Assertion failed!

[voidgraphics]

Hello! Thank you very much for this tool.

I seem to have a problem when running it:

untrunc -v .\WE11-3.MP4 .\WE11-4.MP4
Info: version 'ebeb1a1' using ffmpeg '3.3.4'
Info: reading .\WE11-3.MP4
Info: parsing healthy moov atom ...
Composition time offset atom found. Out of order samples possible.
ftyp_ = 'XAVC'
detected 'XAVC', deactivating 'g_strict_nal_frame_check'
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000000046bcf80] Drop frame is only allowed with 30000/1001 or 60000/1001 FPS
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '.\WE11-3.MP4':
  Metadata:
    major_brand     : XAVC
    minor_version   : 16785407
    compatible_brands: XAVCmp42iso2
    creation_time   : 2020-03-07T13:01:38.000000Z
  Duration: 01:24:02.04, start: 0.000000, bitrate: 58213 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 56422 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Video Media Handler
      encoder         : AVC Coding
    Stream #0:1(und): Audio: pcm_s16be (twos / 0x736F7774), 48000 Hz, 2 channels, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Sound Media Handler
    Stream #0:2(und): Data: none (tmcd / 0x64636D74) (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Time Code Media Handler
    Stream #0:3(und): Data: none (rtmd / 0x646D7472), 245 kb/s (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Timed Metadata Media Handler
      timecode        : 00:00:00:00
found avcC after: 102
remaining len:169
parsing avcC ...
len_sps: 52
decoding SPS ...
log2_max_frame_num: 6
avcC got decoded
assuming constant duration of 1001 for 'avc1' (x151110)
assuming constant duration of 1 for 'twos' (x242017920)
Info: special track found (tmcd, 'Time Code Media Handler')
assuming constant duration of 1001 for 'rtmd' (x151110)
Info: special track found (meta, 'Timed Metadata Media Handler')

Info: unknown track 'twos' found -> fallback to dynamic stats
created dummy track 'free'
Assertion failed!

Program: H:\untrunc_x64\untrunc.exe
File: src/mp4.cpp, Line 557

Expression: off - current_mdat_->contentStart() >= pat_size_ / 2

Do you have any ideas what might be going wrong? The reference file does play fine.

Thank you very much for your time.

[anthwlock]

The assertion fails if the very first chunk has size less than 32 bytes. I think this assertion is reasonable.. probably current_mdat_->contentStart() is wrong. Can you send me the files (reference+truncated)?

[voidgraphics]

Of course. They are rather large (over 70gb combined), what would be the best way to get them in your hands?

[anthwlock]

For the broken file just send me the first 100mb (head -c 100M)

For the healthy file, it is important that the moov atom is included in the sample. If untrunc -ia good.mp4 shows mdat before moov, please use ffmpeg -i good.mp4 -movflags faststart -c copy good2.mp4 first. Then send me the first 60mb of both good.mp4 and good2.mp4.

[voidgraphics]

mdat did show just before moov, but running the ffmpeg command seems to fail:

