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• fate : add chroma position scale test

  23 septembre 2015, par Christophe Gisquet

  fate : add chroma position scale test
  The sample position is made weird and non-nominal to force catching
  
  such issues as default values or specialized operations hiding
  
  issues in corner cases.
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] tests/fate/filter-video.mak
  • [DH] tests/ref/fate/filter-scalechroma

• Use ffmpeg as external tool to stream 2 or more different sources via pipeline

  25 février 2021, par StackDOX

  I have an application running on an embedded system. This application has 2 video sources (and, theorically, 1 audio source). Concentrating to the video sources, I have 2 subprocess that computes different frames sets (unrelated each others). I want to send these frames to 2 differents streams.

  


  I would to avoid to write a lot of ffmpeg/libav code. I have ffmpeg compiled for the embeeded system and I can use it as tool. For example, I can write to the stdout the first frames set and pass it to the ffmpeg like this :

  


  ./my_app|ffmpeg -an -i - -vcodec copy -f rtp rtp://"remote_ip

  


  This basically works. But, now i would to send the other one frame set. How to do that ? Theorically I need anoter ffmpeg instance that read from another source that can't be the stdout of "my_app", because is already busy.

  


  ---

  


  I'm thinking to use 2 video files as support. I can record the 2 frames sets into 2 video files and then run 2 ffmpeg instances from these sources. In this case I think I need a way to limit the video files dimensions (like a circular buffer), because 2 streams can become really huge in time. It is a possibility ?
This can sound "weird" to me : I need to record a video source in realtime and stream it via ffmpeg (always in realtime). I don't know if it is a good idea, there are realtime problems for sure :

  


  loop:
my_app --write_into--> video_stream1.mp4 
ffmpeg <--read_from-- video_stream1.mp4

my_app --write_into--> video_stream2.mp4 
ffmpeg <--read_from-- video_stream2.mp4


  


  Have you some suggestion to address this kind of situation ?

  


  many thanks, bye.

  


• ffmpeg complex_filter fadeout not working

  11 avril 2015, par Macmee

  Essensially what I am trying to do is concat a.mp4 with b.mp4, display my set of %c.png overlayed ontop for the entire duration of the video and also show d.png overlayed ontop but only for 1 second and then have it fade out. ALL of this works except that d.png remains overlayed and never fades out :

  ffmpeg -i ./temp/a.mp4 -i media/b.mp4 -i media/splash/%c.png -i ./temp/d.png -y -filter_complex [0:v]scale=568x320,setpts=PTS-STARTPTS[v0];[1:v]scale=568x320,setpts=PTS-STARTPTS[v1];[2:v]scale=212:242,setpts=PTS-STARTPTS[v2];[3:v]trim=duration=0.5,fade=t=out:st=0:d=0.5[3:v];[v0][0:a][v1][1:a]concat=n=2:v=1:a=1[bg][a];[bg][v2]overlay=(W-w)/2:(H-h)/2,format=yuv420p[v];[v][3:v]overlay=(W-w)/2:(H-h)/2,format=yuv420p[v] -map [v] -map [a] -r 29.97 -vcodec libx264 -s 568x320 -flags +loop -b 400k -bufsize 4M -bt 256k -refs 1 -coder 0 -me_range 16 -subq 4 -partitions +parti4x4+parti8x8+partp8x8 -g 250 -keyint_min 25 -level 30 -qmin 10 -qmax 51 -qcomp 0.6 -trellis 2 -sc_threshold 40 -i_qfactor 0.71 -acodec aac -strict experimental -ab 80k -ar 48000 -ac 2 -strict experimental -f mp4 -metadata:s:v:0 rotate=90 ./temp/1428723401371.mp4

  Lord Neckbeard, I know you’re out there. I’ve been reading your stackoverflow posts on fade in/out with complex_filter for a few hours now and nothing I’ve tried has succeeded. Please Lord, accept the above as my humble offering to you and help me fadeout d.png after 1 second.