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• FFmpeg - How can I stop recording after the stream (m3u8) over ?

  30 juin 2022, par Erle

  How do I stop record stream m3u8 after the stream over ? My point of this question was avoiding from corrupted files, my current command is working fine I tried to CRTL + C to the Command Prompt (to stop the command) and it sometimes doesn't corrupted and sometimes it got corrupted

  


  ffmpeg -loglevel "quiet" -i "my-stream.m3u8" -filter_complex scale=1280:720 -map 0:a -c:a copy -bsf:a aac_adtstoasc "Output.mp4"


  


• ffv1dec : Avoid unnecessarily large stack usage and copies.

  2 septembre 2014, par Reimar Döffinger

  ffv1dec : Avoid unnecessarily large stack usage and copies.
  Ideally the compiler could figure this out on its own,
  
  but it seems it can’t.
  
  An alternative that would avoid the messy explicit memcpy
  
  would be to use a sub-struct for the parts that should
  
  be preserved, which can then simply be assigned.
  Signed-off-by : Reimar Döffinger <Reimar.Doeffinger@gmx.de>
  

  • [DH] libavcodec/ffv1dec.c

• FFMPEG converting HEVC to VP9 large file size

  27 mai 2019, par Tom B

  I’m trying to convert HEVC videos to VP9 so they can be played in a web browser while keeping file size roughly the same.

  I am struggling to create a video with similar quality/file size.

  Here’s the stream info for one of the HEVC videos the video is is 22:49 and 168.7mb :

  Stream #0:0(und): Video: hevc (Main) (hev1 / 0x31766568), yuv420p(tv, bt709), 1920x1080, 900 kb/s, 23.98 fps, 23.98 tbr, 90k tbn, 23.98 tbc (default)

  The bitrate is 900K so I had thought that the following command would use the same bitrate and give a roughly similar image quality :

  ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -vaapi_device /dev/dri/renderD128 -i "$infile" -vf 'format=nv12,hwupload' -c:v vp9_vaapi -b:v 900K -bf 2 -bsf:v vp9_raw_reorder,vp9_superframe -c:a libvorbis "$outfile"

  Using this, the quality is noticeably much, much worse and busy scenes look incredibly blocky though the file size is roughly equivalent to the HEVC source.

  If I omit the bitrate and let VP9 work it out

  ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -vaapi_device /dev/dri/renderD128 -i "$infile" -vf 'format=nv12,hwupload' -c:v vp9_vaapi -b:v 0 -bf 2 -bsf:v vp9_raw_reorder,vp9_superframe -c:a libvorbis "$outfile"

  The quality is visually indistinguishable but the file size of the VP9 converted video reaches 401mb, up from 168mb of the HEVC file and during encoding the bitrate is over 3m for most of the video.

  I tried going up to 1.2M (33% higher than the source video) and VP9 still gave a very blocky looking video.

  Is VP9 really that much worse than HEVC or is there an option I am missing ? or is it because I am converting from HEVC ?