ffmpeg -i good.mp4 -movflags faststart -c copy good2.mp4
ffmpeg version git-2020-03-11-36aaee2 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 9.2.1 (GCC) 20200122
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 42.100 / 56. 42.100
  libavcodec     58. 75.100 / 58. 75.100
  libavformat    58. 41.100 / 58. 41.100
  libavdevice    58.  9.103 / 58.  9.103
  libavfilter     7. 77.100 /  7. 77.100
  libswscale      5.  6.100 /  5.  6.100
  libswresample   3.  6.100 /  3.  6.100
  libpostproc    55.  6.100 / 55.  6.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001a755deac80] st: 0 edit list: 1 Missing key frame while searching for timestamp: 1001
[mov,mp4,m4a,3gp,3g2,mj2 @ 000001a755deac80] st: 0 edit list 1 Cannot find an index entry before timestamp: 1001. [mov,mp4,m4a,3gp,3g2,mj2 @ 000001a755deac80] Drop frame is only allowed with 30000/1001 or 60000/1001 FPS
Guessed Channel Layout for Input Stream #0.1 : stereo
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'good.mp4':
  Metadata:
    major_brand     : XAVC
    minor_version   : 16785407
    compatible_brands: XAVCmp42iso2
    creation_time   : 2020-03-07T13:01:38.000000Z
  Duration: 01:24:02.04, start: 0.000000, bitrate: 58213 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 56422 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Video Media Handler
      encoder         : AVC Coding
    Stream #0:1(und): Audio: pcm_s16be (twos / 0x736F7774), 48000 Hz, stereo, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Sound Media Handler
    Stream #0:2(und): Data: none (tmcd / 0x64636D74) (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Time Code Media Handler
    Stream #0:3(und): Data: none (rtmd / 0x646D7472), 245 kb/s (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Timed Metadata Media Handler
      timecode        : 00:00:00:00
[mp4 @ 000001a756c0cac0] Could not find tag for codec pcm_s16be in stream #1, codec not currently supported in container
Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
    Last message repeated 1 times

It does create the good2.mp4 file, but it is empty (0 bytes).

Here are the first 60mb of the good file, and the first 100mb of the bad file.

Thanks again for your help.

[anthwlock]

Try to use .mov as extension for the output file. If this still fails, you can try untrunc -ms good.mp4. It creates a file good.mp4_streamable.mp4, for the same purpose.

[voidgraphics]

Using .mov worked! Here is the file: https://send.firefox.com/download/feca220533780d84/#O7q80OTxOvzUSd50Xx14UQ

[anthwlock]

It says This link has expired. Maybe send me an email or increase download-limit?

[voidgraphics]

https://www.dropbox.com/s/0h4nn676qktmkjy/good2-60M.mov?dl=0

[voidgraphics]

Have you had a chance to take a look at it? Sorry to bother. I'll make use of your PayPal link to thank you properly for your help, if that's okay.

[anthwlock]

Will look into it soon, is it time critical for some reason?

[voidgraphics]

Nothing super crazy, but I do have a rather large crowd of people waiting for their studying material 😄

I have donated a little something to thank you for your help thus far. I do think your open source tool is a godsend - all solutions I have found were super expensive. I can't afford much but I will try to donate again if you can help at least point me in the right direction so I can get this video to these people.

Cheers 👍

[anthwlock]

Thank you! it looks like ffmpeg shuffles the streams in such a way that original chunk sizes get lost. So can you just send me the last ~10mb of good.mp4? Please post (or send me) the output of untrunc -v -i good.mp4

[voidgraphics]

untrunc -v -i good.MP4
Info: version 'ebeb1a1' using ffmpeg '3.3.4'
Info: reading good.MP4
Info: parsing healthy moov atom ...
Composition time offset atom found. Out of order samples possible.
ftyp_ = 'XAVC'
detected 'XAVC', deactivating 'g_strict_nal_frame_check'
[mov,mp4,m4a,3gp,3g2,mj2 @ 00000000045fc880] Drop frame is only allowed with 30000/1001 or 60000/1001 FPS
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'good.MP4':
  Metadata:
    major_brand     : XAVC
    minor_version   : 16785407
    compatible_brands: XAVCmp42iso2
    creation_time   : 2020-03-07T13:01:38.000000Z
  Duration: 01:24:02.04, start: 0.000000, bitrate: 58213 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 56422 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Video Media Handler
      encoder         : AVC Coding
    Stream #0:1(und): Audio: pcm_s16be (twos / 0x736F7774), 48000 Hz, 2 channels, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Sound Media Handler
    Stream #0:2(und): Data: none (tmcd / 0x64636D74) (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Time Code Media Handler
    Stream #0:3(und): Data: none (rtmd / 0x646D7472), 245 kb/s (default)
    Metadata:
      creation_time   : 2020-03-07T13:01:38.000000Z
      handler_name    : Timed Metadata Media Handler
      timecode        : 00:00:00:00
found avcC after: 102
remaining len:169
parsing avcC ...
len_sps: 52
decoding SPS ...
log2_max_frame_num: 6
avcC got decoded
assuming constant duration of 1001 for 'avc1' (x151110)
assuming constant duration of 1 for 'twos' (x242017920)
assuming constant duration of 1001 for 'rtmd' (x151110)

