mmg problem ( The codec's private data does not match)

[Umen Pich]

Hi there,
this problem really pisses me off, because I don't see why the hell mmg complains my two files were having different video tracks. They were both encoded by AvidemuxGui (with the same parameters).
What does it mean "codec's private data" ?
Below I paste the info for both files. Even the encoding settings are the same. What else should be ?
All postings I found by searching for the same err message in this (and other) forums don't seem to be very useful.
Here is the whole message (from mkvtoolnix 4.8.0):

track number 1 from the file 718b.mkv: The codec's private data does not match (lengths: 41 and 40). Please make sure that the resulting file plays correctly the whole time. The author of this program will probably not give support for playback issues with the resulting file.

and here is the info from MediaInfo:

file 1:
General

Complete name : D:\pics\!new\Rockies 2011\mkv\718b.mkv Format : Matroska File size : 23.5 MiB Duration : 29s 533ms Overall bit rate : 6 674 Kbps Movie name : Avidemux Writing application : Lavf52.108.0 Writing library : Lavf52.108.0
Video

ID : 1 Format : AVC Format/Info : Advanced Video Codec Format profile : High@L3.1 Format settings, CABAC : Yes Format settings, ReFrames : 2 frames Muxing mode : Container profile=Unknown@3.1 Codec ID : V_MPEG4/ISO/AVC Duration : 29s 533ms Bit rate : 6 461 Kbps Width : 1 280 pixels Height : 720 pixels Display aspect ratio : 16:9 Frame rate mode : Variable Frame rate : 30.000 fps Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : 0.234 Stream size : 22.7 MiB (97%) Writing library : x264 core 115 r1947 b5a8ad7 Encoding settings : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=9 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=4 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=2 / b_pyramid=0 / b_adapt=2 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=26.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Audio

ID : 2 Format : MPEG Audio Format version : Version 2 Format profile : Layer 3 Codec ID : A_MPEG/L3 Codec ID/Hint : MP3 Duration : 29s 533ms Bit rate mode : Constant Bit rate : 80.0 Kbps Channel(s) : 1 channel Sampling rate : 22.05 KHz Video delay : -33ms Stream size : 288 KiB (1%)

***************************

and file 2:
General

Complete name : D:\pics\!new\Rockies 2011\mkv\723.mkv Format : Matroska File size : 6.92 MiB Duration : 19s 539ms Overall bit rate : 2 971 Kbps Movie name : Avidemux Writing application : Lavf52.108.0 Writing library : Lavf52.108.0
Video

ID : 1 Format : AVC Format/Info : Advanced Video Codec Format profile : High@L3.1 Format settings, CABAC : Yes Format settings, ReFrames : 2 frames Muxing mode : Container profile=Unknown@3.1 Codec ID : V_MPEG4/ISO/AVC Duration : 19s 533ms Bit rate : 2 832 Kbps Width : 1 280 pixels Height : 720 pixels Display aspect ratio : 16:9 Frame rate mode : Variable Frame rate : 30.000 fps Color space : YUV Chroma subsampling : 4:2:0 Bit depth : 8 bits Scan type : Progressive Bits/(Pixel*Frame) : 0.102 Stream size : 6.59 MiB (95%) Writing library : x264 core 115 r1947 b5a8ad7 Encoding settings : cabac=1 / ref=2 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=9 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=4 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=2 / b_pyramid=0 / b_adapt=2 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=40 / rc=crf / mbtree=1 / crf=24.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Audio

ID : 2 Format : MPEG Audio Format version : Version 2 Format profile : Layer 3 Codec ID : A_MPEG/L3 Codec ID/Hint : MP3 Duration : 19s 539ms Bit rate mode : Constant Bit rate : 80.0 Kbps Channel(s) : 1 channel Sampling rate : 22.05 KHz Video delay : -33ms Stream size : 191 KiB (3%) Writing library : LAMEЄЄ5<%
‹
ЙљхA1v`

If you wonder why don't I re-encode -- I tried without success. Plus I have about 150 files altogether and some of them are having that problem - still don't know exactly all of them, because mkvmerge finds the error starting from the last "wrong" file. Then I have to "remove all", open, append... this time without the last found "wrong" file.. start merging again... then it finds another "wrong" file... etc.

And no - it doesn't play correctly. The video gets frozen.
I have a lot of experience with mkvtoolnix and never ever seen anything like that.

Any help is highly welcome.
Thanks !

[Bjs]

Video bitrates are not the same ... dont join if they do not match exactly or enjoy problematic playback after.

[Umen Pich]

To my understanding video bitrates CAN be different for the simple reason that you can have variable bitrate in any of the pieces ?

[poisondeathray]

did you try appending in avidemux?

the files are not that big, another option is to join before encoding, this usually prevents headaches

[lovelove]

Another option is to join before encoding, this usually prevents headaches

That's what OP has been trying all along ... it's the point of this thread.

To my understanding video bitrates CAN be different for the simple reason that you can have variable bitrate in any of the pieces ?

my thoughts exactly.

I could only find these threads:
http://forum.doom9.org/showthread.php?t=129920
http://forum.doom9.org/showthread.php?t=154413
but they don't really solve the issue either.

[poisondeathray]

Another option is to join before encoding, this usually prevents headaches

That's what OP has been trying all along ... it's the point of this thread.

My understanding is that he encoded 2 separate videos with avidemux and x264 with the same parameters, then attempted to join them in mmg

They were both encoded by AvidemuxGui (with the same parameters).

Instead, if he had appended the original videos (e.g. frameserve and append with avisynth, because he is re-encoding the original videos with x264 anyways) , there would be no problem. Joining files in uncompressed domain is always more reliable than doing it after

[lovelove]

sorry, I had misunderstood you. You are right of course.
I think OP has a point though regarding VBR.