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• FFmpeg Has A Native VP8 Decoder

  24 juin 2010, par Multimedia Mike — VP8

  Thanks to David Conrad and Ronald Bultje who committed their native VP8 video decoder to the FFmpeg codebase yesterday. At this point, it can decode 14/17 of the VP8 test vectors that Google released during the initial open sourcing event. Work is ongoing on those 3 non-passing samples (missing bilinear filter). Meanwhile, FFmpeg’s optimization-obsessive personalities are hard at work optimizing the native decoder. The current decoder is already profiled to be faster than Google/On2’s official libvpx.

  Testing
  So it falls to FATE to test this on the ridiculous diversity of platforms that FFmpeg supports. I staged individual test specs for each of the 17 test vectors : vp8-test-vector-001 ... vp8-test-vector-017. After the samples have propagated through to the various FATE installations, I’ll activate the 14 test specs that are currently passing.

  Initial Testing Methodology
  Inspired by Ronald Bultje’s idea, I built the latest FFmpeg-SVN with libvpx enabled. Then I selected between the reference and native decoders as such :

  $ for i in 001 002 003 004 005 006 007 008 009 \
   010 011 012 013 014 015 016 017
  do
    echo vp80-00-comprehensive-$i.ivf
    ffmpeg -vcodec libvpx -i \
      /path/to/vp8-test-vectors-r1/vp80-00-comprehensive-$i.ivf \
      -f framemd5 - 2> /dev/null
  done > refs.txt
  $ for i in 001 002 003 004 005 006 007 008 009 \
  
   010 011 012 013 014 015 016 017
  
  do
  
    echo vp80-00-comprehensive-$i.ivf
  
    ffmpeg -vcodec vp8 -i \
  
      /path/to/vp8-test-vectors-r1/vp80-00-comprehensive-$i.ivf \
  
      -f framemd5 - 2> /dev/null
  
  done > native.txt
  $ diff -u refs.txt native.txt
  

  That reveals precisely which files differ.

• convert WAV to TETRA format

  14 juin 2020, par Ashish Arora

  I am trying to convert a wav file into TETRA encoded file (https://en.wikipedia.org/wiki/Terrestrial_Trunked_Radio). Tetra is used by fire-fighters, it provides a radio-like voice.

  



  I am trying to use the official tetra codec codes available at (https://www.etsi.org/deliver/etsi_en/300300_300399/30039502/01.03.01_60/) and we can easily compile it using the scripts available at https://github.com/sq5bpf/install-tetra-codec.

  



  However, I am not able to figure out how to convert a wav file into tetra codec files using these files. I tried going through the documentation of the compiled files (ccoder, cdecoder, scoder, sdecoder).

  



  I tried the following command -

  



  


  tetra/bin/scoder input.wav serial_file synth_file

  


  



  here serial_file and synth_file are the output files and have following documentation in the scoder.c file :

  



      INPUT   :   - Description : speech file to be analyzed
                - Format : binary file 16 bit-samples
                  240 samples per frame

serial_file :   - Description : serial stream output file 
            - Format : binary file 16 bit-samples
              each 16 bit-sample represents one encoded bit
              138 (= 1 + 137) bits per frame

synth_file  :   - Description : local synthesis output file 
            - Format : binary file 16 bit-samples


  



  For an input file of size 13M, I obtained serial_file and synth_file of size 8.0M and 16M. However, I thought since the wav file is getting converted into a walkie-talkie type signal the output file size will be alot smaller.

  



  I want to clarify if :

  



  

  • I used the correct code to convert an input wav file into a tetra format output file.

  


  • can you please help me understand, what is serial_file and synth_file.

  


  



  Thanks,
Ashish

  


• 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