[Flac-dev] 96k/24-bit BWF encoding

[Brian Willoughby]

Hi Justin,

I have a suggestion, but it may not be very convenient.  You could  
try converting the 24/96 BWF to AIFF, and then use flac to compress  
the 24/96 AIFF.  There is no difference in audio quality between the  
FLAC file generated from BWF (WAV) vs. AIFF, so perhaps this extra  
step will solve your problem in the short term.  Sorry I haven't used  
BWF or WAV very frequently, but 24/96 AIFF compresses fine, and I  
have verified this on many occasions.

What software are you using to create the BWF?  There was a case on  
the Flac mailing list recently where the WAV file was incorrectly  
formatted, and the same warning appeared.  If that is the case, using  
software which correctly implements the WAV format will give better  
results.

Brian W.


On May 6, 2007, at 17:37, Justin Waddell wrote:

I am attempting to use flac to encode 96k/24-bit broadcast wav (BWF)
files. BWFs are wav files with some extra meta-data chunks, and is the
favoured archival format for many institutions around the world.

These files are encoded successfully by flac, however the resulting
flac file is not playable on all flac players - it plays successfully
in foobar2000 but is silent in winamp, and when using the illuminable
plugin for windows media player it informs me that a codec to play the
file could not be found. Other flac files play successfully in winamp
and windows media player.

The flac encoder does give a warning during the encoding process:

WARNING: legacy WAVE file has format type 1 but bits-per-sample=24

Looking at the specs for WAV files, it appears that for 24-bit files
should have their format code set to WAVE_FORMAT_EXTENSIBLE, but these
files are still set to WAVE_FORMAT_PCM. Could this be the source of
the problem? If not, do you have any other ideas?

I can provide example files if wanted.

Thanks,

Justin