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• Extract individual macroblock types and their corresponding motion vectors [closed]

  14 mai 2023, par Prajit Kumar

  I need to make a pair for each macroblock from a frame of a video containing its type and motion vector.

  


  I extracted motion vectors by using the python module of mv-extractor.

  


  For macroblock type I used ffmpeg command : ffmpeg -threads 1 -debug 'mb_type' -i file.h264 -f null -

  


  The info received from ffmpeg command doesn't match with the location of motion vectors extracted (Macroblocks which are divided into smaller blocks of size 8X16 or 16X8 do not match with the info of macroblock size received in motion vector info). Also, the ffmpeg command for extracting macroblock type doesn't work properly on some videos.

  


  Can you please tell a more streamlined way of doing this task.

  


• Ffmpeg error splitting into individual encoded frames

  19 avril 2021, par Vainmonde De Courtenay

  I have a folder of .png images I wanted to make a series of .h264 frames (one frame per .png). The frames are named frame001.png, frame002.png, ...

  


  First inside the folder containing the .png files I ran

  


  ffmpeg -r 10 -i frame%3d.png -codec libx264 -r 10 video.h264 -y


  


  which did its job, generating one video.h264. But now I want to divide that into many smaller .h264 files. Following this advice I tried

  


  ffmpeg -i video.h264 -f image2 -vcodec copy -bsf h264_mp4toannexb frame%03d.h264


  


  but I hit error

  


  [image2 @ 0x55d2fc1f7b20] Application provided invalid, non monotonically increasing dts to muxer in stream 0: -2 >= -2


  


  Full console debug :

  


  # ffmpeg -i video.h264 -f image2 -vcodec copy -bsf h264_mp4toannexb fr%03d.h264
ffmpeg version 3.4.8-0ubuntu0.2 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --prefix=/usr --extra-version=0ubuntu0.2 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-librsvg --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 78.100 / 55. 78.100
  libavcodec     57.107.100 / 57.107.100
  libavformat    57. 83.100 / 57. 83.100
  libavdevice    57. 10.100 / 57. 10.100
  libavfilter     6.107.100 /  6.107.100
  libavresample   3.  7.  0 /  3.  7.  0
  libswscale      4.  8.100 /  4.  8.100
  libswresample   2.  9.100 /  2.  9.100
  libpostproc    54.  7.100 / 54.  7.100
Input #0, h264, from 'video.h264':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: h264 (High 4:4:4 Predictive), yuv444p(progressive), 480x852, 10 fps, 10 tbr, 1200k tbn, 20 tbc
Output #0, image2, to 'fr%03d.h264':
  Metadata:
    encoder         : Lavf57.83.100
    Stream #0:0: Video: h264 (High 4:4:4 Predictive), yuv444p(progressive), 480x852, q=2-31, 10 fps, 10 tbr, 10 tbn, 10 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
[image2 @ 0x55d2fc1f7b20] Application provided invalid, non monotonically increasing dts to muxer in stream 0: -2 >= -2
frame=   28 fps=0.0 q=-1.0 Lsize=N/A time=00:00:02.50 bitrate=N/A speed=1.58e+03x    
video:142kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown


  


  I have tried the problem with multiple videos and the same thing. In fact when I check, the new files do appear. But they aren't really .h264's (just a few bytes large - appear to be ghost files) and I'm guessing this is down to the error displayed above.

  


• Separate simultaneously changing regions of video into individual videos

  17 juillet 2019, par Elle Fie

  Given a single video stream (up to 4K resolution), where only small displayed portions may change, I’d like to identify these changing sections and create separate video streams, one for each changing section of the input video stream, in real time.

  Note that this is spatial extraction, not time slicing !

  Q1 : Is there a better name to address this process ?

  Q2 : Is this an already solved problem ?

  It seems ImageMagick’s Compare program supports diffing two images, which I can process to identify regions as coordinates for an ffmpeg crop (launched in parallel for each discovered diff region), but this method relies on having a PNG stream to avoid false positive diffs due to lossy encoding. Also, too slow to happen in real time.

  Q3 : Is there any way ffmpeg can dump out the causal regions influencing scene-change detection ?