This commit adds a decoder for the frequency-domain part of USAC.
What works:
- Mono
- Stereo (no prediction)
- Stereo (mid/side coding)
- Stereo (complex prediction)
What's left:
- SBR
- Speech coding
Known issues:
- Desync with certain sequences
- Preroll crossover missing (shouldn't matter, bitrate adaptation only)
AAC uses an unconventional system to send scalefactors
(the volume+quantization value for each band).
Each window is split into either 1 or 8 blocks (long vs short),
and transformed separately from one another, with the coefficients
for each being also completely independent. The scalefactors
slightly increase from 64 (long) to 128 (short) to accomodate
better per-block-per-band volume for each window.
To reduce overhead, the codec signals scalefactor sizes in an obtuse way,
where each group's scalefactor types are sent via a variable length decoding,
with a range.
But our decoder was written in a way where those ranges were carried through
the entire decoder, and to actually read them you had to use the range.
Instead of having a dedicated array with a range for each scalefactor,
just let the decoder directly index each scalefactor.
This also switches the form of quantized scalefactors to the format
the spec uses, where for intensity stereo and regular, scalefactors
are stored in a scalefactor - 100 form, rather than as-is.
USAC gets rid of the complex scalefactor handling. This commit permits
for code sharing between both.
This is achieved by using function pointers for AAC SBR functions.
This unfortunately necessitated to use void* in
ff_aac_sbr_apply(_fixed).
Fixes ticket #10999.
Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This allows to merge it with AACDecDSP.init and remove the latter
(it is called only once anyway); it also allows to make
the fixed/float AACDecDSP and AACDecProc implementations internal
to aacdec_fixed/float.c (which also fixes a violation of our
naming conventions). And it some linker errors when either decoder
is disabled.
Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The code was written in 2012, but seems to have been broken
for just as long. Compilation is broken on every MIPS/MIPS64
system with an FPU (which the code depends on).
The function is called only internally in DSP, so we do not
need to expose it.
apply_ltp on MIPS uses this function, but due to the function
being just a glue function with no real optimizations,
duplicate it there.
Up until now, there was one AACDecContext for the fixed
and one for the floating point decoder. These differed
mostly in certain arrays which were int for the fixed-point
and float for the floating point decoder; there were also
differences in corresponding function pointers.
Yet in order to deduplicate the enormous amount of currently
duplicated code between the float and the fixed-point decoder,
one needs common contexts. Given that int and float have the
same size on all common systems, this commit replaces these
arrays by unions of int arrays and of float arrays. The names
of these arrays have been chosen to be compatible with
AAC_RENAME().
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
sizeof(PredictorState) is different for the floating-point and
the fixed-point AAC decoders; this is an obstacle for deduplicating
code between these decoders. So don't include this array in
SingleChannelElement, instead add a union of pointers to the
fixed-point PredictorState and the floating-point PredictorState.
The actual arrays are part of the extended ChannelElement
to be allocated by ff_aac_sbr_ctx_alloc_init(); it also
sets the pointers.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Up until now, AACDecContext included pointers to one of these
contexts depending upon USE_FIXED. Yet deduplicating
the common parts of the float and fixed-point AAC decoders
needs common structures, so we put both of these pointers
in a union.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The AAC fixed-point and floating-point decoders have
a lot of duplicated code; the main obstacle to
deduplicating it is that several structures with the
same name are actually different types, because
they contain INTFLOATs (int or float) and AAC_FLOATs
(SoftFloat or float). SoftFloat and float typically
have different sizes, so dealing with it is the more
complicated of the two.
AAC_FLOAT is mainly used in the sbr code and structures,
so one can still deduplicate the code by only exposing
the common part of ChannelElement (without SBR context)
to the common decoder part. One prerequisite of this
is to move allocating the whole ChannelElement to
code that will stay unduplicated. It is most natural
to move said allocation to ff_aac_sbr_ctx_init().
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The AAC decoders share no common code with the AAC encoder,
so they are not restricted to using the same structures.
This implies that one can use different structs for each
component and remove elements not used by the decoders/
the encoder. This leads to quite sizeable savings:
sizeof(ChannelElement) for the encoder went down to 134432B
here from 547552B; for the decoder it went down to 512800B.
Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
It is decoder-only; furthermore, there is already
an AACContext in use by libfdk-aacenc.
Also make aacdec.h provide the typedef for AACContext;
up until now, this has been done by sbr.h.
Reviewed-by: Lynne <dev@lynne.ee>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Lynne
Andreas Rheinhardt
James Almer