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ffmpeg.wasm-core
Commit 8db1a1dd authored by Michael Niedermayer's avatar Michael Niedermayer
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new bitstream reader API (old get_bits() based one is emulated and will still... 

new bitstream reader API (old get_bits() based one is emulated and will still be supported in the future cuz its simpler)
minor optimizations to get_vlc

Originally committed as revision 725 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 436483c2
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Showing with 340 additions and 521 deletions
libavcodec/common.c
View file @ 8db1a1dd
......@@ -118,101 +118,39 @@ void put_string(PutBitContext * pbc, char *s)
/* bit input functions */
void init_get_bits(GetBitContext *s,
void init_get_bits(GetBitContext *s,
UINT8 *buffer, int buffer_size)
{
#ifdef ALT_BITSTREAM_READER
s->index=0;
s->buffer= buffer;
#else
s->buf = buffer;
s->buf_ptr = buffer;
s->buf_end = buffer + buffer_size;
s->bit_cnt = 0;
s->bit_buf = 0;
while (s->buf_ptr < s->buf_end &&
s->bit_cnt < 32) {
s->bit_buf |= (*s->buf_ptr++ << (24 - s->bit_cnt));
s->bit_cnt += 8;
}
#endif
s->size= buffer_size;
}
#ifndef ALT_BITSTREAM_READER
/* n must be >= 1 and <= 32 */
/* also true: n > s->bit_cnt */
unsigned int get_bits_long(GetBitContext *s, int n)
{
unsigned int val;
int bit_cnt;
unsigned int bit_buf;
#ifdef STATS
st_bit_counts[st_current_index] += n;
s->buffer_end= buffer + buffer_size;
#ifdef ALT_BITSTREAM_READER
s->index=0;
#elif defined LIBMPEG2_BITSTREAM_READER
s->buffer_ptr = buffer;
s->bit_count = 16;
s->cache = 0;
#elif defined A32_BITSTREAM_READER
s->buffer_ptr = (uint32_t*)buffer;
s->bit_count = 32;
s->cache0 = 0;
s->cache1 = 0;
#endif
bit_buf = s->bit_buf;
bit_cnt = s->bit_cnt - n;
// if (bit_cnt >= 0) {
// val = bit_buf >> (32 - n);
// bit_buf <<= n;
// } else
{
UINT8 *buf_ptr;
val = bit_buf >> (32 - n);
buf_ptr = s->buf_ptr;
buf_ptr += 4;
/* handle common case: we can read everything */
if (buf_ptr <= s->buf_end) {
#ifdef ARCH_X86
bit_buf = bswap_32(*((unsigned long*)(&buf_ptr[-4])));
#else
bit_buf = (buf_ptr[-4] << 24) |
(buf_ptr[-3] << 16) |
(buf_ptr[-2] << 8) |
(buf_ptr[-1]);
#endif
val |= bit_buf >> (32 + bit_cnt);
bit_buf <<= - bit_cnt;
bit_cnt += 32;
} else {
buf_ptr -= 4;
bit_buf = 0;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++ << 24;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++ << 16;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++ << 8;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++;
val |= bit_buf >> (32 + bit_cnt);
bit_buf <<= - bit_cnt;
bit_cnt += 8*(buf_ptr - s->buf_ptr);
if(bit_cnt<0) bit_cnt=0;
}
s->buf_ptr = buf_ptr;
OPEN_READER(re, s)
UPDATE_CACHE(re, s)
// UPDATE_CACHE(re, s)
CLOSE_READER(re, s)
}
s->bit_buf = bit_buf;
s->bit_cnt = bit_cnt;
return val;
}
#ifdef A32_BITSTREAM_READER
s->cache1 = 0;
#endif
}
void align_get_bits(GetBitContext *s)
{
#ifdef ALT_BITSTREAM_READER
s->index= (s->index + 7) & (~7);
#else
int n;
n = s->bit_cnt & 7;
if (n > 0) {
get_bits(s, n);
}
#endif
int n= (-get_bits_count(s)) & 7;
if(n) skip_bits(s, n);
}
int check_marker(GetBitContext *s, char *msg)
......@@ -223,55 +161,6 @@ int check_marker(GetBitContext *s, char *msg)
return bit;
}
#ifndef ALT_BITSTREAM_READER
/* This function is identical to get_bits_long(), the */
/* only diference is that it doesn't touch the buffer */
/* it is usefull to see the buffer. */
unsigned int show_bits_long(GetBitContext *s, int n)
{
unsigned int val;
int bit_cnt;
unsigned int bit_buf;
UINT8 *buf_ptr;
bit_buf = s->bit_buf;
bit_cnt = s->bit_cnt - n;
val = bit_buf >> (32 - n);
buf_ptr = s->buf_ptr;
buf_ptr += 4;
/* handle common case: we can read everything */
if (buf_ptr <= s->buf_end) {
#ifdef ARCH_X86
bit_buf = bswap_32(*((unsigned long*)(&buf_ptr[-4])));
#else
bit_buf = (buf_ptr[-4] << 24) |
(buf_ptr[-3] << 16) |
(buf_ptr[-2] << 8) |
(buf_ptr[-1]);
#endif
} else {
