[Libav-user] Encoding to FLAC

Peter Belkner pbelkner at snafu.de
Fri Dec 12 01:03:38 CET 2014


Hello,

I'm trying to encode to FLAC via avcodec/avformat. Unfortunately this 
gives invalid FLACs. I'm following "doc/examples/transcoding.c" which, 
of course, makes the problem reproducible.

If I transcode a valid FLAC to FLAC with the example program "transcode" 
I get a FLAC which is not valid according to the FLAC reference encoder:

 > $ flac -t ./test/output/Track101.flac
 >
 > flac 1.2.1, Copyright (C) 2000,2001,2002,2003,2004,2005,2006,2007  
Josh Coalson
 > flac comes with ABSOLUTELY NO WARRANTY.  This is free software, and 
you are
 > welcome to redistribute it under certain conditions.  Type `flac' for 
details.
 >
 > Track101.flac: ERROR, MD5 signature mismatch

Such a FLAC can't be played with a typical FLAC decoder, but with FFmpeg.

On the other hand, the command line "ffmpeg" program produces valid FLACs.

What's the difference between "ffmpeg" and "transcode"? What's missing 
in "transcode"?

Peter




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