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• 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

  


• 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.

• x264 configure linking and building problems

  16 janvier 2014, par Pie

  I am trying to build x264 from source on Ubuntu 32bit in order to convert a sequence of jpg or png images into mp4 video : x264 site, sample images

  The downloaded binaries is able to convert the sequence into an mkv video (or few other formats) when I run this command :

  ./x264dist ~/Dev/x264emp/img/FLYOVER%4d.JPG -o abc.mkv

  x264dist is the renamed name of the binary I download from the site.

  However, when I grab the source and compile with simple configure :

  $ ./configure --enable-shared --enable-static --enable-pic

  platform:      X86
  
  system:        LINUX
  
  cli:           yes
  
  libx264:       internal
  
  shared:        yes
  
  static:        yes
  
  asm:           yes
  
  interlaced:    yes
  
  avs:           avxsynth
  
  lavf:          no
  
  ffms:          no
  
  mp4:           no
  
  gpl:           yes
  
  thread:        posix
  
  opencl:        yes
  
  filters:       crop select_every 
  
  debug:         no
  
  gprof:         no
  
  strip:         no
  
  PIC:           yes
  
  bit depth:     8
  
  chroma format: all

  then $ make. Then I use the binaries to run the exactly same command as above but there is this error :

  ./x264 ~/Dev/x264emp/img/FLYOVER%4d.JPG -o abc.mkv
  
  raw [error]: raw input requires a resolution.
  
  x264 [error]: could not open input file `/home/tmd/Dev/x264emp/img/FLYOVER%4d.JPG' via any method!

  It seems like it can’t read any input at all. But at least I am still able to run --help on that binaries.

  Then I realized that the downloaded binaries is 3.5Mb while my custom compilation results in 1.5Mb binaries.

  So I just want to know what are the build configurations used by the official build, and/or is there any dependency I am missing that leads to this problem.

  The reason I am trying to build myself because I want to port the x264 lib into Javascript using Emscripten. There has been a solution using FFmpeg but it seems like I don’t need the whole video processing library but only a simple H264 codec. So I need to solve the configure/compile/linking problem to port it rightly.

  Possibly similar How to configure X264 build before running make on OS X