buf_ptr -= 4;
bit_buf = 0;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++ << 24;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++ << 16;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++ << 8;
if (buf_ptr < s->buf_end)
bit_buf |= *buf_ptr++;
}
val |= bit_buf >> (32 + bit_cnt);
bit_buf <<= - bit_cnt;
bit_cnt += 32;
return val;
}
#endif
/* VLC decoding */
//#define DEBUG_VLC
......@@ -300,18 +189,15 @@ static int alloc_table(VLC *vlc, int size)
vlc->table_size += size;
if (vlc->table_size > vlc->table_allocated) {
vlc->table_allocated += (1 << vlc->bits);
vlc->table_bits = realloc(vlc->table_bits,
sizeof(INT8) * vlc->table_allocated);
vlc->table_codes = realloc(vlc->table_codes,
sizeof(INT16) * vlc->table_allocated);
if (!vlc->table_bits ||
!vlc->table_codes)
vlc->table = realloc(vlc->table,
sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
if (!vlc->table)
return -1;
}
return index;
}
static int build_table(VLC *vlc, int table_nb_bits,
static int build_table(VLC *vlc, int table_nb_bits,
int nb_codes,
const void *bits, int bits_wrap, int bits_size,
const void *codes, int codes_wrap, int codes_size,
......@@ -319,23 +205,21 @@ static int build_table(VLC *vlc, int table_nb_bits,
{
int i, j, k, n, table_size, table_index, nb, n1, index;
UINT32 code;
INT8 *table_bits;
INT16 *table_codes;
VLC_TYPE (*table)[2];
table_size = 1 << table_nb_bits;
table_index = alloc_table(vlc, table_size);
#ifdef DEBUG_VLC
printf("new table index=%d size=%d code_prefix=%x n=%d\n",
printf("new table index=%d size=%d code_prefix=%x n=%d\n",
table_index, table_size, code_prefix, n_prefix);
#endif
if (table_index < 0)
return -1;
table_bits = &vlc->table_bits[table_index];
table_codes = &vlc->table_codes[table_index];
table = &vlc->table[table_index];
for(i=0;i<table_size;i++) {
table_bits[i] = 0;
table_codes[i] = -1;
table[i][1] = 0; //bits
table[i][0] = -1; //codes
}
/* first pass: map codes and compute auxillary table sizes */
......@@ -360,12 +244,12 @@ static int build_table(VLC *vlc, int table_nb_bits,
printf("%4x: code=%d n=%d\n",
j, i, n);
#endif
if (table_bits[j] != 0) {
if (table[j][1] /*bits*/ != 0) {
fprintf(stderr, "incorrect codes\n");
exit(1);
}
table_bits[j] = n;
table_codes[j] = i;
table[j][1] = n; //bits
table[j][0] = i; //code
j++;
}
} else {
......@@ -376,22 +260,22 @@ static int build_table(VLC *vlc, int table_nb_bits,
j, n);
#endif
/* compute table size */
n1 = -table_bits[j];
n1 = -table[j][1]; //bits
if (n > n1)
n1 = n;
table_bits[j] = -n1;
table[j][1] = -n1; //bits
}
}
}
/* second pass : fill auxillary tables recursively */
for(i=0;i<table_size;i++) {
n = table_bits[i];
n = table[i][1]; //bits
if (n < 0) {
n = -n;
if (n > table_nb_bits) {
n = table_nb_bits;
table_bits[i] = -n;
table[i][1] = -n; //bits
}
index = build_table(vlc, n, nb_codes,
bits, bits_wrap, bits_size,
......@@ -401,9 +285,8 @@ static int build_table(VLC *vlc, int table_nb_bits,
if (index < 0)
return -1;
/* note: realloc has been done, so reload tables */
table_bits = &vlc->table_bits[table_index];
table_codes = &vlc->table_codes[table_index];
table_codes[i] = index;
table = &vlc->table[table_index];
table[i][0] = index; //code
}
}
return table_index;
......@@ -436,8 +319,7 @@ int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
const void *codes, int codes_wrap, int codes_size)
{
vlc->bits = nb_bits;
vlc->table_bits = NULL;
vlc->table_codes = NULL;
vlc->table = NULL;
vlc->table_allocated = 0;
vlc->table_size = 0;
#ifdef DEBUG_VLC
......@@ -448,8 +330,7 @@ int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
bits, bits_wrap, bits_size,
codes, codes_wrap, codes_size,
0, 0) < 0) {
av_free(vlc->table_bits);
av_free(vlc->table_codes);
av_free(vlc->table);
return -1;
}
return 0;
......@@ -458,8 +339,7 @@ int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
void free_vlc(VLC *vlc)
{
av_free(vlc->table_bits);
av_free(vlc->table_codes);
av_free(vlc->table);
}
int ff_gcd(int a, int b){
......
