[Flac-dev] Decoding Type=Independent

MVallevand mvallevand at gmail.com
Mon Jan 1 21:37:01 PST 2007

Hello, I am new to the list, to FLAC and to FLAC development but I am
having a problem in trying to make FLAC work with MediaMVP based the
mvpmc project (ref.  http://www.wvpmc.org) that hopefully someone can
help me with.  This device is possibly minimum spec. for a FLAC

In any case, I have had some success cross-compiling libFLAC  (without
the ogg or metadata modules).for the embedded environment upon which
mvpmc is based. In fact according to top the CPU utilization for FLAC
decoding and playing is only 10%.  I was very please and was going to
release a beta release to our developers when I noticed that the code
I use (based on the test_libFLAC encoders.c program and flac123.c)
would not play "type =INDEPENDENT" files.

The way the MediaMVP device works is there is an onboard audio
processor which can decode PCM (in either OggVorbis or MS WAV formats)
, various MPEG, and AC3.  Basically for the LPC type I just write()
the date to the hardware file descriptor and it seems to play fine.
When the INDEPENDENT data is written this way, I can just make out the
song through the noise and static and the speed is reduced.

Right now I've spent a lot of time trying to playing with blocksize,
samples, and channels but I can't seem to get these files to work.
Can anyone point me to sample code (no floating point on this device)
which would explain how to transform the INDEPENDENT sample frames  to
LPC.  Obviously preserving lossless is important for this logic too.

Thanks in advance.


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