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• ffmpeg : is vidstab multithreaded, and/or is there a way to make it perform better on a very high # of cores ?

  30 juillet 2016, par ljwobker

  I’m working on a project where I use the vidstab ffmpeg plugin to stabilize some videos. I’m lucky enough to have access to an extremely fast x86 machine (2 socket, 16 core, 32 thread) but I can’t seem to keep it busy and I’m trying to figure out if it’s a limitation of the toolchain or the config/commands. The workflow is basically 3 steps :

  1. crop the video in terms of both time and dimension (ffmpeg "crop"
     filter)
  2. run vidstabdetect to identify the transformation corrections
  3. run vidstabtransform to apply the transformation and output the
     final video

  When I run the transcode script on this machine, the "crop" pass executes extremely fast, and the htop output from the machine clearly shows all 32 cores(threads) running at nearly 100%.

  When I run the pass with vidstabdetect, htop clearly shows one core running at/near 100%, with all of the other cores hovering in the "few percent" range, and total CPU utilization for the parent PID hovers near 130%. This leads me to believe there must be only one main processing thread, but also several other smaller threads that are consuming at least some parallel time.

  the vidstabtransform pass looks similar, with one core constantly near 100%, and the rest of the cores hovering in the few percent.

  As far as I can tell, there is no way to parallelize the two vidstab processes, as the transform step is completely dependent on the results of the detection pass. There is a single pass option described in the vidstab docs, but the quality isn’t as good so I’m trying to avoid that.

• Android : FFmpeg taking high memory/cpu usage causing crash

  29 janvier 2019, par dastan

  I compiled ffmpeg for android, enabled mediacodec and jni. its works but when I merge HD video 60fps, its crash the app. this ffmpeg cmd I am using.

  [-y, -benchmark, -ss, 0.0, -t, 11.541, -i, VID_HD.mp4, -filter_complex, [0:v]setpts=PTS-STARTPTS,scale=1080.0:1920.0:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2:color=#000000, -c:v, libx264, -c:a, aac, -ac, 2, -ar, 44100, -preset, ultrafast, -strict, -2, VID_HD.ts]

  Sometimes I get these error for same cmds, but when I rerun, it works and sometimes these, if I rerun 3-4 times its restart the app. maybe because of memory is not cleaning. Help me here.

  Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
  
  
  
  VideoKit:Error: Failed to inject frame into filter network: Out of memory
  
  
  
  VideoKit:Error: Error while processing the decoded data for stream #0:0

  I need help in cleaning FFmpeg also when execution finished and I call my run(FFmpeg cmds) method for next video encoding it restart the app, I am suspecting because of memory usage.

• Update .m3u8 playlist while live streaming

  28 juillet 2022, par Juan Trejos

  Im using nginx-rtmp-module to create a RTMP server and I'm using hls directives to create the playlist.

  


  hls on;
hls_path /var/www/html/cam/;
hls_fragment 10;
hls_nested on;
hls_playlist_length 7d;
hls_cleanup off;
hls_continuous on;
hls_fragment_naming system;


  


  Now, I want to update manually the .m3u8 playlist file from this :

  


  #EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-TARGETDURATION:12
#EXTINF:10.000,
1658833177814.ts
#EXTINF:10.000,
1658833187826.ts
#EXTINF:10.000,
1658833197826.ts


  


  to this, when the streaming is "on line" :

  


  #EXTM3U
#EXT-X-VERSION:3  
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-TARGETDURATION:12
#EXTINF:10.000,
1658833197826.ts


  


  if I do it when there is no live streaming, that works, but if i do it when there is a live streaming, the .m3u8 file becames as the original after the server finish the creation of the last chunk. Even if i delete the .m3u8 file, it is recreated as the original one.

  


  I've also tryed it using ffmpeg instead of hls directives without success, and looked this solution but 😥😥