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• avcodec/mpeg4videodec : Remove always-true checks

  12 octobre 2022, par Andreas Rheinhardt

  avcodec/mpeg4videodec : Remove always-true checks
  codec_id is always AV_CODEC_ID_MPEG4 for mpeg4_decode_mb(),
  
  as the MPEG-4 decoder is the only decoder for which
  
  ff_mpeg4_decode_picture_header() as well as decode_init()
  
  are ever called and these are the only places where
  
  the decode_mb function pointer is ever set to mpeg4_decode_mb().
  
  ff_mpeg4_workaround_bugs() is also only called for the MPEG-4
  
  decoder (the caller checks the codec id).
  (ff_mpeg4_decode_picture_header() is also called for the MPEG-4
  
  parser, but it never uses the decode_mb function pointer.)
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/mpeg4videodec.c

• FFmpeg reverse long audio hang randomly in Android

  23 mars 2021, par Michael

  I am writing an Android APP, underneath I simply use FFmpeg command to reverse the audio.

  


  The command is simple like :ffmpeg -loglevel debug -debug_ts -i /sdcard/.m4a -af areverse /sdcard/longaudio.aac

  


  If the audio is short, everything works fine, but if the audio longer than 10 mins, the thread will hang(sleep) randomly at some places. The log shows input processing stop in middle at some pkt_pts, every time stop at different ptk_pts. The whole app will therefore hang in there.

  


  If I simply do conversion "ffmpeg -loglevel debug -debug_ts -i /sdcard/.m4a -codec:a aac /sdcard/longaudio.aac" it will work.

  


  Some debug steps I did :

  


  


  1. The memory and cpu usage is normal, it seems the ffmpeg just suddenly decide to take a rest during reverse the long audio :(

     


  


  2. the IO shouldn't be fulled, I commented out the logs still not ok.

     


  


  3. I see a lot "cur_dts is invalid (this is harmless if it occurs once at the start per stream)", but it also showed in normal cases.

     


  


  


  I know the description is kind of ambiguous, but I am so desperate. Anything I don't know about the audio reverse is welcome.

  


• ffmpeg "ignore_loop 0" seems not work on specific gif

  16 mars 2023, par Peter.k

  I use code which worked for every gif I used to embed it within a video :

  


  ffmpeg -i e:\tt121b+.mp4 -ignore_loop 0 -i e:\gals\1\gif.gif -filter_complex "[1:v][0:v]scale2ref=oh*mdar:ih/10[ua][b];[ua]setsar=1,format=yuva420p,colorchannelmixer=aa=0.5[u];[b][u]overlay=(main_w-w)-(main_w*0.1):(main_h-h)-(main_h*0.125):shortest=1" -r 25 -b:v 1500k e:/tt121_logo.mp4


  


  It literally adds an animated image to video on specified place and with chosen size. But when I add a gif which has 180 frames it behaves weirdly. After 15 seconds the gif is looped one, then it stops and the whole video stops but program still codes it to the end but with higher speed. Additionally, the ram is used to the maximum after this breakdown.

  


  What's going on there ? Should I put some additional parameters ? I tried to add -loop 0, -loop 1 in different places and also removed shortest=1 parameter but its either does nothing or the gif have 1 loop and stops.

  


  EDIT

  


  Found the problem. I opened this gif in first found editor and saw that it was not saved as looped infinitely. Saved it in that format and it works. Didn't know the ffmpeg -loop parameters don't make it. However, this unlooped gif worked as looped in preview software to add more mess to the topic.