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• How to convert VP8 track with different frame resolution to h264

  13 septembre 2016, par Nikita

  I have a .webm file with VP8 track, recorded from WebRTC stream by external service (TokBox Archiving). The stream is adaptive, so each frame in track could have different resolution. Most players (in webkit browsers) use video resolution from track description (which is always 640x480) and scale frames to this resolution. Firefox and VLC player uses real frame resolution, changing video resolution respectively.

  I want to achieve 2 goals :

  1. play this video in Internet Explorer 9+ without additional plugin installation.
  2. change frames resolution to one fixed resolution, so the video will look identically in different browsers.

  So, my plan is :

  • extract frames from source webm file to images with real frame resolution (e.g. PNG or BMP) (how could I do that ?)
  • find max width and max height of images
  • add black padding to images, so smaller frames will be in the center of a new frame (of size MAX_WIDHTxMAX_HEIGHT)
  • combine images to h264 track using ffmpeg

  Is all correct ? How can I achieve this ? Can this algorithm be optimized some way ?

  I tried ffmpeg to extract images, but it does not parse real frame resolution, using resolution from track header.
  I think some libwebm functions can help me (to parse frame headers and extract images). Maybe someone has some code snippets to do this ?

  Example .webm (download source, do not play google-converted version) : https://drive.google.com/file/d/0BwFZRvYNn9CKcndhMzlVa0psX00/view?usp=sharing

  Official description of adaptive stream from TokBox support : https://support.tokbox.com/hc/en-us/community/posts/206241666-Archived-video-resolution-is-supposed-to-be-720x1280-but-reports-as-640x480

• libavcodec/amfenc : Vulkan initialization support for encoder.

  8 août 2019, par OvchinnikovDmitrii

  libavcodec/amfenc : Vulkan initialization support for encoder.
  Added linux support for amf encoder through vulkan.
  To use h.264(AMD VCE) encoder on linux amdgru-pro version 19.20+ and
  
  amf-amdgpu-pro package(amdgru-pro contains, but does not install
  
  automatically) are required.
  This driver can be installed using amdgpu-pro-install script in
  
  official amd driver archive.
  Initialization of amf encoder occurs in this order :
  
  1) trying to initialize through dx11(only windows)
  
  2) trying to initialize through dx9(only windows)
  
  3) trying to initialize through vulkan
  Only Vulkan initialization available on linux.
  

  • [DH] Changelog
  • [DH] doc/general.texi
  • [DH] libavcodec/amfenc.c
  • [DH] libavcodec/version.h

• Why does mplayer not play my stream ?

  17 juillet 2016, par SirWindfield

  I wanted to use mplayer (a command line tool) to play a SoundCloud url that I fetched with there official API. The url looks like this

  https://cf-media.sndcdn.com/qop35iYKlHhs.128.mp3?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiKjovL2NmLW1lZGlhLnNuZGNkbi5jb20vcW9wMzVpWUtsSGhzLjEyOC5tcDMiLCJDb25kaXRpb24iOnsiRGF0ZUxlc3NUaGFuIjp7IkFXUzpFcG9jaFRpbWUiOjE0Njg3NTM4NjB9fX1dfQ__&Signature=OZ4IawmjdU6hEN8KB8e~t3QTy4lBFVBbIDg-a6tuPkb65e0mPskkCFFASkTWbyy5lsaT9IrURan6y70sZhLXPbng1IfkTsGdX1dO938NwVYnKs-BS7IL4TiVFxTBXoKJgmCmUD0qmmGmYqm3YdGZQrP~Sj~mw9~fmtwdHQu0rhl3O-dKsgk497JAR6pMorQs7BSs0XIosV1Mmv2DMD6iifquCWV9Ezq4ekneQ1gfSjVmzjjnKvsxjPpgmU~5DTdewwzlNClVxdzHSQONWM7c0YMGlBcVz97NviaeZOQSCAW8QZS59WULXJBJ9OmEPctWtpe3O0mo-GYjwEkbVGYl9A__&Key-Pair-Id=APKAJAGZ7VMH2PFPW6UQ

  I use the command "mplayer ’url’" to play it but I always get the output :

  libavformat version 57.25.100 (internal)
  
  https protocol not found, recompile FFmpeg with openssl, gnutls,
  
  or securetransport enabled.

  Looking which protocols have been installed tells me that I have https input and output support (ffmpeg -protocols) :

  ffmpeg version 3.1.1 Copyright (c) 2000-2016 the FFmpeg developers
  
    built with Apple LLVM version 7.3.0 (clang-703.0.31)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.1.1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-opencl --enable-libx264 --enable-libmp3lame --enable-libxvid --enable-libtheora --enable-libvorbis --enable-libvpx --enable-librtmp --enable-libfaac --enable-ffplay --enable-libspeex --enable-openssl --enable-libopus --disable-lzma --enable-nonfree --enable-vda
  
    libavutil      55. 28.100 / 55. 28.100
  
    libavcodec     57. 48.101 / 57. 48.101
  
    libavformat    57. 41.100 / 57. 41.100
  
    libavdevice    57.  0.101 / 57.  0.101
  
    libavfilter     6. 47.100 /  6. 47.100
  
    libavresample   3.  0.  0 /  3.  0.  0
  
    libswscale      4.  1.100 /  4.  1.100
  
    libswresample   2.  1.100 /  2.  1.100
  
    libpostproc    54.  0.100 / 54.  0.100
  
  Supported file protocols:
  
  Input:
  
    async
  
    cache
  
    concat
  
    crypto
  
    data
  
    file
  
    ftp
  
    gopher
  
    hls
  
    http
  
    httpproxy
  
    https
  
    mmsh
  
    mmst
  
    pipe
  
    rtp
  
    srtp
  
    subfile
  
    tcp
  
    tls
  
    udp
  
    udplite
  
    unix
  
    rtmp
  
    rtmpe
  
    rtmps
  
    rtmpt
  
    rtmpte
  
  Output:
  
    crypto
  
    file
  
    ftp
  
    gopher
  
    http
  
    httpproxy
  
    https
  
    icecast
  
    md5
  
    pipe
  
    rtp
  
    srtp
  
    tcp
  
    tls
  
    udp
  
    udplite
  
    unix
  
    rtmp
  
    rtmpe
  
    rtmps
  
    rtmpt
  
    rtmpte