[FFmpeg-user] splitting and concatenating file results in a different file

Jon Beyer jbeyer at gmail.com
Thu Oct 31 19:29:24 EET 2019


Let me correct me previous statement slightly.  It would appear that there
aren't three frames inserted at the beginning of chunk_001.mp4 in
concat.mp4.  There is one frame inserted there, that causes an off-by-one
error, and then I would imagine that the second and third superfluous
frames are inserted at the beginning of different chunks.  There are 14
chunks in all, so it isn't an extra frame at each chunk, as there are only
three extra frames in the concatenated file.

Thanks again,
Jon




On Thu, Oct 31, 2019 at 1:22 PM Jon Beyer <jbeyer at gmail.com> wrote:

> Thanks Carl, here is the full output from each of those commands.  Nothing
> unusual that I can see.  I have truncated the diff output, because the
> output is superfluous after those three frames are inserted after
> chunk_000.mp4.  I'll point out that the second-to-last line of the concat
> filter command appears to properly show 4,073 frames, but then when
> converting to .jpg, 4,076 frames are produced.
>
>
>
> ffmpeg -i input.mp4 -map 0 -c copy -f segment -segment_time 10
> chunk_%03d.mp4
>
> ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
>   built with Apple clang version 11.0.0 (clang-1100.0.33.8)
>   configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.1_1 --enable-shared
> --enable-pthreads --enable-version3 --enable-avresample --cc=clang
> --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include
> -I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include/darwin
> -fno-stack-check' --host-ldflags= --enable-ffplay --enable-gnutls
> --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame
> --enable-libopus --enable-librubberband --enable-libsnappy
> --enable-libtesseract --enable-libtheora --enable-libvidstab
> --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265
> --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype
> --enable-frei0r --enable-libass --enable-libopencore-amrnb
> --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp
> --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack
> --disable-indev=jack
>   libavutil      56. 31.100 / 56. 31.100
>   libavcodec     58. 54.100 / 58. 54.100
>   libavformat    58. 29.100 / 58. 29.100
>   libavdevice    58.  8.100 / 58.  8.100
>   libavfilter     7. 57.100 /  7. 57.100
>   libavresample   4.  0.  0 /  4.  0.  0
>   libswscale      5.  5.100 /  5.  5.100
>   libswresample   3.  5.100 /  3.  5.100
>   libpostproc    55.  5.100 / 55.  5.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
>   Metadata:
>     major_brand     : isom
>     minor_version   : 512
>     compatible_brands: isomiso2avc1mp41
>     encoder         : Lavf56.40.101
>   Duration: 00:02:15.84, start: 0.000000, bitrate: 5041 kb/s
>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1280x720 [SAR 1:1 DAR 16:9], 4906 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
> (default)
>     Metadata:
>       handler_name    : VideoHandler
>     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
> stereo, fltp, 128 kb/s (default)
>     Metadata:
>       handler_name    : SoundHandler
> [segment @ 0x7fb231815800] Opening 'chunk_000.mp4' for writing
> Output #0, segment, to 'chunk_%03d.mp4':
>   Metadata:
>     major_brand     : isom
>     minor_version   : 512
>     compatible_brands: isomiso2avc1mp41
>     encoder         : Lavf58.29.100
>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 4906 kb/s, 30 fps, 30 tbr, 15360 tbn,
> 30 tbc (default)
>     Metadata:
>       handler_name    : VideoHandler
>     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
> stereo, fltp, 128 kb/s (default)
>     Metadata:
>       handler_name    : SoundHandler
> Stream mapping:
>   Stream #0:0 -> #0:0 (copy)
>   Stream #0:1 -> #0:1 (copy)
> Press [q] to stop, [?] for help
> [segment @ 0x7fb231815800] Opening 'chunk_001.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_002.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_003.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_004.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_005.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_006.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_007.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_008.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_009.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_010.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_011.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_012.mp4' for writing
> [segment @ 0x7fb231815800] Opening 'chunk_013.mp4' for writing/A speed=
> 245x
> frame= 4073 fps=0.0 q=-1.0 Lsize=N/A time=00:02:15.81 bitrate=N/A speed=
> 258x
> video:81321kB audio:2137kB subtitle:0kB other streams:0kB global
> headers:0kB muxing overhead: unknown
>
>
> ffmpeg -f concat -safe 0 -i mylist.txt -c copy concat.mp4
>
> ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
>   built with Apple clang version 11.0.0 (clang-1100.0.33.8)
>   configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.1_1 --enable-shared
> --enable-pthreads --enable-version3 --enable-avresample --cc=clang
> --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include
> -I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include/darwin
> -fno-stack-check' --host-ldflags= --enable-ffplay --enable-gnutls
> --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame
