unknown codec 0x0064 (G726 ADPCM)

I've got a number of audio recordings which I can't play back. It appears to be a case of a missing codec, but I can't locate the codec in question.

VLC will not play the files. ffmpeg gives the error Unsupported codec (id=0) for input stream 0.

This is the output from MediaInfo.

General
CompleteName                     : 

Format                           : Wave
FileSize/String                  : 164 KiB
Duration/String                  : 1mn 24s
OverallBitRate/String            : 16.0 Kbps

Audio
Format                           : ADPCM
CodecID                          : 64
CodecID/Info                     : G.726
CodecID/Hint                     : APICOM
Duration/String                  : 1mn 24s
BitRate_Mode/String              : Constant
BitRate/String                   : 16.0 Kbps
Channel(s)/String                : 1 channel
SamplingRate/String              : 8 000 Hz
BitDepth/String                  : 2 bits
StreamSize/String                : 164 KiB (100%)

Can anyone help?

Colin Pickard

Posted 2010-05-28T10:45:28.867

Reputation: 6 774

Answers

https://stackoverflow.com/questions/2508717/how-do-i-convert-a-g-726-adpcm-signal-into-a-pcm-signal

Ignacio Vazquez-Abrams

Posted 2010-05-28T10:45:28.867

Reputation: 100 516

this is very interesting, thank you. I've been playing with the settings of decode-g72x and it does produce an audible wav, but so far the audio is garbled. I shall keep playing... – Colin Pickard – 2010-05-28T11:20:01.530

It turned out that this method would actually work, if the source files were not corrupted... Thank you – Colin Pickard – 2010-09-17T13:32:28.763

This is a long shot, but I got some results before by Importing the file into Audacity, via the Project menu -> "Import Raw Data". ADPCM is there in the list, just match up the sampling rate and any other fields, and try different byte-orders if you get bad results.

invert

Posted 2010-05-28T10:45:28.867

Reputation: 4 918