355 lines
9.8 KiB
C
355 lines
9.8 KiB
C
/*
|
|
* Common bit i/o utils
|
|
* Copyright (c) 2000, 2001 Fabrice Bellard.
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*
|
|
* alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
|
|
*/
|
|
#include "avcodec.h"
|
|
|
|
const UINT8 ff_sqrt_tab[128]={
|
|
0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5,
|
|
5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
|
|
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
|
|
9, 9, 9, 9,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,11,11,11,11,11,11,11
|
|
};
|
|
|
|
void init_put_bits(PutBitContext *s,
|
|
UINT8 *buffer, int buffer_size,
|
|
void *opaque,
|
|
void (*write_data)(void *, UINT8 *, int))
|
|
{
|
|
s->buf = buffer;
|
|
s->buf_end = s->buf + buffer_size;
|
|
s->data_out_size = 0;
|
|
if(write_data!=NULL)
|
|
{
|
|
fprintf(stderr, "write Data callback is not supported\n");
|
|
}
|
|
#ifdef ALT_BITSTREAM_WRITER
|
|
s->index=0;
|
|
((uint32_t*)(s->buf))[0]=0;
|
|
// memset(buffer, 0, buffer_size);
|
|
#else
|
|
s->buf_ptr = s->buf;
|
|
s->bit_left=32;
|
|
s->bit_buf=0;
|
|
#endif
|
|
}
|
|
|
|
/* return the number of bits output */
|
|
INT64 get_bit_count(PutBitContext *s)
|
|
{
|
|
#ifdef ALT_BITSTREAM_WRITER
|
|
return s->data_out_size * 8 + s->index;
|
|
#else
|
|
return (s->buf_ptr - s->buf + s->data_out_size) * 8 + 32 - (INT64)s->bit_left;
|
|
#endif
|
|
}
|
|
|
|
void align_put_bits(PutBitContext *s)
|
|
{
|
|
#ifdef ALT_BITSTREAM_WRITER
|
|
put_bits(s,( - s->index) & 7,0);
|
|
#else
|
|
put_bits(s,s->bit_left & 7,0);
|
|
#endif
|
|
}
|
|
|
|
/* pad the end of the output stream with zeros */
|
|
void flush_put_bits(PutBitContext *s)
|
|
{
|
|
#ifdef ALT_BITSTREAM_WRITER
|
|
align_put_bits(s);
|
|
#else
|
|
s->bit_buf<<= s->bit_left;
|
|
while (s->bit_left < 32) {
|
|
/* XXX: should test end of buffer */
|
|
*s->buf_ptr++=s->bit_buf >> 24;
|
|
s->bit_buf<<=8;
|
|
s->bit_left+=8;
|
|
}
|
|
s->bit_left=32;
|
|
s->bit_buf=0;
|
|
#endif
|
|
}
|
|
|
|
void put_string(PutBitContext * pbc, char *s)
|
|
{
|
|
while(*s){
|
|
put_bits(pbc, 8, *s);
|
|
s++;
|
|
}
|
|
put_bits(pbc, 8, 0);
|
|
}
|
|
|
|
/* bit input functions */
|
|
|
|
void init_get_bits(GetBitContext *s,
|
|
UINT8 *buffer, int buffer_size)
|
|
{
|
|
s->buffer= buffer;
|
|
s->size= buffer_size;
|
|
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
|
|
{
|
|
OPEN_READER(re, s)
|
|
UPDATE_CACHE(re, s)
|
|
// UPDATE_CACHE(re, s)
|
|
CLOSE_READER(re, s)
|
|
}
|
|
#ifdef A32_BITSTREAM_READER
|
|
s->cache1 = 0;
|
|
#endif
|
|
}
|
|
|
|
void align_get_bits(GetBitContext *s)
|
|
{
|
|
int n= (-get_bits_count(s)) & 7;
|
|
if(n) skip_bits(s, n);
|
|
}
|
|
|
|
int check_marker(GetBitContext *s, const char *msg)
|
|
{
|
|
int bit= get_bits1(s);
|
|
if(!bit) printf("Marker bit missing %s\n", msg);
|
|
|
|
return bit;
|
|
}
|
|
|
|
/* VLC decoding */
|
|
|
|
//#define DEBUG_VLC
|
|
|
|
#define GET_DATA(v, table, i, wrap, size) \
|
|
{\
|
|
const UINT8 *ptr = (UINT8 *)table + i * wrap;\
|
|
switch(size) {\
|
|
case 1:\
|
|
v = *(UINT8 *)ptr;\
|
|
break;\
|
|
case 2:\
|
|
v = *(UINT16 *)ptr;\
|
|
break;\
|
|
default:\
|
|
v = *(UINT32 *)ptr;\
|
|
break;\
|
|
}\
|
|
}
|
|
|
|
|
|
static int alloc_table(VLC *vlc, int size)
|
|
{
|
|
int index;
|
|
index = vlc->table_size;
|
|
vlc->table_size += size;
|
|
if (vlc->table_size > vlc->table_allocated) {
|
|
vlc->table_allocated += (1 << vlc->bits);
|
|
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,
|
|
int nb_codes,
|
|
const void *bits, int bits_wrap, int bits_size,
|
|
const void *codes, int codes_wrap, int codes_size,
|
|
UINT32 code_prefix, int n_prefix)
|
|
{
|
|
int i, j, k, n, table_size, table_index, nb, n1, index;
|
|
UINT32 code;
|
|
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",
|
|
table_index, table_size, code_prefix, n_prefix);
|
|
#endif
|
|
if (table_index < 0)
|
|
return -1;
|
|
table = &vlc->table[table_index];
|
|
|
|
for(i=0;i<table_size;i++) {
|
|
table[i][1] = 0; //bits
|
|
table[i][0] = -1; //codes
|
|
}
|
|
|
|
