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Code Issues Releases Activity

avcodec/proresdec: Don't use LONG_BITSTREAM_READER

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Using LONG_BITSTREAM_READER means that every get_bits() call
uses an AV_RB64() to ensure that cache always contains 32 valid bits
(as opposed to the ordinary 25 guaranteed by reading 32 bits);
yet this is unnecessary when unpacking alpha. So only use these
64bit reads where necessary.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt
2025-02-23 23:21:00 +01:00
parent ee1408cd66
commit 8ad2daec58
1 changed files with 3 additions and 5 deletions
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8
libavcodec/proresdec.c
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@@ -26,8 +26,6 @@
//#define DEBUG //#define DEBUG
#define LONG_BITSTREAM_READER
#include "config_components.h" #include "config_components.h"
#include "libavutil/internal.h" #include "libavutil/internal.h"
@@ -428,7 +426,7 @@ static int decode_picture_header(AVCodecContext *avctx, const uint8_t *buf, cons
unsigned int rice_order, exp_order, switch_bits; \ unsigned int rice_order, exp_order, switch_bits; \
unsigned int q, buf, bits; \ unsigned int q, buf, bits; \
\ \
UPDATE_CACHE(re, gb); \ UPDATE_CACHE_32(re, gb); /* We really need 32 bits */ \
buf = GET_CACHE(re, gb); \ buf = GET_CACHE(re, gb); \
\ \
/* number of bits to switch between rice and exp golomb */ \ /* number of bits to switch between rice and exp golomb */ \
@@ -440,7 +438,7 @@ static int decode_picture_header(AVCodecContext *avctx, const uint8_t *buf, cons
\ \
if (q > switch_bits) { /* exp golomb */ \ if (q > switch_bits) { /* exp golomb */ \
bits = exp_order - switch_bits + (q<<1); \ bits = exp_order - switch_bits + (q<<1); \
if (bits > FFMIN(MIN_CACHE_BITS, 31)) \ if (bits > 31) \
return AVERROR_INVALIDDATA; \ return AVERROR_INVALIDDATA; \
val = SHOW_UBITS(re, gb, bits) - (1 << exp_order) + \ val = SHOW_UBITS(re, gb, bits) - (1 << exp_order) + \
((switch_bits + 1) << rice_order); \ ((switch_bits + 1) << rice_order); \
@@ -502,7 +500,7 @@ static av_always_inline int decode_ac_coeffs(AVCodecContext *avctx, GetBitContex
int log2_block_count = av_log2(blocks_per_slice); int log2_block_count = av_log2(blocks_per_slice);
OPEN_READER(re, gb); OPEN_READER(re, gb);
UPDATE_CACHE(re, gb); \ UPDATE_CACHE_32(re, gb);
run = 4; run = 4;
level = 2; level = 2;