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• ffmpeg - Encoding Percentage Maths

  12 juillet 2012, par Jimbo

  I've written a whole system in PHP and bash on the server to convert and stream videos in HTML5 on my VPS. The conversion is done by ffmpeg in the background and the contents is output to block.txt.

  Having looked at the following posts :

  Can ffmpeg show a progress bar ?

  and

  ffmpeg video encoding progress bar

  amongst others, I can't find a working example.

  I have always struggled with the regexes and maths, and I need to grab the currently encoded progress as a percentage.

  The first post I linked above gives :

  $log = @file_get_contents('block.txt');
  
  
  
  preg_match("/Duration:([^,]+)/", $log, $matches);
  
  list($hours,$minutes,$seconds,$mili) = split(":",$matches[1]);
  
  $seconds = (($hours * 3600) + ($minutes * 60) + $seconds);
  
  $seconds = round($seconds);
  
  
  
  $page = join("",file("$txt"));
  
  $kw = explode("time=", $page);
  
  $last = array_pop($kw);
  
  $values = explode(' ', $last);
  
  $curTime = round($values[0]);
  
  $percent_extracted = round((($curTime * 100)/($seconds)));
  
  
  
  echo $percent_extracted;

  The $percent_extracted variable echoes zero, and as maths is not my strong point, I really don't know how to progress here.

  Here's one line from the ffmpeg output from block.txt (if it's helpful)

  time=00:19:25.16 bitrate= 823.0kbits/s frame=27963 fps= 7 q=0.0 size=
  117085kB time=00:19:25.33 bitrate= 823.1kbits/s frame=27967 fps= 7
  q=0.0 size= 117085kB time=00:19:25.49 bitrate= 823.0kbits/s
  frame=27971 fps= 7 q=0.0 size= 117126kB

  Please help me output this percentage, once done I can create my own progress bar. Thanks.

• What are good settings for transcoding videos uploaded to my app ?

  14 mai 2020, par Dmitry Minkovsky

  I am working on an app that allows users to share videos. The problem is that many videos are very high bitrate. For example, A 4-minute H264 video from an old iPhone is encoded at 1080p and runs 17,000 kb/s ( 500 megabytes). Accepting and distributing such videos at this bitrate/resolution is not practical for a social application.

  



  I have been playing with ffmpeg to transcode videos to smaller sizes and higher compression, but have not achieved acceptable results. For example :

  



  ffmpeg \
    -i in.mov \
    -vf scale=w='if(gt(iw\,ih)\,780\,-2)':h='if(gt(iw\,ih)\,-2\,780)' \ 
    -c:v libx264 \
    -crf 28 \
    -preset medium \
    -pix_fmt yuv420p \
    -movflags +faststart \
    out.mp4


  



  This command transcodes the above-mentioned 500MB file down to 70MB. It scales the larger dimension of the video to 780 pixels and compresses the video quite a bit. The results are okay, but the file is still large.

  



  Taking the longer dimension down to 480 pixels, the file is reduced to 40MB. Still quite large, and now significantly degraded. Also, the transcoding still takes quite a long time : about 1-1.5x on my 4 year old i7 Macbook Pro with 16GB RAM.

  



  I'm not sure how to improve on this. H265 is not supported in browsers. I am wondering :

  



  

  • How can I reduce size further ?

  


  • How can I transcode faster than 1x without significantly reducing quality ? Even 2-3x doesn't seem great ?

  


  



  Is this as good as it gets ?

  


• lavfi/drawutils : improve colorspace support

  2 juin 2022, par rcombs

  lavfi/drawutils : improve colorspace support
   Introduce ff_draw_init2, which takes explicit colorspace and range
  
    args
  
   Use lavu/csp and lavfi/colorspace for conversion, rather than the
  
    lavu/colorspace.h macros
  
   Use the passed-in colorspace when performing RGB->YUV conversions
  The upshot of this is :
  
   Support for YUV spaces other than BT601
  
   Better rounding for all conversions
  
   Particular rounding improvements in >8-bit formats, which previously
  
    used simple left-shifts
  
   Support for limited-range RGB
  
   Support for full-range YUV in non-J pixfmts
  Due to the rounding improvements, this results in a large number of
  
  minor changes to FATE tests.
  Signed-off-by : rcombs <rcombs@rcombs.me>
  

  • [DH] libavfilter/drawutils.c
  • [DH] libavfilter/drawutils.h
  • [DH] tests/ref/fate/filter-chromashift-smear
  • [DH] tests/ref/fate/filter-chromashift-wrap
  • [DH] tests/ref/fate/filter-decimate
  • [DH] tests/ref/fate/filter-fps-down
  • [DH] tests/ref/fate/filter-fps-down-eof-pass
  • [DH] tests/ref/fate/filter-fps-down-round-down
  • [DH] tests/ref/fate/filter-fps-down-round-up
  • [DH] tests/ref/fate/filter-fps-start-drop
  • [DH] tests/ref/fate/filter-fps-start-fill
  • [DH] tests/ref/fate/filter-fps-up
  • [DH] tests/ref/fate/filter-fps-up-round-down
  • [DH] tests/ref/fate/filter-fps-up-round-up
  • [DH] tests/ref/fate/filter-framerate-12bit-down
  • [DH] tests/ref/fate/filter-framerate-12bit-up
  • [DH] tests/ref/fate/filter-framerate-down
  • [DH] tests/ref/fate/filter-framerate-up
  • [DH] tests/ref/fate/filter-metadata-signalstats-yuv420p10
  • [DH] tests/ref/fate/filter-minterpolate-down
  • [DH] tests/ref/fate/filter-minterpolate-up
  • [DH] tests/ref/fate/filter-mpdecimate
  • [DH] tests/ref/fate/filter-overlay_yuv420p10
  • [DH] tests/ref/fate/filter-overlay_yuv422p10
  • [DH] tests/ref/fate/filter-pixfmts-pad
  • [DH] tests/ref/fate/filter-pixfmts-tinterlace_pad
  • [DH] tests/ref/fate/filter-testsrc2-yuv420p
  • [DH] tests/ref/fate/filter-testsrc2-yuv444p
  • [DH] tests/ref/fate/filter-tpad-add
  • [DH] tests/ref/fate/filter-tpad-clone
  • [DH] tests/ref/fate/filter-unsharp-yuv420p10
  • [DH] tests/ref/fate/filter-untile