Demuxing a "broken" mkv?

[fernandopcg]

Hi everybody, I have several MKV files which I want to remux to a M4V file so I can play them in Quicktime and iOS devices. The problem is that when I do this, using iFlicks (Which also adds some metadata about the movies) the resulting movie has either audio out of sync, the program crashes and results in a ~400MB, 20 minute file (Instead of two hour and 10GB), and so on.

I tried to demux the files to *.h264 & .ac3 files and then mux them manually to M4v (Using Subler), but even before muxing them if I play the .h264 in VLC it plays laggy and stops, and the timer is always "0:00" as if there was a problem in the file.

Here's a sample mediainfo of one of the files with trouble:

General
Unique ID                                : 247054387582707289461419451282943196551 (0xB9DCF1BD3CB0EE0A55CF3302C51D3D87)
Complete name                            : file.mkv
Format                                   : Matroska
Format version                           : Version 2
File size                                : 5.02 GiB
Duration                                 : 1h 32mn
Overall bit rate                         : 7 747 Kbps
Movie name                               : The.Mechanic x lagartish
Encoded date                             : UTC 2011-07-05 23:55:06
Writing application                      : mkvmerge v4.8.0 ('I Got The...') creado el May 23 2011 22:30:05
Writing library                          : libebml v1.2.0 + libmatroska v1.1.0

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings, CABAC                   : Yes
Format settings, ReFrames                : 5 frames
Muxing mode                              : Header stripping
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 1h 32mn
Bit rate                                 : 6 345 Kbps
Width                                    : 1 920 pixels
Height                                   : 800 pixels
Display aspect ratio                     : 2.40:1
Frame rate mode                          : Constant
Frame rate                               : 23.976 fps
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.172
Stream size                              : 4.11 GiB (82%)
Writing library                          : x264 core 114 r1913 5fd3dce
Encoding settings                        : cabac=1 / ref=5 / deblock=1:-3:-3 / analyse=0x3:0x133 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=2 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=6 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=23.5 / qcomp=0.60 / qpmin=3 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Language                                 : English
Default                                  : Yes
Forced                                   : No

Audio #1
ID                                       : 2
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Muxing mode                              : Header stripping
Codec ID                                 : A_AC3
Duration                                 : 1h 32mn
Bit rate mode                            : Constant
Bit rate                                 : 448 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Delay relative to video                  : 25s 0ms
Stream size                              : 297 MiB (6%)
Language                                 : Spanish
Default                                  : Yes
Forced                                   : No

Audio #2
ID                                       : 3
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Mode extension                           : CM (complete main)
Format settings, Endianness              : Big
Muxing mode                              : Header stripping
Codec ID                                 : A_AC3
Duration                                 : 1h 32mn
Bit rate mode                            : Constant
Bit rate                                 : 640 Kbps
Channel(s)                               : 6 channels
Channel positions                        : Front: L C R, Side: L R, LFE
Sampling rate                            : 48.0 KHz
Bit depth                                : 16 bits
Compression mode                         : Lossy
Stream size                              : 425 MiB (8%)
Language                                 : English
Default                                  : No
Forced                                   : No

Audio #3
ID                                       : 4
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 3
Muxing mode                              : Header stripping
Codec ID                                 : A_MPEG/L3
Codec ID/Hint                            : MP3
Duration                                 : 1h 32mn
Bit rate mode                            : Constant
Bit rate                                 : 160 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Stream size                              : 106 MiB (2%)
Title                                    : latin
Writing library                          : LAME3.96.1
Language                                 : Spanish
Default                                  : No
Forced                                   : No

Text #1
ID                                       : 5
Format                                   : UTF-8
Codec ID                                 : S_TEXT/UTF8
Codec ID/Info                            : UTF-8 Plain Text
Title                                    : Forzados
Language                                 : Spanish
Default                                  : Yes
Forced                                   : No

Text #2
ID                                       : 6
Format                                   : UTF-8
Codec ID                                 : S_TEXT/UTF8
Codec ID/Info                            : UTF-8 Plain Text
Language                                 : Spanish
Default                                  : No
Forced                                   : No

Text #3
ID                                       : 7
Format                                   : UTF-8
Codec ID                                 : S_TEXT/UTF8
Codec ID/Info                            : UTF-8 Plain Text
Language                                 : English
Default                                  : No
Forced                                   : No

Any ideas? Thanks!!

[Selur]

you can try if http://www.mkvrepair.com/ is able to fix your file.

[Baldrick]

Try mkv2mp4. Or are you a mac-only user?

[fernandopcg]

you can try if http://www.mkvrepair.com/ is able to fix your file.

Thanks, I'll try it right now

Try mkv2mp4. Or are you a mac-only user?

No, I have Windows too, but I prefer Mac apps (Of course if there aren't any, I have no problem on using Windows)

[fernandopcg]

Well, MKVrepair, now called Meteorite, simply crashes when trying to open a MKV file (Both "broken?" and perfectly fine), so I tried Mkv2mp4 in Windows (Very slow but I was using Parallels so that's something to expect). That did the job well, although I'll check if I can ask the program to output the separate *.h264 and *.ac3 tracks in case I need to edit them or something like that. Probably tomorrow though, it's late here and I don't want to do it now.

UPDATE: I tried MKVrepair/Meteorite in Windows too, but it doesn't fix anything, as the resulting MKV also has problems when demuxing the video track.