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• Generating movie from python without saving individual frames to files

  31 juillet 2022, par Paul

  I would like to create an h264 or divx movie from frames that I generate in a python script in matplotlib. There are about 100k frames in this movie.

  



  In examples on the web [eg. 1], I have only seen the method of saving each frame as a png and then running mencoder or ffmpeg on these files. In my case, saving each frame is impractical. Is there a way to take a plot generated from matplotlib and pipe it directly to ffmpeg, generating no intermediate files ?

  



  Programming with ffmpeg's C-api is too difficult for me [eg. 2]. Also, I need an encoding that has good compression such as x264 as the movie file will otherwise be too large for a subsequent step. So it would be great to stick with mencoder/ffmpeg/x264.

  



  Is there something that can be done with pipes [3] ?

  



  [1] http://matplotlib.sourceforge.net/examples/animation/movie_demo.html

  



  [2] How does one encode a series of images into H264 using the x264 C API ?

  



  [3] http://www.ffmpeg.org/ffmpeg-doc.html#SEC41

  


• Using ffprobe/ffmpeg to extract individual frames and types in encode order

  24 janvier 2018, par Hélder

  I am able to extract keyframes using ffmpeg. Something like this that I have been using :

  ffmpeg -i input.mp4 -vf "select='eq(pict_type\,I)" -vsync vfr -qscale:v 2 I-thumbnails-%02d.png -vf "select='eq(pict_type\,B)" -vsync vfr -qscale:v 2 B-thumbnails-%02d.png -vf "select='eq(pict_type\,P)" -vsync vfr -qscale:v 2 P-thumbnails-%02d.png

  Now the issue is, I would like these extracted frames to be in encode order, if possible, the way they are extracted should have a timestamp or any way to know that they start in a certain sequence, example, from start to end :

  IBBBIPPB......BI

  but in a way that I can sort the frames in the encode sequence.

  I want to use this to load in python to extract motion vectors but they should all follow the encoding sequence. Any help ?

  Edit :
  Changed playback to encode sequence(or order).

• Crop individual frames of a video and then concat for output

  27 juin 2024, par Ashish Padave

  I want to Crop individual frames of a video and then concat for output. This works with 2 ffmpeg commands. The first one extracts each frame and the second concats them.
I want to get it done without the intermediate frames.

  


  Tried with the following

  


  ffmpeg  -y -i input.mp4 -filter_complex "[0:v]split=890[v0][v1][v2][v3][v4][v5];[v0]select='eq(n\,0)',setpts=PTS-STARTPTS,crop=404:720:225:0[v0]; [v1]select='eq(n\,1)',setpts=PTS-STARTPTS,crop=404:720:225:0[v1]; [v2]select='eq(n\,2)',setpts=PTS-STARTPTS,crop=404:720:225:0[v2]; [v3]select='eq(n\,3)',setpts=PTS-STARTPTS,crop=404:720:225:0[v3]; [v4]select='eq(n\,4)',setpts=PTS-STARTPTS,crop=404:720:225:0[v4]; [v5]select='eq(n\,5)',setpts=PTS-STARTPTS,crop=404:720:225:0[v5];[v0][v1][v2][v3][v4][v5]concat=n=6:v=1:a=0[outv]" -map "[outv]" -map 0:a? -c:a copy -vsync 2 output.mp4


  


  The above is an abridged version of the command. The video I am working with has 890 frames and a frame rate of 25.

  


  The output log with 890 frames is

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf59.5.100
  Duration: 00:00:35.61, start: 0.000000, bitrate: 3380 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 3246 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
Stream mapping:
  Stream #0:0 (h264) -> split
  concat -> Stream #0:0 (libx264)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
[libx264 @ 0x55963ad4b700] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 AVX512
[libx264 @ 0x55963ad4b700] profile High, level 3.0
[libx264 @ 0x55963ad4b700] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 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=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'output.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.29.100
    Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 404x720, q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
    Metadata:
      encoder         : Lavc58.54.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
frame=    3 fps=0.6 q=-1.0 Lsize=     586kB time=00:00:35.59 bitrate= 134.9kbits/s dup=0 drop=887 speed=6.73x
video:21kB audio:558kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.278277%
[libx264 @ 0x55963ad4b700] frame I:1     Avg QP:23.09  size: 17546
[libx264 @ 0x55963ad4b700] frame P:1     Avg QP:25.73  size:  2069
[libx264 @ 0x55963ad4b700] frame B:1     Avg QP:26.34  size:   845
[libx264 @ 0x55963ad4b700] consecutive B-frames: 33.3% 66.7%  0.0%  0.0%
[libx264 @ 0x55963ad4b700] mb I  I16..4:  8.4% 68.9% 22.7%
[libx264 @ 0x55963ad4b700] mb P  I16..4:  0.1%  0.6%  0.3%  P16..4: 28.5%  5.0%  3.9%  0.0%  0.0%    skip:61.6%
[libx264 @ 0x55963ad4b700] mb B  I16..4:  0.0%  0.1%  0.0%  B16..8: 29.6%  3.4%  0.3%  direct: 0.2%  skip:66.4%  L0:59.3% L1:35.6% BI: 5.1%
[libx264 @ 0x55963ad4b700] 8x8 transform intra:68.8% inter:73.3%
[libx264 @ 0x55963ad4b700] coded y,uvDC,uvAC intra: 73.0% 80.1% 36.4% inter: 3.9% 7.0% 0.7%
[libx264 @ 0x55963ad4b700] i16 v,h,dc,p:  2% 74%  6% 18%
[libx264 @ 0x55963ad4b700] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 13% 36% 20%  8%  4%  2%  6%  4%  8%
[libx264 @ 0x55963ad4b700] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 20% 41% 10%  4%  7%  4%  5%  3%  5%
[libx264 @ 0x55963ad4b700] i8c dc,h,v,p: 44% 37% 14%  6%
[libx264 @ 0x55963ad4b700] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x55963ad4b700] kb/s:1364.00


  


  So it is basically dropping 887 frames. The output file has the full audio but no video.
Is this even possible ?