file is still corrupt.
    Also, I've noticed the option to save a timecode file - i did not use this first time. But even if i use it, i don't know what to do with the file. And since I suppose bsplayer or mplayerc can't load this timecode when playing the h264 file I think this might be the cause for the apparent corruption of the file (?)
    THis does not make sense, because the megui still has to demux the file somehow - right? I don't know how it does ti but the final file is not corrupt.
    3. I understand from the warning some programes gave me, that h264 "elementary" mpeg-4 avc stream cannot contain by itself the frame rate so this must be included in
    the container somehow or in a separate timecode table (?). well, since the matroska splitter was reprting the frame rate wrong (in all the programs I've checked it was 23,97) this framerate was used for the newly encoded file
    and I think the correct one was 30,000 (some programs even required the user to insert the frame rate by hand).
    4. While writing the above I've done an encoding test (MKV to AVI) using xvid4psp and agina the audio is in sync with the video
    This confirms one more thime that my problem was due to the matroska splitter -which was good enough for playback but not good enogh when demuxing the file.

    Last LATER Edit:
    from the original Seal_Exclusive_Interview[TVG00015699].mkv file (approx. 13 mb) used as test (downloaded from vuze network)
    i got
    a 19 mb xvis/ac3 file from megui with incredible good quality (compared with the later alternatives) - actually indistiguishible from the original
    or
    a 15 mb file from xvid4psp with visible lower quality although I've selected XVID 2 pass extreme profile.

    Also, my first failed tries were most of them with xvid or divx video plus vbr mp3 audio. I was wondering if maybe this was causing my problem?
    I've done a new try with megui and selected lame mp3 vbr , also did not pres the "analyse file" in the filters tab of avs script dialoge, and also did not checked "force use of direct show decoders" in the audio codec confid dialogue.
    The result is again in sync.
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  13. Member
    Join Date: Dec 2008
    Location: Europe, Far, Far Away
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    well... seems i scared you lol
    it's either because it's my first post or maybe because 'twas too long.

    nvm i junst wanted to let you know that one or two days after my previous post megui made an automatical update and after that i wasn't ablt to obtain AVI's with sync audio. I even found a temporary fix somewhere on the forum but it still didn't fix the problem.
    I've reinstalled my initial megui version but after a few varios errors related to avysinth i reached the conclusion that xvid4psp is more stable and does pretty much the same thing (while it seems a little less complex).
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  14. Member
    Join Date: Nov 2005
    Location: UK
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    I often demux audio from mkv with MKVextract GUI to recompress them to make them smaller to fit on DVD. Quite often some of the audio files ar 3 to 7 seconds shorter. And the delay is not fixed. It is stretched over the whole audio track. I have solved this issue by setting playback ratio - there is such option available in MKVmerge GUI. I put e.g. some 10001/10000 and everything fits. I assume the stretch ratio was put in the MKV file in the first place. But its lost when extracted. But I do not have proof of it. Also it does not solves the problem how to stretch the audio when it has to be converted to DVD. I use CoolEdit if its stereo, or I download lower resolution avi with the same sound if it is 5.1 sound.

    Cann't tell it's possible don't tell anything.
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  15. Member
    Join Date: Oct 2011
    Location: usa
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    I dont know if this helps but i was trying to hard burn subtitles in a video stream so i took the original MKV (flawless file) with "soft" subtitles, and re encoded it with handshake. I did this on 2 different computers with the same "handshake" encoder. On the xp machine 64 bit gateway machine running in 32 bit xp os i had audio desynch of 10 or so seconds on the encoded file. but for some reason.. windows 7 on the 6x 64 bit processor running in 64 bit mode it was a flawless handshake encode with no sync errors. So it seems with same encoder different results on different machines. Handshake is a GNU encoder that can handle mp4 and mkv's on source forge. windows 7 machine was 3x the frame rate on the encode too. MKV soft subtitles (180kb file) --> mkv burned subtitles (240kb file) ---> anyvideo (freeware) to convert to (mpg 1.3 gig file) ---> windows 7 dvd maker ---> DVD that works in any dvd player.

    in summary:

    file == mkv
    re encode mkv to mkv
    software == handshake
    64 bit x4 processor windows 7 == flawless
    64 bit x2 (in 32 bit os) winxp == severe 10+ seconds audio desynch
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