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• Wildcard for sequential images

  16 septembre 2013, par abalter

  I'm trying to animate a series of jpg files using avconv. Based on numerous examples, I'm trying using %d.jpg to specify the files. Or %05d.jpg. However, I'm getting :

  avconv -i %d.jpg a.avi
  
  avconv version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the Libav developers built on Jun 12 2012 16:37:58 with gcc 4.6.3
  
  %d.jpg: No such file or directory

  Here is a snip of my directory listing :

  10380.jpg
  
  10390.jpg
  
  10400.jpg
  
  1040.jpg
  
  10410.jpg
  
  10420.jpg
  
  10430.jpg
  
  10440.jpg

  There are jpegs from 00000.jpg to 14400.jpg

  I don't really understand that wildcard system, but that is what is in examples.

  (note : I tagged it ffmpeg because a tag for avconv does not exist, and avconv supersedes ffmpeg)

  Update
  I'm updating the question based on the answer below by @av501.

  To begin with, I have a list of png files with sequential ordering by 10. They have text preceding a 5 digit integer. For example :

  SkinMattekNutrient_py_00000.png
  
  SkinMattekNutrient_py_00010.png
  
  SkinMattekNutrient_py_00020.png
  
  ...
  
  SkinMattekNutrient_py_10440.png

  What would be the way to batch convert these to jpg ? I tried

  convert ...
  
  SkinMattekNutrient_py_%05d.png %05d.jpg

  and

  convert ...
  
  SkinMattekNutrient_py_%5d.png %5d.jpg

  But I get :

  convert SkinMattekNutrient_py_%05d.png %05d.jpg
  
  convert: missing an image filename `%05d.jpg' @ error/convert.c/ConvertImageCommand/3011.

• How can I encode a real-time video from dynamically spaced frames ?

  7 mai 2019, par Ujuf66

  I’m trying to create a video from a series of screenshots. The screenshots are in a database and have dynamic FPS (1-3 FPS). How can I create a video file with constant FPS ?

  Before performing av_packet_rescale_ts I tried to change the st^.codec.time_base.den value on the fly between 1 and 3.

  This is the basic cycle of encoding of one picture :

  repeat
  
    fillchar(pkt, sizeof(TAVPacket), #0);
  
    av_init_packet(@pkt);
  
  
  
    (* encode the image *)
  
    ret := avcodec_encode_video2(st^.codec, @pkt, frame, got_packet);
  
    if (ret < 0) then
  
    begin
  
      writeln(format('Error encoding video frame: %s', [av_err2str(ret)]));
  
      exit;
  
    end;
  
  
  
    if (got_packet > 0) then
  
    begin
  
      (* rescale output packet timestamp values from codec to stream timebase *)
  
      av_packet_rescale_ts(@pkt, st^.codec.time_base, st^.time_base);
  
      pkt.stream_index := st^.index;
  
  
  
      log_packet(oc, @pkt);
  
      (* Write the compressed frame to the media file. *)
  
      av_interleaved_write_frame(oc, @pkt);
  
    end;
  
    inc(frame.pts);
  
  
  
  until (av_compare_ts(frame.pts, st^.codec^.time_base, 1, av_make_q(1, 1)) >= 0);

  Changing the FPS on the fly causes the video output to fail. If I don’t change the st^.codec.time_base.den value the video speeds up and slows down.

• lavfi/vf_libplacebo : support blending multiple inputs

  15 juin 2023, par Niklas Haas

  lavfi/vf_libplacebo : support blending multiple inputs
  Subsequent inputs require frame blending to be enabled, in order to not
  
  overwrite the existing frame contents.
  For output metadata, we implicitly copy the metadata of the *first*
  
  available stream (falling back to the second stream if the first has
  
  already reached EOF, and so on). This is done to resolve any conflicts
  
  between inputs with differing metadata. So when e.g. input 1 is HDR and
  
  output 2 is SDR, the output will be HDR, and vice versa. This logic
  
  could probablly be improved by dynamically determining some "superior"
  
  set of metadata, but I don't want to handle that complexity in this
  
  series.
  

  • [DH] libavfilter/vf_libplacebo.c