MKVToolnix causes file corruption in second half

[green81]

I am trying to join two video files together with MKV Toolnix.

Here are the mediainfo files for the first and second parts


1st part:

General
Unique ID : 268522462753766216628893327053354145976 (0xCA038B90A44BE5C9575671F4F1BB98B8)
Complete name : xxxxxxxxxxxxxxxxxxx.mkv
Format : Matroska
Format version : Version 4
File size : 1.45 GiB
Duration : 12 min 22 s
Overall bit rate : 16.8 Mb/s
Encoded date : UTC 2021-09-09 03:45:08
Writing application : mkvmerge v60.0.0 ('Are We Copies?') 64-bit
Writing library : libebml v1.4.2 + libmatroska v1.6.4

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 12 min 22 s
Bit rate : 16.5 Mb/s
Width : 1 920 pixels
Height : 1 064 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 59.940 (60000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.135
Stream size : 1.43 GiB (99%)
Writing library : x264 core 161 r3027 4121277
Encoding settings : cabac=1 / ref=4 / deblock=1:-3:-3 / analyse=0x3:0x133 / me=umh / subme=11 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=48 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=24 / lookahead_threads=4 / sliced_threads=0 / nr=0 / decimate=0 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=8 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=150 / rc=crf / mbtree=0 / crf=20.0 / qcomp=0.70 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=62500 / vbv_bufsize=78125 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.30 / pb_ratio=1.20 / aq=1:0.80
Language : English
Default : Yes
Forced : No

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : A_AAC-2
Duration : 12 min 22 s
Bit rate : 221 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 19.6 MiB (1%)
Default : Yes
Forced : No

2nd part:

General
Unique ID : 296390059574882479876311870158615375396 (0xDEFAA62B1DB3A7B04C92543BBDE06E24)
Complete name : xxxxxxxxxxxxxxxxxxx.mkv
Format : Matroska
Format version : Version 4
File size : 13.2 GiB
Duration : 2 h 11 min
Overall bit rate : 14.4 Mb/s
Encoded date : UTC 2021-09-10 16:13:02
Writing application : mkvmerge v60.0.0 ('Are We Copies?') 64-bit
Writing library : libebml v1.4.2 + libmatroska v1.6.4

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 2 h 11 min
Bit rate : 14.2 Mb/s
Width : 1 920 pixels
Height : 1 064 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 59.940 (60000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.116
Stream size : 13.0 GiB (98%)
Writing library : x264 core 161 r3027 4121277
Encoding settings : cabac=1 / ref=4 / deblock=1:-3:-3 / analyse=0x3:0x133 / me=umh / subme=11 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=48 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=24 / lookahead_threads=4 / sliced_threads=0 / nr=0 / decimate=0 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=8 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=150 / rc=crf / mbtree=0 / crf=19.6 / qcomp=0.70 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=62500 / vbv_bufsize=78125 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.30 / pb_ratio=1.20 / aq=1:0.80
Language : English
Default : Yes
Forced : No

Audio
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : A_AAC-2
Duration : 2 h 11 min
Bit rate : 221 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 208 MiB (2%)
Default : Yes
Forced : No


I load the first file into MKVtoolnix then right click and append the 2nd one. When I playback the resulting file it works perfectly up until the join point. After the join point the audio is fine, but the video is just a bunch of squigly lines and blurry mess. I've tried just muxing the video first. I've tried each part individually. It seems no matter how I do it it ends up the same. Not sure what I'm doing wrong.

[El Heggunte]

My suggestion: extract the video streams in their "raw" format (.264), concatenate them with the old copy /b

copy /b video1.264 + video2.264 videofull.264

,

and then remux with ffmpeg.

Reasoning: some multiplexers are not so smart as they should be. ==> https://mailman.videolan.org/pipermail/x264-devel/2013-July/010167.html

[johns0]

Try remuxing the 2 video by itself to see if there's any issues with it.

[davexnet]

A second thing to try is Avidemux, open the first, append the second

[pcspeak]

Try this.
Drag and drop both videos onto this batch file.
This will sort out problems wit B frames and open GOPS. (I hope)
Then try MKVtoolnixGUI with the newly created files.


mkvmerge DROP v10.cmd

@echo off
:loop
"C:\Program Files\MKVToolNix\mkvmerge.exe" --ui-language en --output "%~n1-New.mkv" --no-subtitles --language 0:eng --language 1:eng "%~1" --track-order 0:0,0:1 --probe-range-percentage 0.50
shift
if not %1=="" goto :loop

Cheers.

[abolibibelot]

The copy /B method suggested above seems rather crude to me, and if it works at all it's bound to cause synchronization issues.

Another thing to try is using ffmpeg with a temporary conversion to TS (transport stream). I'll copy what I already posted there earlier today.

Some years ago I struggled to find a method that would losslessly join three or four MP4 / H.264 videos with no synchronization issue. The only one that worked flawlessly was ffmpeg with a temporary TS remuxing.

ffmpeg -i "input1.mp4" -c copy -bsf h264_mp4toannexb "temp1.ts"
ffmpeg -i "input2.mp4" -c copy -bsf h264_mp4toannexb "temp2.ts"
ffmpeg -i "input3.mp4" -c copy -bsf h264_mp4toannexb "temp3.ts"
ffmpeg -i "concat:temp1.ts|temp2.ts|temp3.ts" -c copy -absf aac_adtstoasc "output.mp4"

Disclaimer : I merely copied the content of the .bat file I used back then, with an older version of ffmpeg, I'm not sure what the "-bsf h264_mp4toannexb" and "-absf aac_adtstoasc" options were for, or if they were actually necessary, or if they still exist with recent versions. Someone may chime in to elaborate on this.