tracks:
  [0] vide by 'Video Media Handler' (avc1) <video, h264>
  [1] soun by 'Sound Media Handler' (twos) <audio, pcm_s16be>
  [2] tmcd by 'Time Code Media Handler' (tmcd) <data, none>
  [3] meta by 'Timed Metadata Media Handler' (rtmd) <data, none>

ftyp [0, 28]
uuid [28, 148]
mdat [184, 36687576904]
moov [36687577088, 1674672]
-mvhd "movie header" [36687577096, 108]
   Timescale: 90000 Duration: 453783600
-trak [36687577204, 1511843]
--tkhd [36687577212, 92]
     Trak: 1 Duration: 453783330
--edts [36687577304, 36]
---elst [36687577312, 28]
--mdia [36687577340, 1511655]
---mdhd "media header" [36687577348, 32]
       Timescale: 30000 Duration: 151261110
---hdlr [36687577380, 52]
    Type: vide
---minf "media information" [36687577432, 1511563]
----vmhd [36687577440, 20]
----dinf [36687577460, 36]
-----dref [36687577468, 28]
      Entries: 1
----stbl [36687577496, 1511499]
-----stsd "sample description" [36687577504, 271]
      Entries: 1 codec: avc1
-----stts "sample to decode time" [36687577775, 24]
      Entries: 1
      samples: 151110 for: 1001
-----ctts "sample to composition time" [36687577799, 805936]
-----stsc "sample to chunk" [36688383735, 28]
      Entries: 1
      chunk: 1 nsamples: 15 id: 1
-----stsz "sample to size" [36688383763, 604460]
      Sample size: 0 Entries: 151110
      Size 1513714
      Size 82180
      Size 78775
      Size 235890
      Size 96773
      Size 95161
      Size 321725
      Size 115889
      Size 114864
      Size 360632
-----co64 "chunk to offset 64" [36688988223, 80608]
      Entries: 10074
      chunk: 15556
      chunk: 4077607
      chunk: 7391297
      chunk: 10914466
      chunk: 14607055
      chunk: 18245674
      chunk: 21875817
      chunk: 25508714
      chunk: 29138083
      chunk: 32765552
-----stss "sync samples" [36689068831, 20164]
      Entries: 5037
      Keyframe: 1
      Keyframe: 31
      Keyframe: 61
      Keyframe: 91
      Keyframe: 121
      Keyframe: 151
      Keyframe: 181
      Keyframe: 211
      Keyframe: 241
      Keyframe: 271
--uuid [36689088995, 52]
-trak [36689089047, 81092]
--tkhd [36689089055, 92]
     Trak: 2 Duration: 453783600
--edts [36689089147, 36]
---elst [36689089155, 28]
--mdia [36689089183, 80904]
---mdhd "media header" [36689089191, 32]
       Timescale: 48000 Duration: 242017920
---hdlr [36689089223, 52]
    Type: soun
---minf "media information" [36689089275, 80812]
----smhd [36689089283, 16]
----dinf [36689089299, 36]
-----dref [36689089307, 28]
      Entries: 1
----stbl [36689089335, 80752]
-----stsd "sample description" [36689089343, 52]
      Entries: 1 codec: twos
-----stts "sample to decode time" [36689089395, 24]
      Entries: 1
      samples: 242017920 for: 1
-----stsc "sample to chunk" [36689089419, 40]
      Entries: 2
      chunk: 1 nsamples: 24024 id: 1
      chunk: 10074 nsamples: 24168 id: 1
-----stsz "sample to size" [36689089459, 20]
      Sample size: 4 Entries: 242017920
-----co64 "chunk to offset 64" [36689089479, 80608]
