[Flac-dev] wav to flac corruption

[Justin Waddell]

I have exactly the same problem.

I encoded a BWF file to flac and then then decoded back to wav, using
--keep-foreign-metadata, and I ended up with a bit-perfect copy of the
original BWF. So I was fairly confident that the flac encoding is
working correctly, the problem definitely appears to be with the flac
players.

Unfortunately it seems that the majority of flac players cannot play
24bit files - winamp, windows media player (with flac plugin), vlc,
amarok, kaffeine and a few others ALL failed to play the file. I would
either get silence, static, or a complete refusal to play the file.
The only player that played it successfully was Foobar 2000 on
Windows.

More seriously from my point of view is the Java flac plugin also
fails, which has major repercussions for the project I work on (the
National Archives of Australia Xena project -
http://xena.sourceforge.net).

I don't know how much the flac developers have to do with the player
implementations, but this does seem to be a major problem across
almost the full board of flac players.

J.

On Feb 7, 2008 9:59 AM, Brian Willoughby <brianw at sounds.wa.com> wrote:
> I have one theory about your playback problem: Many flac solutions
> load the entire flac and decompress the samples before passing them
> on to the player.  In your case, the conversion code may be running
> out of memory on 24-bit files where it does not run out of memory on
> 16-bit files of the same duration.  Another possibility is that the
> flac player does not support 24-bit data properly.
>
> As Erik mentioned, conversion to 16-bit is a loss of quality.  Even
> if you are willing to do this, you should have a very good dithering
> algorithm to avoid quantization noise.
>
> The problem you are having is not with flac.  Your problem is with
> your player.  The encode and decoder both support 24-bit files all
> the way up to the 4 GB limit.  I have made several 24-bit multitrack
> recordings, and flac always handles these files without loss of
> data.  The flac players I have fully support long 24-bit files.  It
> seems that you need to replace your player if it cannot handle large
> 24-bit files.
>
> You don't want to reduce the quality of your source or abandon
> lossless coding just because the players are buggy!
>
> Brian Willoughby
> Sound Consulting
>
>