Recherche avancée

Sur d’autres sites (8738)

• Performant AV1 encoding, does it exist ?

  29 novembre 2022, par V O

  I'm developing a VoD application as a white label product that runs in a SaaS context using K8s. To enable streaming, I take the input video and re-convert it into HLS segments in multiple version and codecs to reach maximum compatibility.

  


  Yesterday I started implementing AV1 as codec, as it will in near future detach h264 as it's more efficient with the same level of compatibility across all the available browsers.
That was the point where things started to get strange, as I want to have this codec instead of h264 ^^.

  


  If you take a look at the following doc pages from ffmpeg : https://trac.ffmpeg.org/wiki/Encode/AV1

  


  You will notice that there are 3 main encoders available to handle encoding to av1. These are : libaom, SVT-AV1 and rav1e. No matter which one of these I try, the performance is slow, even slower than with HEVC. Recently I came along a news article about Netflix and that they are upgrading their library to AV1. If I take a look at the numbers of media elements Netflix offers, the amount is just huge, and I really don't understand how they did it. From what I know, SVT-AV1 is developed by Netflix in cooperation with Intel, So I assume they somehow rely on hardware encoding using an Intel CPU extension.

  


  Does somebody maybe know more and how they did it ? I really can't imagine that they just do CPU only encoding. A movie would take days to get encoded.

  


  Thanks in advance

  


• C api on capturing video stream from webcam using ffmpeg

  14 juillet 2013, par Tanjim Hossain Sifat

  I am a new user of ffmpeg. Ffmpeg has a good documentation on using it in command-line, but i am looking for some C API code.

  I want to make a software using C, that would capture video stream from webcam and give me the video stream in raw format, that I would encode in a codec later.

  I have visited this given link, but it provided only the command-line use, not the use of libraries provided by ffmpeg :
  http://ffmpeg.org/trac/ffmpeg/wiki/How%20to%20capture%20a%20webcam%20input

  I also visited this link, which gave me good idea on using the libavcodec, but no other tutorial is available :
  ffmpeg C API documentation/tutorial

  Please someone help me finding C api on video stream capturing from webcam using ffmpeg's library. Thanks in advance.

• Unrecognized options even though compiled FFmpeg on Ubuntu manually

  11 février 2016, par Kathy Lee

  I would like to convert a video from .avi to .mp4 with same quality using ffmpeg but the command I put in the terminal always report some errors saying that there are unrecognized options.

  I have compiled the ffmpeg manually following the steps in http://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

  After compiling the ffmpeg, I used the command below the compress the video

  ffmpeg -i input.avi -c:v libx264 -crf 19 -preset slow -c:a libfaac -b:a 192k -ac 2 output.mp4

  But the error message is saying "Unrecognized option ’crf’" :

  ffmpeg version 2.8.5 Copyright (c) 2000-2016 the FFmpeg developers
  
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04)
  
  configuration: --enable-nonfree --enable-pic --enable-shared
  
  libavutil      54. 31.100 / 54. 31.100
  
  libavcodec     56. 60.100 / 56. 60.100
  
  libavformat    56. 40.101 / 56. 40.101
  
  libavdevice    56.  4.100 / 56.  4.100
  
  libavfilter     5. 40.101 /  5. 40.101
  
  libswscale      3.  1.101 /  3.  1.101
  
  libswresample   1.  2.101 /  1.  2.101
  
  Unrecognized option 'crf'.
  
  Error splitting the argument list: Option not found

  Then I tried to omit flag -crf, but I got error saying

  Unrecognized option 'preset'.
  
  Error splitting the argument list: Option not found

  Then I omitted flag -preset, it says I do not have libx264....

  [mjpeg @ 0x164f2c0] Changeing bps to 8
  
  Input #0, avi, from 'backup_bush.avi':
  
    Duration: 00:01:40.70, start: 0.000000, bitrate: 12409 kb/s
  
      Stream #0:0: Video: mjpeg (MJPG / 0x47504A4D), yuvj420p(pc, bt470bg/unknown/unknown), 400x250 [SAR 1:1 DAR 8:5], 12407 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
  
  Unknown encoder 'libx264'

  I am very confused what is going on because I have complied ffmpeg step by step and also installed the dependencies such as libx264 as described in http://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu. The command I used to configure ffmpeg is

   ./configure   --prefix="$HOME/ffmpeg_build"   --pkg-config-flags="--static"   --extra-cflags="-I$HOME/ffmpeg_build/include"   --extra-ldflags="-L$HOME/ffmpeg_build/lib"   --bindir="$HOME/bin"   --enable-gpl   --enable-libass   --enable-libfdk-aac   --enable-libfreetype   --enable-libmp3lame   --enable-libopus   --enable-libtheora   --enable-libvorbis   --enable-libvpx   --enable-libx264   --enable-nonfree

  Why these errors happen ? How can I fix them to allow me to convert the video from .avi to .mp4 ?

  Thank you very much !