      Entries: 10074
      chunk: 3966151
      chunk: 7279841
      chunk: 10803010
      chunk: 14495599
      chunk: 18134218
      chunk: 21764361
      chunk: 25397258
      chunk: 29026627
      chunk: 32654096
      chunk: 36286029
--uuid [36689170087, 52]
-trak [36689170139, 490]
--tkhd [36689170147, 92]
     Trak: 3 Duration: 453783330
--edts [36689170239, 36]
---elst [36689170247, 28]
--mdia [36689170275, 302]
---mdhd "media header" [36689170283, 32]
       Timescale: 30000 Duration: 151261110
---hdlr [36689170315, 56]
    Type: tmcd
---minf "media information" [36689170371, 206]
----nmhd [36689170379, 12]
----dinf [36689170391, 36]
-----dref [36689170399, 28]
      Entries: 1
----stbl [36689170427, 150]
-----stsd "sample description" [36689170435, 50]
      Entries: 1 codec: tmcd
-----stts "sample to decode time" [36689170485, 24]
      Entries: 1
      samples: 1 for: 151261110
-----stsc "sample to chunk" [36689170509, 28]
      Entries: 1
      chunk: 1 nsamples: 1 id: 1
-----stsz "sample to size" [36689170537, 20]
      Sample size: 4 Entries: 1
-----stco "chunk to offset" [36689170557, 20]
      Entries: 1
      chunk: 192
--uuid [36689170577, 52]
-trak [36689170629, 81085]
--tkhd [36689170637, 92]
     Trak: 4 Duration: 453783330
--tref [36689170729, 20]
---cdsc [36689170737, 12]
--edts [36689170749, 36]
---elst [36689170757, 28]
--mdia [36689170785, 80877]
---mdhd "media header" [36689170793, 32]
       Timescale: 30000 Duration: 151261110
---hdlr [36689170825, 61]
    Type: meta
---minf "media information" [36689170886, 80776]
----nmhd [36689170894, 12]
----dinf [36689170906, 36]
-----dref [36689170914, 28]
      Entries: 1
----stbl [36689170942, 80720]
-----stsd "sample description" [36689170950, 32]
      Entries: 1 codec: rtmd
-----stts "sample to decode time" [36689170982, 24]
      Entries: 1
      samples: 151110 for: 1001
-----stsc "sample to chunk" [36689171006, 28]
      Entries: 1
      chunk: 1 nsamples: 15 id: 1
-----stsz "sample to size" [36689171034, 20]
      Sample size: 1024 Entries: 151110
-----co64 "chunk to offset 64" [36689171054, 80608]
      Entries: 10074
      chunk: 196
      chunk: 4062247
      chunk: 7375937
      chunk: 10899106
      chunk: 14591695
      chunk: 18230314
      chunk: 21860457
      chunk: 25493354
      chunk: 29122723
      chunk: 32750192
--uuid [36689251662, 52]
-uuid [36689251714, 46]
meta [36689251760, 1514]

created dummy track 'free'
Assertion failed!

Program: H:\untrunc_x64\untrunc.exe
File: src/mp4.cpp, Line 557

Expression: off - current_mdat_->contentStart() >= pat_size_ / 2

[voidgraphics]

And here is the last 10mb https://www.dropbox.com/s/ita4gobp3v14n1y/good-tail-10M.mp4?dl=0

[anthwlock]

Hope it works now. The very first chunk was indeed too small, a tmcd with 4 bytes. With the current solution the tmcd of the broken file is not recovered, but I don't think it is a problem.

[voidgraphics]

Thank you, it works!