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| author | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-11-18 02:19:53 +0100 |
|---|---|---|
| committer | Andreas Rheinhardt <andreas.rheinhardt@gmail.com> | 2020-12-08 17:51:47 +0100 |
| commit | ed33bbe678730ef1ffde77f20eb4c6afb7a6902c (patch) | |
| tree | a46f589b105fca7f4290023d17474e12e98ad01e /libavcodec/mpegaudiodec_fixed.c | |
| parent | 12e941df89aa0e2aa8c6b90bfef9d4127ae7063c (diff) | |
avcodec/mpegaudiodec: Hardcode tables to save space
The csa_tables (which always consist of 32 entries of four byte each,
but the type depends upon whether the decoder is fixed or
floating-point) are currently initialized once during decoder
initialization; yet it turns out that this is actually no benefit: The
code used to initialize these tables takes up 153 (fixed point) and 122
(floating point) bytes when compiled with GCC 9.3 with -O3 on x64, so it
is better to just hardcode these tables.
Essentially the same applies to the is_tables: They have a size of 128B
each and the code to initialize them occupies 149 (fixed point) resp.
140 (floating point) bytes. So hardcode them, too.
To make the origin of the tables clear, references to the code used to
create them have been added.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Diffstat (limited to 'libavcodec/mpegaudiodec_fixed.c')
| -rw-r--r-- | libavcodec/mpegaudiodec_fixed.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/libavcodec/mpegaudiodec_fixed.c b/libavcodec/mpegaudiodec_fixed.c index 6fe372b38f..a3c8ddc21e 100644 --- a/libavcodec/mpegaudiodec_fixed.c +++ b/libavcodec/mpegaudiodec_fixed.c @@ -36,6 +36,26 @@ #define OUT_FMT AV_SAMPLE_FMT_S16 #define OUT_FMT_P AV_SAMPLE_FMT_S16P +/* Intensity stereo table. See commit b91d46614df189e7905538e7f5c4ed9c7ed0d274 + * (float based mp1/mp2/mp3 decoders.) for how they were created. */ +static const int32_t is_table[2][16] = { + { 0x000000, 0x1B0CB1, 0x2ED9EC, 0x400000, 0x512614, 0x64F34F, 0x800000 }, + { 0x800000, 0x64F34F, 0x512614, 0x400000, 0x2ED9EC, 0x1B0CB1, 0x000000 } +}; + +/* Antialiasing table. See commit ce4a29c066cddfc180979ed86396812f24337985 + * (optimize antialias) for how they were created. */ +static const int32_t csa_table[8][4] = { + { 0x36E129F8, 0xDF128056, 0x15F3AA4E, 0xA831565E }, + { 0x386E75F2, 0xE1CF24A5, 0x1A3D9A97, 0xA960AEB3 }, + { 0x3CC6B73A, 0xEBF19FA6, 0x28B856E0, 0xAF2AE86C }, + { 0x3EEEA054, 0xF45B88BC, 0x334A2910, 0xB56CE868 }, + { 0x3FB6905C, 0xF9F27F18, 0x39A90F74, 0xBA3BEEBC }, + { 0x3FF23F20, 0xFD60D1E4, 0x3D531104, 0xBD6E92C4 }, + { 0x3FFE5932, 0xFF175EE4, 0x3F15B816, 0xBF1905B2 }, + { 0x3FFFE34A, 0xFFC3612F, 0x3FC34479, 0xBFC37DE5 } +}; + #include "mpegaudiodec_template.c" #if CONFIG_MP1_DECODER |