> --enable-libopus --enable-librubberband --enable-libsnappy
> --enable-libtesseract --enable-libtheora --enable-libvidstab
> --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265
> --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype
> --enable-frei0r --enable-libass --enable-libopencore-amrnb
> --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp
> --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack
> --disable-indev=jack
>   libavutil      56. 31.100 / 56. 31.100
>   libavcodec     58. 54.100 / 58. 54.100
>   libavformat    58. 29.100 / 58. 29.100
>   libavdevice    58.  8.100 / 58.  8.100
>   libavfilter     7. 57.100 /  7. 57.100
>   libavresample   4.  0.  0 /  4.  0.  0
>   libswscale      5.  5.100 /  5.  5.100
>   libswresample   3.  5.100 /  3.  5.100
>   libpostproc    55.  5.100 / 55.  5.100
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf4808c00] Auto-inserting h264_mp4toannexb
> bitstream filter
> Input #0, concat, from 'mylist.txt':
>   Duration: N/A, start: 0.000000, bitrate: 3996 kb/s
>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1280x720 [SAR 1:1 DAR 16:9], 3866 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
>     Metadata:
>       handler_name    : VideoHandler
>     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
> stereo, fltp, 130 kb/s
>     Metadata:
>       handler_name    : SoundHandler
> Output #0, mp4, to 'concat.mp4':
>   Metadata:
>     encoder         : Lavf58.29.100
>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 3866 kb/s, 30 fps, 30 tbr, 15360 tbn,
> 15360 tbc
>     Metadata:
>       handler_name    : VideoHandler
>     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
> stereo, fltp, 130 kb/s
>     Metadata:
>       handler_name    : SoundHandler
> Stream mapping:
>   Stream #0:0 -> #0:0 (copy)
>   Stream #0:1 -> #0:1 (copy)
> Press [q] to stop, [?] for help
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf4808c00] Auto-inserting h264_mp4toannexb
> bitstream filter
>     Last message repeated 1 times
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf3803a00] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf3006800] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf4001400] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf4808c00] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf3802e00] Auto-inserting h264_mp4toannexb
> bitstream filter7x
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf4007000] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf3802e00] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf4808c00] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf3006800] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf400fe00] Auto-inserting h264_mp4toannexb
> bitstream filter
> [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7fecf4001400] Auto-inserting h264_mp4toannexb
> bitstream filter29x
> frame= 4073 fps=3955 q=-1.0 Lsize=   83591kB time=00:02:15.91
> bitrate=5038.4kbits/s speed= 132x
> video:81322kB audio:2137kB subtitle:0kB other streams:0kB global
> headers:0kB muxing overhead: 0.157127%
>
>
>
> ffmpeg -i input.mp4 video1/frames_%05d.jpg
>
> ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
>   built with Apple clang version 11.0.0 (clang-1100.0.33.8)
>   configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.1_1 --enable-shared
> --enable-pthreads --enable-version3 --enable-avresample --cc=clang
> --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include
> -I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include/darwin
> -fno-stack-check' --host-ldflags= --enable-ffplay --enable-gnutls
> --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame
> --enable-libopus --enable-librubberband --enable-libsnappy
> --enable-libtesseract --enable-libtheora --enable-libvidstab
> --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265
> --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype
> --enable-frei0r --enable-libass --enable-libopencore-amrnb
> --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp
> --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack
> --disable-indev=jack
>   libavutil      56. 31.100 / 56. 31.100
>   libavcodec     58. 54.100 / 58. 54.100
>   libavformat    58. 29.100 / 58. 29.100
>   libavdevice    58.  8.100 / 58.  8.100
>   libavfilter     7. 57.100 /  7. 57.100
>   libavresample   4.  0.  0 /  4.  0.  0
>   libswscale      5.  5.100 /  5.  5.100
>   libswresample   3.  5.100 /  3.  5.100
>   libpostproc    55.  5.100 / 55.  5.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
>   Metadata:
>     major_brand     : isom
>     minor_version   : 512
>     compatible_brands: isomiso2avc1mp41
>     encoder         : Lavf56.40.101
>   Duration: 00:02:15.84, start: 0.000000, bitrate: 5041 kb/s
>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1280x720 [SAR 1:1 DAR 16:9], 4906 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc
> (default)
>     Metadata:
>       handler_name    : VideoHandler
>     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
> stereo, fltp, 128 kb/s (default)
>     Metadata:
>       handler_name    : SoundHandler
> Stream mapping:
>   Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))
> Press [q] to stop, [?] for help
> [swscaler @ 0x11246b000] deprecated pixel format used, make sure you did
> set range correctly
> Output #0, image2, to 'video1/frames_%05d.jpg':
>   Metadata:
>     major_brand     : isom
