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ffmpeg/libavcodec/eamad.c

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/*
* Electronic Arts Madcow Video Decoder
* Copyright (c) 2007-2009 Peter Ross
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Electronic Arts Madcow Video Decoder
* by Peter Ross <pross@xvid.org>
*
* Technical details here:
* http://wiki.multimedia.cx/index.php?title=Electronic_Arts_MAD
*/
#include "avcodec.h"
#include "get_bits.h"
#include "dsputil.h"
#include "aandcttab.h"
#include "mpeg12.h"
#include "mpeg12data.h"
#define EA_PREAMBLE_SIZE 8
#define MADk_TAG MKTAG('M', 'A', 'D', 'k') /* MAD i-frame */
#define MADm_TAG MKTAG('M', 'A', 'D', 'm') /* MAD p-frame */
#define MADe_TAG MKTAG('M', 'A', 'D', 'e') /* MAD lqp-frame */
typedef struct MadContext {
MpegEncContext s;
AVFrame frame;
AVFrame last_frame;
void *bitstream_buf;
unsigned int bitstream_buf_size;
DECLARE_ALIGNED(16, DCTELEM, block)[64];
} MadContext;
static void bswap16_buf(uint16_t *dst, const uint16_t *src, int count)
{
int i;
for (i=0; i<count; i++)
dst[i] = bswap_16(src[i]);
}
static av_cold int decode_init(AVCodecContext *avctx)
{
MadContext *t = avctx->priv_data;
MpegEncContext *s = &t->s;
s->avctx = avctx;
avctx->pix_fmt = PIX_FMT_YUV420P;
if (avctx->idct_algo == FF_IDCT_AUTO)
avctx->idct_algo = FF_IDCT_EA;
dsputil_init(&s->dsp, avctx);
ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct);
ff_mpeg12_init_vlcs();
return 0;
}
static inline void comp(unsigned char *dst, int dst_stride,
unsigned char *src, int src_stride, int add)
{
int j, i;
for (j=0; j<8; j++)
for (i=0; i<8; i++)
dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
}
static inline void comp_block(MadContext *t, int mb_x, int mb_y,
int j, int mv_x, int mv_y, int add)
{
MpegEncContext *s = &t->s;
if (j < 4) {
comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
t->frame.linesize[0],
t->last_frame.data[0] + (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x,
t->last_frame.linesize[0], add);
} else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
int index = j - 3;
comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
t->frame.linesize[index],
t->last_frame.data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2),
t->last_frame.linesize[index], add);
}
}
static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j)
{
MpegEncContext *s = &t->s;
if (j < 4) {
s->dsp.idct_put(
t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
t->frame.linesize[0], block);
} else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
int index = j - 3;
s->dsp.idct_put(
t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
t->frame.linesize[index], block);
}
}
static inline void decode_block_intra(MadContext * t, DCTELEM * block)
{
MpegEncContext *s = &t->s;
int level, i, j, run;
RLTable *rl = &ff_rl_mpeg1;
const uint8_t *scantable = s->intra_scantable.permutated;
int16_t *quant_matrix = s->intra_matrix;
block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
/* The RL decoder is derived from mpeg1_decode_block_intra;
Escaped level and run values a decoded differently */
i = 0;
{
OPEN_READER(re, &s->gb);
/* now quantify & encode AC coefficients */
for (;;) {
UPDATE_CACHE(re, &s->gb);
GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
if (level == 127) {
break;
} else if (level != 0) {
i += run;
j = scantable[i];
level = (level*quant_matrix[j]) >> 4;
level = (level-1)|1;
level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
LAST_SKIP_BITS(re, &s->gb, 1);
} else {
/* escape */
UPDATE_CACHE(re, &s->gb);
level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