libavcodec/common.h
View file @ 8db1a1dd
This diff is collapsed.
libavcodec/mpeg12.c
View file @ 8db1a1dd
......@@ -961,21 +961,20 @@ static int mpeg1_decode_block(MpegEncContext *s,
dprintf("dc=%d diff=%d\n", dc, diff);
i = 1;
} else {
int bit_cnt, v;
UINT32 bit_buf;
UINT8 *buf_ptr;
int v;
OPEN_READER(re, &s->gb);
i = 0;
/* special case for the first coef. no need to add a second vlc table */
SAVE_BITS(&s->gb);
SHOW_BITS(&s->gb, v, 2);
UPDATE_CACHE(re, &s->gb);
v= SHOW_UBITS(re, &s->gb, 2);
if (v & 2) {
run = 0;
level = 1 - ((v & 1) << 1);
FLUSH_BITS(2);
RESTORE_BITS(&s->gb);
SKIP_BITS(re, &s->gb, 2);
CLOSE_READER(re, &s->gb);
goto add_coef;
}
RESTORE_BITS(&s->gb);
CLOSE_READER(re, &s->gb);
}
/* now quantify & encode AC coefs */
......@@ -1035,26 +1034,25 @@ static int mpeg2_decode_block_non_intra(MpegEncContext *s,
mismatch = 1;
{
int bit_cnt, v;
UINT32 bit_buf;
UINT8 *buf_ptr;
int v;
OPEN_READER(re, &s->gb);
i = 0;
if (n < 4)
if (n < 4)
matrix = s->inter_matrix;
else
matrix = s->chroma_inter_matrix;
/* special case for the first coef. no need to add a second vlc table */
SAVE_BITS(&s->gb);
SHOW_BITS(&s->gb, v, 2);
UPDATE_CACHE(re, &s->gb);
v= SHOW_UBITS(re, &s->gb, 2);
if (v & 2) {
run = 0;
level = 1 - ((v & 1) << 1);
FLUSH_BITS(2);
RESTORE_BITS(&s->gb);
SKIP_BITS(re, &s->gb, 2);
CLOSE_READER(re, &s->gb);
goto add_coef;
}
RESTORE_BITS(&s->gb);
CLOSE_READER(re, &s->gb);
}
/* now quantify & encode AC coefs */
......
libavcodec/mpegaudiodec.c
View file @ 8db1a1dd
......@@ -1457,11 +1457,8 @@ static void seek_to_maindata(MPADecodeContext *s, long backstep)
UINT8 *ptr;
/* compute current position in stream */
#ifdef ALT_BITSTREAM_READER
ptr = s->gb.buffer + (s->gb.index>>3);
#else
ptr = s->gb.buf_ptr - (s->gb.bit_cnt >> 3);
#endif
ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);
/* copy old data before current one */
ptr -= backstep;
memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] +
......@@ -1547,9 +1544,7 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
{
int s_index;
int linbits, code, x, y, l, v, i, j, k, pos;
UINT8 *last_buf_ptr;
UINT32 last_bit_buf;
int last_bit_cnt;
GetBitContext last_gb;
VLC *vlc;
UINT8 *code_table;
......@@ -1608,36 +1603,20 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
/* high frequencies */
vlc = &huff_quad_vlc[g->count1table_select];
last_buf_ptr = NULL;
last_bit_buf = 0;
last_bit_cnt = 0;
last_gb.buffer = NULL;
while (s_index <= 572) {
pos = get_bits_count(&s->gb);
if (pos >= end_pos) {
if (pos > end_pos && last_buf_ptr != NULL) {
if (pos > end_pos && last_gb.buffer != NULL) {
/* some encoders generate an incorrect size for this
part. We must go back into the data */
s_index -= 4;
#ifdef ALT_BITSTREAM_READER
s->gb.buffer = last_buf_ptr;
s->gb.index = last_bit_cnt;
#else
s->gb.buf_ptr = last_buf_ptr;
s->gb.bit_buf = last_bit_buf;
s->gb.bit_cnt = last_bit_cnt;
#endif
s->gb = last_gb;
}
break;
}
#ifdef ALT_BITSTREAM_READER
last_buf_ptr = s->gb.buffer;
last_bit_cnt = s->gb.index;
#else
last_buf_ptr = s->gb.buf_ptr;
last_bit_buf = s->gb.bit_buf;
last_bit_cnt = s->gb.bit_cnt;
#endif
last_gb= s->gb;
code = get_vlc(&s->gb, vlc);
dprintf("t=%d code=%d\n", g->count1table_select, code);
if (code < 0)
......
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