Avoids unneeded interleaving and allows for reusing the AVFrame output buffer
as the internal buffer for 24-bit and 32-bit sample size.

Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>

This will simplify the multi-channel implementation.

It does not need to be unsigned.

It is already unconditionally set to 0 prior to this, so we can modify it
only when needed.

x_modified is just unnecessary, and final_val can be removed by simplifying
the unsigned-to-signed conversion.

avoids some unnecessary arithmetic in certain situations

reduces the number of parameters to decode_scalar() and slightly simplifies
the code

Use the ALACContext fields directly instead.

It is used to store a value read by avio_rb64().

according to the CAF specification:
"... the value for mChunkSize can be greater than the actual valid content
of the packet table chunk"

This provides a more precise identification of the compiler used.
Signed-off-by: Mans Rullgard <mans@mansr.com>

Reversing the lpc coefficient order simplifies indexing in
the filter.
Signed-off-by: Mans Rullgard <mans@mansr.com>

Signed-off-by: Mans Rullgard <mans@mansr.com>

This moves all VP3-specific function pointers from dsputil to a
new vp3dsp context.  There is no reason to ever use the VP3 IDCT
where an MPEG2 IDCT is expected or vice versa.
Signed-off-by: Mans Rullgard <mans@mansr.com>

Signed-off-by: Mans Rullgard <mans@mansr.com>

It turns out that the reference decoder subtracts 128 from DC during block
decode but adds it back during reordering block with zigzag pattern.
Transforming block with incorrect DC caused heavy visual artifacts for
many quantisers.