mirror of https://git.ffmpeg.org/ffmpeg.git
LE bitstream reader based upon a patch by (Balatoni Denes <dbalatoni programozo hu)
Originally committed as revision 4215 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer
parent
0de1318a29
commit
cea27ac714
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@ -132,14 +132,14 @@ static int build_table(VLC *vlc, int table_nb_bits,
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int nb_codes,
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const void *bits, int bits_wrap, int bits_size,
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const void *codes, int codes_wrap, int codes_size,
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uint32_t code_prefix, int n_prefix, int use_static)
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uint32_t code_prefix, int n_prefix, int flags)
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{
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int i, j, k, n, table_size, table_index, nb, n1, index;
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int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2;
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uint32_t code;
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VLC_TYPE (*table)[2];
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table_size = 1 << table_nb_bits;
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table_index = alloc_table(vlc, table_size, use_static);
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table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_STATIC);
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#ifdef DEBUG_VLC
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printf("new table index=%d size=%d code_prefix=%x n=%d\n",
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table_index, table_size, code_prefix, n_prefix);
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@ -165,12 +165,18 @@ static int build_table(VLC *vlc, int table_nb_bits,
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#endif
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/* if code matches the prefix, it is in the table */
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n -= n_prefix;
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if (n > 0 && (code >> n) == code_prefix) {
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if(flags & INIT_VLC_LE)
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code_prefix2= code & (n_prefix>=32 ? 0xffffffff : (1 << n_prefix)-1);
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else
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code_prefix2= code >> n;
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if (n > 0 && code_prefix2 == code_prefix) {
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if (n <= table_nb_bits) {
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/* no need to add another table */
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j = (code << (table_nb_bits - n)) & (table_size - 1);
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nb = 1 << (table_nb_bits - n);
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for(k=0;k<nb;k++) {
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if(flags & INIT_VLC_LE)
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j = (code >> n_prefix) + (k<<n);
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#ifdef DEBUG_VLC
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av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
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j, i, n);
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@ -185,7 +191,7 @@ static int build_table(VLC *vlc, int table_nb_bits,
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}
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} else {
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n -= table_nb_bits;
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j = (code >> n) & ((1 << table_nb_bits) - 1);
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j = (code >> ((flags & INIT_VLC_LE) ? n_prefix : n)) & ((1 << table_nb_bits) - 1);
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#ifdef DEBUG_VLC
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printf("%4x: n=%d (subtable)\n",
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j, n);
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@ -211,8 +217,8 @@ static int build_table(VLC *vlc, int table_nb_bits,
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index = build_table(vlc, n, nb_codes,
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bits, bits_wrap, bits_size,
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codes, codes_wrap, codes_size,
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(code_prefix << table_nb_bits) | i,
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n_prefix + table_nb_bits, use_static);
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(flags & INIT_VLC_LE) ? (code_prefix | (i << n_prefix)) : ((code_prefix << table_nb_bits) | i),
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n_prefix + table_nb_bits, flags);
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if (index < 0)
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return -1;
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/* note: realloc has been done, so reload tables */
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@ -368,6 +368,16 @@ static inline int unaligned32_be(const void *v)
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#endif
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}
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static inline int unaligned32_le(const void *v)
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{
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#ifdef CONFIG_ALIGN
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const uint8_t *p=v;
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return (((p[3]<<8) | p[2])<<16) | (p[1]<<8) | (p[0]);
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#else
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return le2me_32( unaligned32(v)); //original
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#endif
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}
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#ifdef ALT_BITSTREAM_READER
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# define MIN_CACHE_BITS 25
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@ -378,11 +388,19 @@ static inline int unaligned32_be(const void *v)
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# define CLOSE_READER(name, gb)\
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(gb)->index= name##_index;\
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# ifdef ALT_BITSTREAM_READER_LE
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# define UPDATE_CACHE(name, gb)\
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name##_cache= unaligned32_le( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) >> (name##_index&0x07);\
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# define SKIP_CACHE(name, gb, num)\
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name##_cache >>= (num);
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# else
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# define UPDATE_CACHE(name, gb)\
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name##_cache= unaligned32_be( ((const uint8_t *)(gb)->buffer)+(name##_index>>3) ) << (name##_index&0x07);\
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# define SKIP_CACHE(name, gb, num)\
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name##_cache <<= (num);\
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name##_cache <<= (num);
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# endif
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// FIXME name?
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# define SKIP_COUNTER(name, gb, num)\
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@ -397,8 +415,13 @@ static inline int unaligned32_be(const void *v)
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# define LAST_SKIP_BITS(name, gb, num) SKIP_COUNTER(name, gb, num)
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# define LAST_SKIP_CACHE(name, gb, num) ;
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# ifdef ALT_BITSTREAM_READER_LE
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# define SHOW_UBITS(name, gb, num)\
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((name##_cache) & (NEG_USR32(0xffffffff,num)))
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# else
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# define SHOW_UBITS(name, gb, num)\
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NEG_USR32(name##_cache, num)
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# endif
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# define SHOW_SBITS(name, gb, num)\
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NEG_SSR32(name##_cache, num)
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@ -616,8 +639,13 @@ static inline unsigned int get_bits1(GetBitContext *s){
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#ifdef ALT_BITSTREAM_READER
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int index= s->index;
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uint8_t result= s->buffer[ index>>3 ];
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#ifdef ALT_BITSTREAM_READER_LE
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result>>= (index&0x07);
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result&= 1;
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#else
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result<<= (index&0x07);
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result>>= 8 - 1;
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#endif
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index++;
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s->index= index;
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@ -687,7 +715,9 @@ void align_get_bits(GetBitContext *s);
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int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
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const void *bits, int bits_wrap, int bits_size,
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const void *codes, int codes_wrap, int codes_size,
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int use_static);
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int flags);
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#define INIT_VLC_USE_STATIC 1
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#define INIT_VLC_LE 2
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void free_vlc(VLC *vlc);
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/**
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