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ffmpeg.wasm-core
Commit 901ee2be authored by Roman Shaposhnik's avatar Roman Shaposhnik
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* some significant clean-up of the dv_decode_ac (it looks real 

     simple now, take a look for yourself).

   * additional optimizations of the decoder. It runs at 55fps now
     on my desktop and it used to be ~45fps.

Originally committed as revision 2926 to svn://svn.ffmpeg.org/ffmpeg/trunk
parent 7906085f
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Showing with 67 additions and 95 deletions
libavcodec/dv.c
View file @ 901ee2be
/*
* DV decoder
* Copyright (c) 2002 Fabrice Bellard.
* Copyright (c) 2004 Roman Shaposhnik.
*
* DV encoder
* Copyright (c) 2003 Roman Shaposhnik.
......@@ -39,7 +40,7 @@ typedef struct DVVideoContext {
uint8_t *buf;
uint8_t dv_zigzag[2][64];
uint8_t dv_idct_shift[2][22][64];
uint8_t dv_idct_shift[2][2][22][64];
void (*get_pixels)(DCTELEM *block, const uint8_t *pixels, int line_size);
void (*fdct[2])(DCTELEM *block);
......@@ -77,15 +78,17 @@ static void dv_build_unquantize_tables(DVVideoContext *s, uint8_t* perm)
for(i = 1; i < 64; i++) {
/* 88 table */
j = perm[i];
s->dv_idct_shift[0][q][j] =
s->dv_idct_shift[0][0][q][j] =
dv_quant_shifts[q][dv_88_areas[i]] + 1;
s->dv_idct_shift[1][0][q][j] = s->dv_idct_shift[0][0][q][j] + 1;
}
/* 248DCT */
for(i = 1; i < 64; i++) {
/* 248 table */
s->dv_idct_shift[1][q][i] =
s->dv_idct_shift[0][1][q][i] =
dv_quant_shifts[q][dv_248_areas[i]] + 1;
s->dv_idct_shift[1][1][q][i] = s->dv_idct_shift[0][1][q][i] + 1;
}
}
}
......@@ -98,8 +101,11 @@ static int dvvideo_init(AVCodecContext *avctx)
int i, j;
if (!done) {
int i;
VLC dv_vlc;
uint16_t new_dv_vlc_bits[NB_DV_VLC*2];
uint8_t new_dv_vlc_len[NB_DV_VLC*2];
uint8_t new_dv_vlc_run[NB_DV_VLC*2];
int16_t new_dv_vlc_level[NB_DV_VLC*2];
done = 1;
......@@ -107,6 +113,7 @@ static int dvvideo_init(AVCodecContext *avctx)
if (!dv_vlc_map)
return -ENOMEM;
/* dv_anchor lets each thread know its Id */
dv_anchor = av_malloc(12*27*sizeof(void*));
if (!dv_anchor) {
av_free(dv_vlc_map);
......@@ -115,10 +122,29 @@ static int dvvideo_init(AVCodecContext *avctx)
for (i=0; i<12*27; i++)
dv_anchor[i] = (void*)(size_t)i;
/* it's faster to include sign bit in a generic VLC parsing scheme */
for (i=0, j=0; i<NB_DV_VLC; i++, j++) {
new_dv_vlc_bits[j] = dv_vlc_bits[i];
new_dv_vlc_len[j] = dv_vlc_len[i];
new_dv_vlc_run[j] = dv_vlc_run[i];
new_dv_vlc_level[j] = dv_vlc_level[i];
if (dv_vlc_level[i]) {
new_dv_vlc_bits[j] <<= 1;
new_dv_vlc_len[j]++;
j++;
new_dv_vlc_bits[j] = (dv_vlc_bits[i] << 1) | 1;
new_dv_vlc_len[j] = dv_vlc_len[i] + 1;
new_dv_vlc_run[j] = dv_vlc_run[i];
new_dv_vlc_level[j] = -dv_vlc_level[i];
}
}
/* NOTE: as a trick, we use the fact the no codes are unused
to accelerate the parsing of partial codes */
init_vlc(&dv_vlc, TEX_VLC_BITS, NB_DV_VLC,
dv_vlc_len, 1, 1, dv_vlc_bits, 2, 2);
init_vlc(&dv_vlc, TEX_VLC_BITS, j,
new_dv_vlc_len, 1, 1, new_dv_vlc_bits, 2, 2);
dv_rl_vlc = av_malloc(dv_vlc.table_size * sizeof(RL_VLC_ELEM));
if (!dv_rl_vlc) {
......@@ -135,8 +161,8 @@ static int dvvideo_init(AVCodecContext *avctx)
run= 0;
level= code;
} else {
run= dv_vlc_run[code] + 1;
level= dv_vlc_level[code];
run= new_dv_vlc_run[code] + 1;
level= new_dv_vlc_level[code];
}
dv_rl_vlc[i].len = len;
dv_rl_vlc[i].level = level;
......@@ -216,6 +242,7 @@ static int dvvideo_end(AVCodecContext *avctx)
}
// #define VLC_DEBUG
// #define printf(...) av_log(NULL, AV_LOG_ERROR, __VA_ARGS__)
typedef struct BlockInfo {
const uint8_t *shift_table;
......@@ -259,115 +286,61 @@ static inline int put_bits_left(PutBitContext* s)
static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block)
{
int last_index = get_bits_size(gb);
int last_re_index;
int shift_offset = mb->shift_offset;
const uint8_t *scan_table = mb->scan_table;
const uint8_t *shift_table = mb->shift_table;
int pos = mb->pos;
int level, pos1, run;
int partial_bit_count;