/* first pass: map codes and compute auxillary table sizes */
|
|
for(i=0;i<nb_codes;i++) {
|
|
GET_DATA(n, bits, i, bits_wrap, bits_size);
|
|
GET_DATA(code, codes, i, codes_wrap, codes_size);
|
|
/* we accept tables with holes */
|
|
if (n <= 0)
|
|
continue;
|
|
#if defined(DEBUG_VLC) && 0
|
|
printf("i=%d n=%d code=0x%x\n", i, n, code);
|
|
#endif
|
|
/* if code matches the prefix, it is in the table */
|
|
n -= n_prefix;
|
|
if (n > 0 && (code >> n) == code_prefix) {
|
|
if (n <= table_nb_bits) {
|
|
/* no need to add another table */
|
|
j = (code << (table_nb_bits - n)) & (table_size - 1);
|
|
nb = 1 << (table_nb_bits - n);
|
|
for(k=0;k<nb;k++) {
|
|
#ifdef DEBUG_VLC
|
|
printf("%4x: code=%d n=%d\n",
|
|
j, i, n);
|
|
#endif
|
|
if (table[j][1] /*bits*/ != 0) {
|
|
fprintf(stderr, "incorrect codes\n");
|
|
exit(1);
|
|
}
|
|
table[j][1] = n; //bits
|
|
table[j][0] = i; //code
|
|
j++;
|
|
}
|
|
} else {
|
|
n -= table_nb_bits;
|
|
j = (code >> n) & ((1 << table_nb_bits) - 1);
|
|
#ifdef DEBUG_VLC
|
|
printf("%4x: n=%d (subtable)\n",
|
|
j, n);
|
|
#endif
|
|
/* compute table size */
|
|
n1 = -table[j][1]; //bits
|
|
if (n > n1)
|
|
n1 = n;
|
|
table[j][1] = -n1; //bits
|
|
}
|
|
}
|
|
}
|
|
|
|
/* second pass : fill auxillary tables recursively */
|
|
for(i=0;i<table_size;i++) {
|
|
n = table[i][1]; //bits
|
|
if (n < 0) {
|
|
n = -n;
|
|
if (n > table_nb_bits) {
|
|
n = table_nb_bits;
|
|
table[i][1] = -n; //bits
|
|
}
|
|
index = build_table(vlc, n, nb_codes,
|
|
bits, bits_wrap, bits_size,
|
|
codes, codes_wrap, codes_size,
|
|
(code_prefix << table_nb_bits) | i,
|
|
n_prefix + table_nb_bits);
|
|
if (index < 0)
|
|
return -1;
|
|
/* note: realloc has been done, so reload tables */
|
|
table = &vlc->table[table_index];
|
|
table[i][0] = index; //code
|
|
}
|
|
}
|
|
return table_index;
|
|
}
|
|
|
|
|
|
/* Build VLC decoding tables suitable for use with get_vlc().
|
|
|
|
'nb_bits' set thee decoding table size (2^nb_bits) entries. The
|
|
bigger it is, the faster is the decoding. But it should not be too
|
|
big to save memory and L1 cache. '9' is a good compromise.
|
|
|
|
'nb_codes' : number of vlcs codes
|
|
|
|
'bits' : table which gives the size (in bits) of each vlc code.
|
|
|
|
'codes' : table which gives the bit pattern of of each vlc code.
|
|
|
|
'xxx_wrap' : give the number of bytes between each entry of the
|
|
'bits' or 'codes' tables.
|
|
|
|
'xxx_size' : gives the number of bytes of each entry of the 'bits'
|
|
or 'codes' tables.
|
|
|
|
'wrap' and 'size' allows to use any memory configuration and types
|
|
(byte/word/long) to store the 'bits' and 'codes' tables.
|
|
*/
|
|
int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
|
|
const void *bits, int bits_wrap, int bits_size,
|
|
const void *codes, int codes_wrap, int codes_size)
|
|
{
|
|
vlc->bits = nb_bits;
|
|
vlc->table = NULL;
|
|
vlc->table_allocated = 0;
|
|
vlc->table_size = 0;
|
|
#ifdef DEBUG_VLC
|
|
printf("build table nb_codes=%d\n", nb_codes);
|
|
#endif
|
|
|
|
if (build_table(vlc, nb_bits, nb_codes,
|
|
bits, bits_wrap, bits_size,
|
|
codes, codes_wrap, codes_size,
|
|
0, 0) < 0) {
|
|
av_free(vlc->table);
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
void free_vlc(VLC *vlc)
|
|
{
|
|
av_free(vlc->table);
|
|
}
|
|
|
|
int ff_gcd(int a, int b){
|
|
if(b) return ff_gcd(b, a%b);
|
|
else return a;
|
|
}
|
|
|
|
void ff_float2fraction(int *nom_arg, int *denom_arg, double f, int max){
|
|
double best_diff=1E10, diff;
|
|
int best_denom=1, best_nom=1;
|
|
int nom, denom, gcd;
|
|
|
|
//brute force here, perhaps we should try continued fractions if we need large max ...
|
|
for(denom=1; denom<=max; denom++){
|
|
nom= (int)(f*denom + 0.5);
|
|
if(nom<=0 || nom>max) continue;
|
|
|
|
diff= ABS( f - (double)nom / (double)denom );
|
|
if(diff < best_diff){
|
|
best_diff= diff;
|
|
best_nom= nom;
|
|
best_denom= denom;
|
|
}
|
|
}
|
|
|
|
gcd= ff_gcd(best_nom, best_denom);
|
|
best_nom /= gcd;
|
|
best_denom /= gcd;
|
|
|
|
*nom_arg= best_nom;
|
|
*denom_arg= best_denom;
|
|
}
|