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ffmpeg/libavcodec/mdec.c

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/*
* Sony PlayStation MDEC (Motion DECoder)
* Copyright (c) 2003 Michael Niedermayer
*
* based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
*
* 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
* Sony PlayStation MDEC (Motion DECoder)
* This is very similar to intra-only MPEG-1.
*/
#include "avcodec.h"
#include "mpegvideo.h"
#include "mpeg12.h"
#include "thread.h"
typedef struct MDECContext {
AVCodecContext *avctx;
DSPContext dsp;
ThreadFrame frame;
GetBitContext gb;
ScanTable scantable;
int version;
int qscale;
int last_dc[3];
int mb_width;
int mb_height;
int mb_x, mb_y;
DECLARE_ALIGNED(16, int16_t, block)[6][64];
uint8_t *bitstream_buffer;
unsigned int bitstream_buffer_size;
int block_last_index[6];
} MDECContext;
//very similar to MPEG-1
static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)
{
int level, diff, i, j, run;
int component;
RLTable *rl = &ff_rl_mpeg1;
uint8_t * const scantable = a->scantable.permutated;
const uint16_t *quant_matrix = ff_mpeg1_default_intra_matrix;
const int qscale = a->qscale;
/* DC coefficient */
if (a->version == 2) {
block[0] = 2 * get_sbits(&a->gb, 10) + 1024;
} else {
component = (n <= 3 ? 0 : n - 4 + 1);
diff = decode_dc(&a->gb, component);
if (diff >= 0xffff)
return AVERROR_INVALIDDATA;
a->last_dc[component] += diff;
block[0] = a->last_dc[component] << 3;
}
i = 0;
{
OPEN_READER(re, &a->gb);
/* now quantify & encode AC coefficients */
for (;;) {
UPDATE_CACHE(re, &a->gb);
GET_RL_VLC(level, run, re, &a->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 * qscale * quant_matrix[j]) >> 3;
level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
LAST_SKIP_BITS(re, &a->gb, 1);
} else {
/* escape */
run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
UPDATE_CACHE(re, &a->gb);
level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
i += run;
j = scantable[i];
if (level < 0) {
level = -level;
level = (level * qscale * quant_matrix[j]) >> 3;
level = (level - 1) | 1;
level = -level;
} else {
level = (level * qscale * quant_matrix[j]) >> 3;
level = (level - 1) | 1;
}
}
if (i > 63) {
av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
return AVERROR_INVALIDDATA;
}
block[j] = level;
}
CLOSE_READER(re, &a->gb);
}
a->block_last_index[n] = i;
return 0;
}
static inline int decode_mb(MDECContext *a, int16_t block[6][64])
{
int i, ret;
const int block_index[6] = { 5, 4, 0, 1, 2, 3 };
a->dsp.clear_blocks(block[0]);
for (i = 0; i < 6; i++) {
if ((ret = mdec_decode_block_intra(a, block[block_index[i]],
block_index[i])) < 0)
return ret;
if (get_bits_left(&a->gb) < 0)
return AVERROR_INVALIDDATA;
}
return 0;
}
static inline void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)
{
int16_t (*block)[64] = a->block;
int linesize = frame->linesize[0];
uint8_t *dest_y = frame->data[0] + (mb_y * 16* linesize ) + mb_x * 16;
uint8_t *dest_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;
uint8_t *dest_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;
a->dsp.idct_put(dest_y, linesize, block[0]);
a->dsp.idct_put(dest_y + 8, linesize, block[1]);
a->dsp.idct_put(dest_y + 8 * linesize, linesize, block[2]);
a->dsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);
if (!(a->avctx->flags & CODEC_FLAG_GRAY)) {
a->dsp.idct_put(dest_cb, frame->linesize[1], block[4]);
a->dsp.idct_put(dest_cr, frame->linesize[2], block[5]);
}
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
MDECContext * const a = avctx->priv_data;
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
ThreadFrame frame = { .f = data };
int i, ret;
if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
frame.f->pict_type = AV_PICTURE_TYPE_I;
frame.f->key_frame = 1;
av_fast_malloc(&a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
if (!a->bitstream_buffer)
return AVERROR(ENOMEM);
for (i = 0; i < buf_size; i += 2) {
a->bitstream_buffer[i] = buf[i + 1];
a->bitstream_buffer[i + 1] = buf[i];
}
init_get_bits(&a->gb, a->bitstream_buffer, buf_size * 8);
/* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
skip_bits(&a->gb, 32);
a->qscale = get_bits(&a->gb, 16);
a->version = get_bits(&a->gb, 16);
a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;
for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {
for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {
if ((ret = decode_mb(a, a->block)) < 0)
return ret;
idct_put(a, frame.f, a->mb_x, a->mb_y);
}
}
*got_frame = 1;
return (get_bits_count(&a->gb) + 31) / 32 * 4;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
MDECContext * const a = avctx->priv_data;
a->mb_width = (avctx->coded_width + 15) / 16;
a->mb_height = (avctx->coded_height + 15) / 16;
a->avctx = avctx;
ff_dsputil_init(&a->dsp, avctx);
ff_mpeg12_init_vlcs();
ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
if (avctx->idct_algo == FF_IDCT_AUTO)
avctx->idct_algo = FF_IDCT_SIMPLE;
avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
return 0;
}
static av_cold int decode_init_thread_copy(AVCodecContext *avctx)
{
MDECContext * const a = avctx->priv_data;
a->avctx = avctx;
return 0;
}
static av_cold int decode_end(AVCodecContext *avctx)
{
MDECContext * const a = avctx->priv_data;
av_freep(&a->bitstream_buffer);
a->bitstream_buffer_size = 0;
return 0;
}
AVCodec ff_mdec_decoder = {
.name = "mdec",
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_MDEC,
.priv_data_size = sizeof(MDECContext),
.init = decode_init,
.close = decode_end,
.decode = decode_frame,
.capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
.long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
.init_thread_copy = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy)
};
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