Rockbox

Could remove a 8 KB array (s_fb_intermed) as this was not used anyway, the pointer was overwritten in the codec.

Interesting option after rework: In apps/aac.c and raac.c there are 2 large IRAM arrays defined which are used set to time_out[] and fb_intermed[] in the decoder. The array used for fb_intermed[] can be moved to the decoder library itself and removed in the codec. The array used for time_out[] is problematic: AAC-decoding needs an array size of [2][1024], AAC-HE needs [2][2048]. This array is significant for speed and should therefor be located in IRAM, but there is only enough IRAM for [2][1024] even on targets with larger amount of IRAM. Current solution: A [2][1024] array (gb_time_buffer) is located in IRAM, an additional [2][2048] array (s_time_buffer) is located in RAM. The codec decides if IRAM or RAM can be used. As a result the decoder has [2][1024] = 8 KB of unused IRAM when decoding AAC-HE.
Possible solution: Define generic buffer in IRAM (similar to what malloc did) and decide how to use it depending on AAC/AAC-HE.

   faad_no_malloc_v05.patch (37 KiB)

Moved allocation of time_out[] and fb_intermed[] from apps/codecs to libfaad. Now we have an decodeer-internal solution.

   faad_no_malloc_v07.patch (43.6 KiB)

Three changes:
- Declare qmfs/qmfa direclty in sbr-type, do not use static declarations for those arrays anymore.
- Remove all unneeded _init() and _free() functions.
- Add formerly unused NeAACDecPostSeekReset() to apps/codecs/aac.c

   faad_no_malloc_v11.patch (49.3 KiB)

Same as v11, but I introduced the define FAAD_STATIC_ALLOC (libfaad/common.h) to be able to switch from static to dynamic allocation for AAC-HE related data arrays. Those sum up to ~123 KB for SBR + PS.

Reason for this is that static allocation of those arrays will use this memory always. For AAC-LC files this memory is wasted and will reduce the amount of memory available for m4a tables. This might impact the maximum length of files to be able to play.

   faad_no_malloc_v12.patch (50.1 KiB)

static police…

   faad_no_malloc_v13.patch (53.6 KiB)

Allocate the buffer variables X_left/X_right (now part of the struct XLR) via malloc(), if FAAD_STATIC_ALLOC is not set. This lets the decoder save ~40 KB when decoding AAC-LC files and gives more headroom for the m4a tables of long files.
Only exception: XLR fits into IRAM, in this case always allocate statically. The advantage in speed is ~10 MHz on a nano 2G.

   faad_no_malloc_v14.patch (56.9 KiB)

Resync against r29773.

   faad_no_malloc_v15.patch (58.6 KiB)