int sign = 0;
#ifndef ALT_BITSTREAM_READER //FIXME
int re_index=0;
int re1_index=0;
#endif
OPEN_READER(re, gb);
int partial_bit_count = mb->partial_bit_count;
int level, pos1, run, vlc_len, index;
#ifdef VLC_DEBUG
printf("start\n");
#endif
OPEN_READER(re, gb);
UPDATE_CACHE(re, gb);
/* if we must parse a partial vlc, we do it here */
partial_bit_count = mb->partial_bit_count;
if (partial_bit_count > 0) {
uint8_t buf[4];
uint32_t v;
int l;
GetBitContext gb1;
/* build the dummy bit buffer */
l = 16 - partial_bit_count;
UPDATE_CACHE(re, gb);
#ifdef VLC_DEBUG
printf("show=%04x\n", SHOW_UBITS(re, gb, 16));
#endif
v = (mb->partial_bit_buffer << l) | SHOW_UBITS(re, gb, l);
buf[0] = v >> 8;
buf[1] = v;
#ifdef VLC_DEBUG
printf("v=%04x cnt=%d %04x\n",
v, partial_bit_count, (mb->partial_bit_buffer << l));
#endif
/* try to read the codeword */
init_get_bits(&gb1, buf, 4*8);
{
OPEN_READER(re1, &gb1);
UPDATE_CACHE(re1, &gb1);
GET_RL_VLC(level, run, re1, &gb1, dv_rl_vlc,
TEX_VLC_BITS, 2);
l = re1_index;
CLOSE_READER(re1, &gb1);
}
#ifdef VLC_DEBUG
printf("****run=%d level=%d size=%d\n", run, level, l);
#endif
/* compute codeword length -- if too long, we cannot parse */
l -= partial_bit_count;
if ((re_index + l + (level != 0)) > last_index) {
mb->partial_bit_count += (last_index - re_index);
mb->partial_bit_buffer = v >> (16 - mb->partial_bit_count);
return;
}
/* skip read bits */
last_re_index = 0; /* avoid warning */
re_index += l;
/* by definition, if we can read the vlc, all partial bits
will be read (otherwise we could have read the vlc before) */
re_cache = ((unsigned)re_cache >> partial_bit_count) |
(mb->partial_bit_buffer << (sizeof(re_cache)*8 - partial_bit_count));
re_index -= partial_bit_count;
mb->partial_bit_count = 0;
UPDATE_CACHE(re, gb);
goto handle_vlc;
}
/* get the AC coefficients until last_index is reached */
for(;;) {
UPDATE_CACHE(re, gb);
#ifdef VLC_DEBUG
printf("%2d: bits=%04x index=%d\n",
pos, SHOW_UBITS(re, gb, 16), re_index);
#endif
last_re_index = re_index;
GET_RL_VLC(level, run, re, gb, dv_rl_vlc,
TEX_VLC_BITS, 2);
handle_vlc:
#ifdef VLC_DEBUG
printf("run=%d level=%d\n", run, level);
printf("%2d: bits=%04x index=%d\n", pos, SHOW_UBITS(re, gb, 16), re_index);
#endif
if (level) {
sign = SHOW_SBITS(re, gb, 1);
LAST_SKIP_BITS(re, gb, 1);
}
if (re_index > last_index) {
/* our own optimized GET_RL_VLC */
index = NEG_USR32(re_cache, TEX_VLC_BITS);
vlc_len = dv_rl_vlc[index].len;
if (vlc_len < 0) {
index = NEG_USR32((unsigned)re_cache << TEX_VLC_BITS, -vlc_len) + dv_rl_vlc[index].level;
vlc_len = TEX_VLC_BITS - vlc_len;
}
level = dv_rl_vlc[index].level;
run = dv_rl_vlc[index].run;
/* gotta check if we're still within gb boundaries */
if (re_index + vlc_len > last_index) {
/* should be < 16 bits otherwise a codeword could have been parsed */
re_index = last_re_index;
UPDATE_CACHE(re, gb);
mb->partial_bit_count = last_index - re_index;
mb->partial_bit_buffer = SHOW_UBITS(re, gb, mb->partial_bit_count);
mb->partial_bit_buffer = NEG_USR32(re_cache, mb->partial_bit_count);
re_index = last_index;
break;
}
re_index += vlc_len;
#ifdef VLC_DEBUG
printf("run=%d level=%d\n", run, level);
#endif
pos += run;
if (pos >= 64)
break;
if (level) {
level = (level ^ sign) - sign;
pos1 = scan_table[pos];
level = level << (shift_table[pos1] + shift_offset);
block[pos1] = level;
// printf("run=%d level=%d shift=%d\n", run, level, shift_table[pos1]);
block[pos1] = level << shift_table[pos1];
}
UPDATE_CACHE(re, gb);
}
CLOSE_READER(re, gb);
mb->pos = pos;
......@@ -429,8 +402,7 @@ static inline void dv_decode_video_segment(DVVideoContext *s,
mb->dct_mode = dct_mode;
mb->scan_table = s->dv_zigzag[dct_mode];
class1 = get_bits(&gb, 2);
mb->shift_offset = (class1 == 3);
mb->shift_table = s->dv_idct_shift[dct_mode]
mb->shift_table = s->dv_idct_shift[class1 == 3][dct_mode]
[quant + dv_quant_offset[class1]];
dc = dc << 2;
/* convert to unsigned because 128 is not added in the
......
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