mirror of https://git.ffmpeg.org/ffmpeg.git
239 lines
7.5 KiB
C
239 lines
7.5 KiB
C
/*
|
|
* MPEG-1/2 decoder
|
|
* Copyright (c) 2000, 2001 Fabrice Bellard
|
|
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
|
|
*
|
|
* This file is part of Libav.
|
|
*
|
|
* Libav 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 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* Libav 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 Libav; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* MPEG-1/2 decoder
|
|
*/
|
|
|
|
#include "libavutil/attributes.h"
|
|
#include "internal.h"
|
|
#include "avcodec.h"
|
|
#include "dsputil.h"
|
|
#include "mpegvideo.h"
|
|
#include "error_resilience.h"
|
|
#include "mpeg12.h"
|
|
#include "mpeg12data.h"
|
|
#include "bytestream.h"
|
|
#include "thread.h"
|
|
|
|
uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
|
|
|
|
static const uint8_t table_mb_ptype[7][2] = {
|
|
{ 3, 5 }, // 0x01 MB_INTRA
|
|
{ 1, 2 }, // 0x02 MB_PAT
|
|
{ 1, 3 }, // 0x08 MB_FOR
|
|
{ 1, 1 }, // 0x0A MB_FOR|MB_PAT
|
|
{ 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
|
|
{ 1, 5 }, // 0x12 MB_QUANT|MB_PAT
|
|
{ 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
|
|
};
|
|
|
|
static const uint8_t table_mb_btype[11][2] = {
|
|
{ 3, 5 }, // 0x01 MB_INTRA
|
|
{ 2, 3 }, // 0x04 MB_BACK
|
|
{ 3, 3 }, // 0x06 MB_BACK|MB_PAT
|
|
{ 2, 4 }, // 0x08 MB_FOR
|
|
{ 3, 4 }, // 0x0A MB_FOR|MB_PAT
|
|
{ 2, 2 }, // 0x0C MB_FOR|MB_BACK
|
|
{ 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT
|
|
{ 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
|
|
{ 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT
|
|
{ 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
|
|
{ 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
|
|
};
|
|
|
|
#define INIT_2D_VLC_RL(rl, static_size)\
|
|
{\
|
|
static RL_VLC_ELEM rl_vlc_table[static_size];\
|
|
INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\
|
|
&rl.table_vlc[0][1], 4, 2,\
|
|
&rl.table_vlc[0][0], 4, 2, static_size);\
|
|
\
|
|
rl.rl_vlc[0] = rl_vlc_table;\
|
|
init_2d_vlc_rl(&rl);\
|
|
}
|
|
|
|
static av_cold void init_2d_vlc_rl(RLTable *rl)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < rl->vlc.table_size; i++) {
|
|
int code = rl->vlc.table[i][0];
|
|
int len = rl->vlc.table[i][1];
|
|
int level, run;
|
|
|
|
if (len == 0) { // illegal code
|
|
run = 65;
|
|
level = MAX_LEVEL;
|
|
} else if (len<0) { //more bits needed
|
|
run = 0;
|
|
level = code;
|
|
} else {
|
|
if (code == rl->n) { //esc
|
|
run = 65;
|
|
level = 0;
|
|
} else if (code == rl->n+1) { //eob
|
|
run = 0;
|
|
level = 127;
|
|
} else {
|
|
run = rl->table_run [code] + 1;
|
|
level = rl->table_level[code];
|
|
}
|
|
}
|
|
rl->rl_vlc[0][i].len = len;
|
|
rl->rl_vlc[0][i].level = level;
|
|
rl->rl_vlc[0][i].run = run;
|
|
}
|
|
}
|
|
|
|
av_cold void ff_mpeg12_common_init(MpegEncContext *s)
|
|
{
|
|
|
|
s->y_dc_scale_table =
|
|
s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
|
|
|
|
}
|
|
|
|
void ff_mpeg1_clean_buffers(MpegEncContext *s)
|
|
{
|
|
s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
|
|
s->last_dc[1] = s->last_dc[0];
|
|
s->last_dc[2] = s->last_dc[0];
|
|
memset(s->last_mv, 0, sizeof(s->last_mv));
|
|
}
|
|
|
|
|
|
/******************************************/
|
|
/* decoding */
|
|
|
|
VLC ff_mv_vlc;
|
|
|
|
