[Flac-dev] Lossless audio codecs for video editing

[Miroslav Lichvar]

On Fri, Feb 11, 2005 at 11:57:58AM -0800, Josh Coalson wrote:
> I am contemplating fixing this problem in the format eventually
> (along with others) but older decoders will not be able to read
> such streams, so if I do it, it will have to be done carefully
> to avoid disrupting users.  I would bundle it up with other
> format changes and compression increases.

Would it be possible to add to your list a modification of partitioned
rice coding? Something like this:

 RESIDUAL_CODING_METHOD_PARTITIONED_RICE

   <4>              Partition order.
-  RICE_PARTITION+  There will be 2^order partitions.
+  RICE_PARTITION+  There will be
+                   (frame's blocksize - prediction order + s - 1) / s
+                   partitions, where s = frame's blocksize / 2^order
+                   is partition size.

 RICE_PARTITION

   <4(+5)> ...

   <?>  Encoded residual. The number of samples (n) in the partition is
        determined as follows:
 
        * if the partition order is zero, n = frame's blocksize -
          predictor order
        * else if this is not the first partition of the subframe,
          n = (frame's blocksize / (2^partition order))
-       * else n = (frame's blocksize / (2^partition order)) -
-         predictor order
+       * else n = (frame's blocksize - prediction order) % s


It would not break decoding of old files and it would allow:

* partition size <= prediction order, not really useful though
* reasonable partitioning for frames with blocksize != 2^something,
  would be good for variable blocksize coding

-- 
Miroslav Lichvar