mirror of https://git.ffmpeg.org/ffmpeg.git
bitstream: Move VLC reading functions into the vlc.h header
This makes the bitstream.h header leaner. Signed-off-by: Diego Biurrun <diego@biurrun.de>
This commit is contained in:
Luca Barbato
Diego Biurrun
parent
73fc82f343
commit
0ac1fec1c3
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@ -33,7 +33,6 @@
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#include "libavutil/log.h"
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#include "mathops.h"
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#include "vlc.h"
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typedef struct BitstreamContext {
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uint64_t bits; // stores bits read from the buffer
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@ -287,78 +286,6 @@ static inline int bitstream_read_xbits(BitstreamContext *bc, unsigned length)
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return ((((uint32_t)(sign ^ cache)) >> (32 - length)) ^ sign) - sign;
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}
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/* Return the LUT element for the given bitstream configuration. */
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static inline int set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits,
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VLC_TYPE (*table)[2])
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{
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unsigned idx;
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*nb_bits = -*n;
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idx = bitstream_peek(bc, *nb_bits) + code;
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*n = table[idx][1];
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return table[idx][0];
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}
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/**
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* Parse a VLC code.
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* @param bits is the number of bits which will be read at once, must be
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* identical to nb_bits in init_vlc()
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* @param max_depth is the number of times bits bits must be read to completely
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* read the longest VLC code
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* = (max_vlc_length + bits - 1) / bits
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* If the VLC code is invalid and max_depth = 1, then no bits will be removed.
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* If the VLC code is invalid and max_depth > 1, then the number of bits removed
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* is undefined. */
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static inline int bitstream_read_vlc(BitstreamContext *bc, VLC_TYPE (*table)[2],
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int bits, int max_depth)
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{
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int nb_bits;
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unsigned idx = bitstream_peek(bc, bits);
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int code = table[idx][0];
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int n = table[idx][1];
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if (max_depth > 1 && n < 0) {
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skip_remaining(bc, bits);
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code = set_idx(bc, code, &n, &nb_bits, table);
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if (max_depth > 2 && n < 0) {
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skip_remaining(bc, nb_bits);
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code = set_idx(bc, code, &n, &nb_bits, table);
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}
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}
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skip_remaining(bc, n);
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return code;
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}
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#define BITSTREAM_RL_VLC(level, run, bc, table, bits, max_depth) \
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do { \
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int n, nb_bits; \
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unsigned index = bitstream_peek(bc, bits); \
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level = table[index].level; \
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n = table[index].len; \
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\
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if (max_depth > 1 && n < 0) { \
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bitstream_skip(bc, bits); \
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\
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nb_bits = -n; \
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\
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index = bitstream_peek(bc, nb_bits) + level; \
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level = table[index].level; \
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n = table[index].len; \
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if (max_depth > 2 && n < 0) { \
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bitstream_skip(bc, nb_bits); \
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nb_bits = -n; \
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\
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index = bitstream_peek(bc, nb_bits) + level; \
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level = table[index].level; \
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n = table[index].len; \
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} \
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} \
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run = table[index].run; \
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bitstream_skip(bc, n); \
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} while (0)
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/* Return decoded truncated unary code for the values 0, 1, 2. */
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static inline int bitstream_decode012(BitstreamContext *bc)
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{
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@ -21,6 +21,8 @@
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#include <stdint.h>
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#include "bitstream.h"
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#define VLC_TYPE int16_t
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typedef struct VLC {
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@ -62,4 +64,76 @@ void ff_free_vlc(VLC *vlc);
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init_vlc(vlc, bits, a, b, c, d, e, f, g, INIT_VLC_USE_NEW_STATIC); \
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} while (0)
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/* Return the LUT element for the given bitstream configuration. */
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static inline int set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits,
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VLC_TYPE (*table)[2])
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{
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unsigned idx;
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*nb_bits = -*n;
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idx = bitstream_peek(bc, *nb_bits) + code;
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*n = table[idx][1];
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return table[idx][0];
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}
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/**
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* Parse a VLC code.
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* @param bits is the number of bits which will be read at once, must be
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* identical to nb_bits in init_vlc()
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* @param max_depth is the number of times bits bits must be read to completely
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* read the longest VLC code
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* = (max_vlc_length + bits - 1) / bits
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* If the VLC code is invalid and max_depth = 1, then no bits will be removed.
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* If the VLC code is invalid and max_depth > 1, then the number of bits removed
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* is undefined. */
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static inline int bitstream_read_vlc(BitstreamContext *bc, VLC_TYPE (*table)[2],
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int bits, int max_depth)
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{
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int nb_bits;
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unsigned idx = bitstream_peek(bc, bits);
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int code = table[idx][0];
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int n = table[idx][1];
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if (max_depth > 1 && n < 0) {
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skip_remaining(bc, bits);
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code = set_idx(bc, code, &n, &nb_bits, table);
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if (max_depth > 2 && n < 0) {
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skip_remaining(bc, nb_bits);
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code = set_idx(bc, code, &n, &nb_bits, table);
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}
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}
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skip_remaining(bc, n);
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return code;
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}
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#define BITSTREAM_RL_VLC(level, run, bc, table, bits, max_depth) \
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do { \
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int n, nb_bits; \
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unsigned index = bitstream_peek(bc, bits); \
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level = table[index].level; \
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n = table[index].len; \
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\
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if (max_depth > 1 && n < 0) { \
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bitstream_skip(bc, bits); \
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\
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nb_bits = -n; \
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\
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index = bitstream_peek(bc, nb_bits) + level; \
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level = table[index].level; \
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n = table[index].len; \
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if (max_depth > 2 && n < 0) { \
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bitstream_skip(bc, nb_bits); \
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nb_bits = -n; \
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\
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index = bitstream_peek(bc, nb_bits) + level; \
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level = table[index].level; \
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n = table[index].len; \
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} \
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} \
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run = table[index].run; \
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bitstream_skip(bc, n); \
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} while (0)
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#endif /* AVCODEC_VLC_H */
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