flac dev - Sep 2004 - Questions about FLAC format from a java coder...

Hi,

I'm trying to write a FLAC decoder for my Java audio app. Can I ask a couple
of questions to this list about the format? I think there are a couple of things
not-quite-mentioned in the official spec.

RICE CODING: Which order are Rice-coded numbers stored in? (a)
[sign-bit][low-order bits]["k" zeroes][1]
(b) [sign-bit]["k" zeroes][1][low-order bits]
(c) [sign-bit][low-order bits]["k" ones][0]
(d) [sign-bit]["k" ones][0][low-order bits]
(e) ...?
(And I am I correct in saying the sign bit is 1 for positive, 0 for negative?)

WASTED BITS PER SAMPLE: What does this mean? I can't find a reference to
what my decoder should do with the wasted-bits-per-sample flag.

FRAME BLOCKSIZE: If a frame's BLOCKSIZE is specified as 0000 ("get from
STREAMINFO"), should I use the STREAMINFO "maximum blocksize" or
"minimum blocksize"? Should the two always be equal in this case, and
should I throw an exception if they aren't?

RICE PARTITION SIZE: In a zero-partition-order Rice block, the documentation
says the number of samples in the partition is equal to the frame's
blocksize. Surely this should be equal to the
frame's-blocksize-minus-the-predictor-order, since we shouldn't need to
encode residual for the warmup samples?

Thanks in advance!
Dan Stowell

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On Sun, Oct 05, 2003 at 03:43:08PM +0000, Dan Stowell
wrote:
> I'm trying to write a FLAC decoder for my Java audio app. Can I ask
> a couple of questions to this list about the format? I think there
> are a couple of things not-quite-mentioned in the official spec.
> 
> RICE CODING: Which order are Rice-coded numbers stored in?
> (a) [sign-bit][low-order bits]["k" zeroes][1]
> (b) [sign-bit]["k" zeroes][1][low-order bits]
> (c) [sign-bit][low-order bits]["k" ones][0]
> (d) [sign-bit]["k" ones][0][low-order bits]
> (e) ...?
(e)
["k" zeroes][1][low-order bits][sign-bit]
> (And I am I correct in saying the sign bit is 1 for positive, 0 for
> negative?)
0 for positive, 1 for negative
> WASTED BITS PER SAMPLE: What does this mean? I can't find a
> reference to what my decoder should do with the
> wasted-bits-per-sample flag.
After decoding subframe decoder should bitwise shift all samples to left.
> FRAME BLOCKSIZE: If a frame's BLOCKSIZE is specified as 0000 ("get
> from STREAMINFO"), should I use the STREAMINFO "maximum
blocksize"
> or "minimum blocksize"? Should the two always be equal in this
case,
> and should I throw an exception if they aren't?
It can be used only in fixed block size stream, so both values should
be equal.
> RICE PARTITION SIZE: In a zero-partition-order Rice block, the
> documentation says the number of samples in the partition is equal
> to the frame's blocksize. Surely this should be equal to the
> frame's-blocksize-minus-the-predictor-order, since we shouldn't
need
> to encode residual for the warmup samples?
You are right.

-- 
Miroslav Lichvar