VLC ff_dc_lum_vlc;
|
|
VLC ff_dc_chroma_vlc;
|
|
|
|
VLC ff_mbincr_vlc;
|
|
VLC ff_mb_ptype_vlc;
|
|
VLC ff_mb_btype_vlc;
|
|
VLC ff_mb_pat_vlc;
|
|
|
|
av_cold void ff_mpeg12_init_vlcs(void)
|
|
{
|
|
static int done = 0;
|
|
|
|
if (!done) {
|
|
done = 1;
|
|
|
|
INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
|
|
ff_mpeg12_vlc_dc_lum_bits, 1, 1,
|
|
ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
|
|
INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
|
|
ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
|
|
ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
|
|
INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
|
|
&ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
|
|
&ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518);
|
|
INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
|
|
&ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
|
|
&ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
|
|
INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
|
|
&ff_mpeg12_mbPatTable[0][1], 2, 1,
|
|
&ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
|
|
|
|
INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
|
|
&table_mb_ptype[0][1], 2, 1,
|
|
&table_mb_ptype[0][0], 2, 1, 64);
|
|
INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
|
|
&table_mb_btype[0][1], 2, 1,
|
|
&table_mb_btype[0][0], 2, 1, 64);
|
|
ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
|
|
ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);
|
|
|
|
INIT_2D_VLC_RL(ff_rl_mpeg1, 680);
|
|
INIT_2D_VLC_RL(ff_rl_mpeg2, 674);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Find the end of the current frame in the bitstream.
|
|
* @return the position of the first byte of the next frame, or -1
|
|
*/
|
|
int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
|
|
{
|
|
int i;
|
|
uint32_t state = pc->state;
|
|
|
|
/* EOF considered as end of frame */
|
|
if (buf_size == 0)
|
|
return 0;
|
|
|
|
/*
|
|
0 frame start -> 1/4
|
|
1 first_SEQEXT -> 0/2
|
|
2 first field start -> 3/0
|
|
3 second_SEQEXT -> 2/0
|
|
4 searching end
|
|
*/
|
|
|
|
for (i = 0; i < buf_size; i++) {
|
|
assert(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
|
|
if (pc->frame_start_found & 1) {
|
|
if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
|
|
pc->frame_start_found--;
|
|
else if (state == EXT_START_CODE + 2) {
|
|
if ((buf[i] & 3) == 3)
|
|
pc->frame_start_found = 0;
|
|
else
|
|
pc->frame_start_found = (pc->frame_start_found + 1) & 3;
|
|
}
|
|
state++;
|
|
} else {
|
|
i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
|
|
if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
|
|
i++;
|
|
pc->frame_start_found = 4;
|
|
}
|
|
if (state == SEQ_END_CODE) {
|
|
pc->frame_start_found = 0;
|
|
pc->state=-1;
|
|
return i+1;
|
|
}
|
|
if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
|
|
pc->frame_start_found = 0;
|
|
if (pc->frame_start_found < 4 && state == EXT_START_CODE)
|
|
pc->frame_start_found++;
|
|
if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
|
|
if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
|
|
pc->frame_start_found = 0;
|
|
pc->state = -1;
|
|
return i - 3;
|
|
}
|
|
}
|
|
if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
|
|
ff_fetch_timestamp(s, i - 3, 1);
|
|
}
|
|
}
|
|
}
|
|
pc->state = state;
|
|
return END_NOT_FOUND;
|
|
}
|