>     minor_version   : 512
>     compatible_brands: isomiso2avc1mp41
>     encoder         : Lavf58.29.100
>     Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 1280x720 [SAR 1:1 DAR
> 16:9], q=2-31, 200 kb/s, 30 fps, 30 tbn, 30 tbc (default)
>     Metadata:
>       handler_name    : VideoHandler
>       encoder         : Lavc58.54.100 mjpeg
>     Side data:
>       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
> frame= 4073 fps= 72 q=24.8 Lsize=N/A time=00:02:15.76 bitrate=N/A
> speed=2.39x
> video:97113kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
> muxing overhead: unknown
>
>
> ffmpeg -i concat.mp4 video2/frames_%05d.jpg
>
> ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
>   built with Apple clang version 11.0.0 (clang-1100.0.33.8)
>   configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.1_1 --enable-shared
> --enable-pthreads --enable-version3 --enable-avresample --cc=clang
> --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include
> -I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include/darwin
> -fno-stack-check' --host-ldflags= --enable-ffplay --enable-gnutls
> --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame
> --enable-libopus --enable-librubberband --enable-libsnappy
> --enable-libtesseract --enable-libtheora --enable-libvidstab
> --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265
> --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype
> --enable-frei0r --enable-libass --enable-libopencore-amrnb
> --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp
> --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack
> --disable-indev=jack
>   libavutil      56. 31.100 / 56. 31.100
>   libavcodec     58. 54.100 / 58. 54.100
>   libavformat    58. 29.100 / 58. 29.100
>   libavdevice    58.  8.100 / 58.  8.100
>   libavfilter     7. 57.100 /  7. 57.100
>   libavresample   4.  0.  0 /  4.  0.  0
>   libswscale      5.  5.100 /  5.  5.100
>   libswresample   3.  5.100 /  3.  5.100
>   libpostproc    55.  5.100 / 55.  5.100
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'concat.mp4':
>   Metadata:
>     major_brand     : isom
>     minor_version   : 512
>     compatible_brands: isomiso2avc1mp41
>     encoder         : Lavf58.29.100
>   Duration: 00:02:15.94, start: 0.000000, bitrate: 5037 kb/s
>     Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 1280x720 [SAR 1:1 DAR 16:9], 4903 kb/s, 29.98 fps, 30 tbr, 15360 tbn, 60
> tbc (default)
>     Metadata:
>       handler_name    : VideoHandler
>     Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz,
> stereo, fltp, 128 kb/s (default)
>     Metadata:
>       handler_name    : SoundHandler
> Stream mapping:
>   Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))
> Press [q] to stop, [?] for help
> [swscaler @ 0x10ecd7000] deprecated pixel format used, make sure you did
> set range correctly
> Output #0, image2, to 'video2/frames_%05d.jpg':
>   Metadata:
>     major_brand     : isom
>     minor_version   : 512
>     compatible_brands: isomiso2avc1mp41
>     encoder         : Lavf58.29.100
>     Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 1280x720 [SAR 1:1 DAR
> 16:9], q=2-31, 200 kb/s, 30 fps, 30 tbn, 30 tbc (default)
>     Metadata:
>       handler_name    : VideoHandler
>       encoder         : Lavc58.54.100 mjpeg
>     Side data:
>       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
> frame= 4076 fps= 73 q=24.8 Lsize=N/A time=00:02:15.86 bitrate=N/A dup=3
> drop=0 speed=2.44x
> video:97160kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
> muxing overhead: unknown
>
>
>
>
> diff -r video1/ video2/
>
> Binary files video1/frames_00474.jpg and video2/frames_00474.jpg differ
> Binary files video1/frames_00475.jpg and video2/frames_00475.jpg differ
> Binary files video1/frames_00476.jpg and video2/frames_00476.jpg differ
> Binary files video1/frames_00477.jpg and video2/frames_00477.jpg differ
> Binary files video1/frames_00479.jpg and video2/frames_00479.jpg differ
> (truncated)
> Binary files video1/frames_04067.jpg and video2/frames_04067.jpg differ
> Binary files video1/frames_04068.jpg and video2/frames_04068.jpg differ
> Binary files video1/frames_04069.jpg and video2/frames_04069.jpg differ
> Binary files video1/frames_04070.jpg and video2/frames_04070.jpg differ
> Binary files video1/frames_04071.jpg and video2/frames_04071.jpg differ
> Only in video2/: frames_04074.jpg
> Only in video2/: frames_04075.jpg
> Only in video2/: frames_04076.jpg
>
>
>
>
>
> On Thu, Oct 31, 2019 at 11:32 AM Carl Eugen Hoyos <ceffmpeg at gmail.com>
> wrote:
>
>>
>>
>> > Am 31.10.2019 um 14:55 schrieb Jon Beyer <jbeyer at gmail.com>:
>> >
>> > I'm trying to understand the basics of splitting a file on I frames and
>> > then concatenating the smaller files back together.
>>
>> The fundamentals are that ffmpeg is a transcoding application, not a file
>> archiver.
>> Your command lines should provide identical output for some input files,
>> but without the command lines you tested posted together with the complete,
>> uncut console output there is not much we can say (or guess).
>>
>> Carl Eugen
>> _______________________________________________
>> ffmpeg-user mailing list
>> ffmpeg-user at ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-user
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-user-request at ffmpeg.org with subject "unsubscribe".
>
>


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