Opened 5 years ago

Last modified 18 months ago

#1959 open enhancement

Support codec2

Reported by: Mathias Owned by:
Priority: wish Component: avcodec
Version: git-master Keywords: codec2
Cc: Blocked By:
Blocking: Reproduced by developer: yes
Analyzed by developer: no


Summary of the bug: Codec2 is a voice compression codec aiming towards very low bandwiths (below 5000 bits per second). Profiles exist for 3200, 2400, 1400 and 1200 bps.

I would suggest adding Codec2 to the list of supported ffmpeg audio compression and decompression codecs.

Codec2 is LGPL licensed and was designed to avoid patent issues.

URL for more information:

Change History (8)

comment:1 Changed 5 years ago by cehoyos

  • Component changed from FFmpeg to avcodec
  • Keywords codec2 added
  • Reproduced by developer set
  • Status changed from new to open
  • Summary changed from Add codec2 to the list of supported voice codecs to Support codec2
  • Version changed from unspecified to git-master

comment:2 Changed 2 years ago by richardpl

Are there actual samples anywhere?

comment:3 Changed 21 months ago by Lowe1289

If you want to get access to some Codec 2 sample files I've posted the first 12 chapters of Sherlock Homes Audio book in Codec 2 format (.c2) here: - enjoy.

comment:4 Changed 20 months ago by Lowe1289

Another audiobook Codec2 file batch here - Do Androids Dream of Electric Sheep by Philip K. Dick:

comment:5 Changed 20 months ago by richardpl

How it this .c2 format related to which supports multiple profiles?

comment:6 Changed 20 months ago by Lowe1289

Hmm, I'm not sure - I used an old windows compiled codec2 encoder binary provided here ( which outputs files with the .c2 extension - at 2400bps I'm guessing (I talk about the process to do this here:

I assume the different codec2 profiles were just different bitrates, similar to mp3 having different bitrates..

Last edited 20 months ago by Lowe1289 (previous) (diff)

comment:7 Changed 20 months ago by richardpl

Unfortunately it is not, your files have nothing to do with original codec2.

comment:8 Changed 20 months ago by Lowe1289

Ok for what it's worth I've updated the audiobooks Codec .C2 files using the official source code from (using the functions c2enc and c2dec which are documented in the readme file located at ​ Bitrates used are 2400 and 1400bps and should be mentioned on the audiobook pages now and in the file names. Profile used were the default of v0.3.

Turns out the previous windows binaries I was using were based on a 0.1alpha version of Codec2 and therefore not very forward compatible. Anyway should work now.

Last edited 18 months ago by Lowe1289 (previous) (diff)
Note: See TracTickets for help on using tickets.