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• avcodec/mpeg4videodec : Clear bits_per_raw_sample if it has originated from a previous...

  9 juin 2018, par Michael Niedermayer

  avcodec/mpeg4videodec : Clear bits_per_raw_sample if it has originated from a previous instance
  Fixes : assertion failure
  
  Fixes : ffmpeg_crash_5.avi
  Found-by : Thuan Pham <thuanpv@comp.nus.edu.sg>, Marcel Böhme, Andrew Santosa and Alexandru Razvan Caciulescu with AFLSmart
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mpeg4videodec.c

• ffmpeg fast seek not working for MP4 over HTTP

  27 juillet 2024, par Gmanicus

  I'm attempting to download snapshots from a video provided by the U.S House of Representatives :

  


  https://houseliveprod-f9h4cpb9dyb8gegg.a01.azurefd.net/east/2024-04-11T08-55-12_Download/video_3000000_1.mp4


  


  I am using fluent-ffmpeg in Node to execute this command :

  


  ffmpeg('https://houseliveprod-f9h4cpb9dyb8gegg.a01.azurefd.net/east/2024-04-11T08-55-12_Download/video_3000000_1.mp4')
  .inputOption(`-ss 03:33:33`)
  .outputOptions([
     '-vframes 1'
  ])
  .output('test.png')

// Effectively:
// ffmpeg -ss 03:33:33 -i  -y -vframes 1 test.png


  


  My intention is to fast-seek to the desired timestamp and take a snapshot over HTTP. However, when doing so, the performance is not great. A snapshot takes about 10s per 3hrs of video and seems to increase fairly linearly at that rate.

  


  However, when using ffmpeg on the same video locally, it's super fast ! Sub-500ms regardless of the desired timestamp.

  


  Is there some magic that could be done via ffmpeg options or perhaps some sort of technique with manual requests to get a snapshot at the desired segment of video more efficiently ?

  


• ffmpeg merge_outputs not outputting the final file

  30 mai 2020, par Ethanopp

  I am trying to combine multiple independent instrument audio tracks (.ogg files) from a song into 1 final 'song' file that has them all playing simultaneously.

  



  The following properly outputs each independent .mp4 file, but once it's done running, I don't see a final file with everything combined...

  



  import ffmpeg
import os

os.environ['path'] = 'C:\\Program Files (x86)\\ffmpeg\\bin'

song = ffmpeg.input('song.ogg').output('song.mp4').audio
drums = ffmpeg.input('drums_1.ogg').output('drums1.mp4').audio
drums2 = ffmpeg.input('drums_2.ogg').output('drums2.mp4').audio
drums3 = ffmpeg.input('drums_3.ogg').output('drums3.mp4').audio
guitar = ffmpeg.input('guitar.ogg').output('guitar.mp4').audio
vocals = ffmpeg.input('vocals.ogg').output('vocals.mp4').audio
rhythm = ffmpeg.input('rhythm.ogg').output('rhythm.mp4').audio

out = ffmpeg.merge_outputs(song, drums, drums2, drums3, guitar, vocals, rhythm)

ffmpeg.run(out)