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• Best way to convert video from h264 to h265 and copy audio without lose too match quality

  9 mai 2021, par user3449922

  I have some mkv file ripped from blu ray and I like to convert it to h265 with ffmpeg.

  


  I have tried this command :

  


  ffmpeg.exe -i title00.mkv -c:v hevc_nvenc test_2.mkv


  


  and the result seem incredible : original size : 27 GB , output size : 1.6 GB

  


  Francanly I don't expect a similar result that is very strange.

  


  The quality seem similar at the fist look, but I don't belive it.

  


  I ask if there is a better way to preserve the original quality and it is not important if the output size is 4 or 5 GB that is in all cases a excellet result.

  


  I have Nvidia GTX 1060 6GB

  


  Can you suggest me a best way to do it ?

  


• ffmpeg_videotoolbox : skip memory copy if hwaccel_output_format match

  27 avril 2021, par zhilizhao

  ffmpeg_videotoolbox : skip memory copy if hwaccel_output_format match
  Simple test results :
  Command :
  
  ./ffmpeg -y -hwaccel videotoolbox -hwaccel_output_format videotoolbox_vld \
  
    -i test.mp4 -an -c:v h264_videotoolbox -benchmark out.mp4
  Before :
  
  frame= 1221 fps= 66 q=-0.0 Lsize=    3144kB time=00:00:20.33 bitrate=1266.6kbits/s dup=4 drop=0 speed= 1.1x
  
  bench : utime=2.714s stime=1.218s rtime=18.574s
  After :
  
  frame= 1221 fps=137 q=-0.0 Lsize=    3144kB time=00:00:20.33 bitrate=1266.4kbits/s dup=4 drop=0 speed=2.28x
  
  bench : utime=1.450s stime=1.440s rtime=8.924s
  It has limited usecase since there is no video filter support, so
  
  a log message is added to notify the user.
  Reviewed-by : Steven Liu <liuqi05@kuaishou.com>
  

  • [DH] fftools/ffmpeg_videotoolbox.c

• Why Video and Audio Don't Match ?

  19 août 2021, par Ohpy

  there is an ffmpeg code.

  


  fmpeg -i "1.mp4" -vf "zoompan=z='if(lte(mod(time,4.99),2.03),4,0)':d=1:x=iw/2-(iw/zoom/2):y=ih/2-(ih/zoom/2):fps=23.98" -af "firequalizer=gain_entry='entry(0,-23);entry(250,-1100.5);entry(1000,0);entry(4000,1);entry(16000,16)'" -metadata title="" -metadata artist="" -metadata album_artist="" -metadata album="" -metadata date="" -metadata track="" -metadata genre="" -metadata publisher="" -metadata encoded_by="" -metadata copyright="" -metadata composer="" -metadata performer="" -metadata TIT1="" -metadata TIT3="" -metadata disc="" -metadata TKEY="" -metadata TBPM="" -metadata language="eng" -metadata encoder="" -threads 0 -preset superfast 1OUT.mp4


  


  This code zooms in and out of the image in the video. It also changes the sound frequency.

  


  When the process of the video is finished, the image in the video and the sound do not match.

  


  For example, the sound that should be at the 10th second of the video is at the 15th second. How can I prevent this ?

  


  Can you help me ?