UPDATE_CACHE(re, &s->gb);
run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
i += run;
j = scantable[i];
if (level < 0) {
level = -level;
level = (level*quant_matrix[j]) >> 4;
level = (level-1)|1;
level = -level;
} else {
level = (level*quant_matrix[j]) >> 4;
level = (level-1)|1;
}
}
if (i > 63) {
av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
return;
}
block[j] = level;
}
CLOSE_READER(re, &s->gb);
}
}
static int decode_motion(GetBitContext *gb)
{
int value = 0;
if (get_bits1(gb)) {
if (get_bits1(gb))
value = -17;
value += get_bits(gb, 4) + 1;
}
return value;
}
static void decode_mb(MadContext *t, int inter)
{
MpegEncContext *s = &t->s;
int mv_map = 0;
int mv_x, mv_y;
int j;
if (inter) {
int v = decode210(&s->gb);
if (v < 2) {
mv_map = v ? get_bits(&s->gb, 6) : 63;
mv_x = decode_motion(&s->gb);
mv_y = decode_motion(&s->gb);
} else {
mv_map = 0;
}
}
for (j=0; j<6; j++) {
if (mv_map & (1<<j)) { // mv_x and mv_y are guarded by mv_map
int add = 2*decode_motion(&s->gb);
comp_block(t, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
} else {
s->dsp.clear_block(t->block);
decode_block_intra(t, t->block);
idct_put(t, t->block, s->mb_x, s->mb_y, j);
}
}
}
static void calc_intra_matrix(MadContext *t, int qscale)
{
MpegEncContext *s = &t->s;
int i;
if (s->avctx->idct_algo == FF_IDCT_EA) {
s->intra_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
for (i=1; i<64; i++)
s->intra_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
} else {
s->intra_matrix[0] = ff_mpeg1_default_intra_matrix[0];
for (i=1; i<64; i++)
s->intra_matrix[i] = (ff_mpeg1_default_intra_matrix[i]*qscale) << 1;
}
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
const uint8_t *buf_end = buf+buf_size;
MadContext *t = avctx->priv_data;
MpegEncContext *s = &t->s;
int chunk_type;
int inter;
if (buf_size < 17) {
av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
*data_size = 0;
return -1;
}
chunk_type = AV_RL32(&buf[0]);
inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
buf += 8;
av_reduce(&avctx->time_base.num, &avctx->time_base.den,
AV_RL16(&buf[6]), 1000, 1<<30);
s->width = AV_RL16(&buf[8]);
s->height = AV_RL16(&buf[10]);
calc_intra_matrix(t, buf[13]);
buf += 16;
if (avctx->width != s->width || avctx->height != s->height) {
if (avcodec_check_dimensions(avctx, s->width, s->height) < 0)
return -1;
avcodec_set_dimensions(avctx, s->width, s->height);
if (t->frame.data[0])
avctx->release_buffer(avctx, &t->frame);
}
t->frame.reference = 1;
if (!t->frame.data[0]) {
if (avctx->get_buffer(avctx, &t->frame) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
}
av_fast_malloc(&t->bitstream_buf, &t->bitstream_buf_size, (buf_end-buf) + FF_INPUT_BUFFER_PADDING_SIZE);
if (!t->bitstream_buf)
return AVERROR(ENOMEM);
bswap16_buf(t->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
init_get_bits(&s->gb, t->bitstream_buf, 8*(buf_end-buf));
for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
decode_mb(t, inter);
*data_size = sizeof(AVFrame);
*(AVFrame*)data = t->frame;
if (chunk_type != MADe_TAG)
FFSWAP(AVFrame, t->frame, t->last_frame);
return buf_size;
}
static av_cold int decode_end(AVCodecContext *avctx)
{
MadContext *t = avctx->priv_data;
if (t->frame.data[0])
avctx->release_buffer(avctx, &t->frame);
if (t->last_frame.data[0])
avctx->release_buffer(avctx, &t->last_frame);
av_free(t->bitstream_buf);
return 0;
}
AVCodec eamad_decoder = {
"eamad",
AVMEDIA_TYPE_VIDEO,
CODEC_ID_MAD,
sizeof(MadContext),
decode_init,
NULL,
decode_end,
decode_frame,
CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
};
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