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FFmpeg/libavcodec/mdec.c
Ronald S. Bultje e639d09199 mdec: stop preferring the simple IDCT. 
This was added in e3e3c82555, probably
as a workaround for the fact that the quant table was not permutated
and the IDCT coefficients are, meaning that you'd only get correct
reconstruction if the IDCT permutation was an identity matrix, which
happens to be the case when you use the simple IDCT. The quant table
permutation bug was fixed in 42dd1434bf,
meaning this workaround is no longer necessary.

In practical terms, before 42dd1434bf,
the PSNR between decodes of the fate-mdec using simple (C) or simplemmx
IDCTs was 35. After 42dd1434bf, it's 90.
2017-06-21 09:01:32 -04:00

276 lines
8.5 KiB
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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 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 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 "blockdsp.h"
#include "bswapdsp.h"
#include "idctdsp.h"
#include "mpeg12.h"
#include "thread.h"
typedef struct MDECContext {
AVCodecContext *avctx;
BlockDSPContext bdsp;
BswapDSPContext bbdsp;
IDCTDSPContext idsp;
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];
DECLARE_ALIGNED(16, uint16_t, quant_matrix)[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 = a->quant_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] * (1 << 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;
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;
}
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;
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;
}
j = scantable[i];
if (level < 0) {
level = -level;
level = (level * (unsigned)qscale * quant_matrix[j]) >> 3;
level = (level - 1) | 1;
level = -level;
} else {
level = (level * (unsigned)qscale * quant_matrix[j]) >> 3;
level = (level - 1) | 1;
}
}
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;
static const int block_index[6] = { 5, 4, 0, 1, 2, 3 };
a->bdsp.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->idsp.idct_put(dest_y, linesize, block[0]);
a->idsp.idct_put(dest_y + 8, linesize, block[1]);
a->idsp.idct_put(dest_y + 8 * linesize, linesize, block[2]);
a->idsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);
if (!(a->avctx->flags & AV_CODEC_FLAG_GRAY)) {
a->idsp.idct_put(dest_cb, frame->linesize[1], block[4]);
a->idsp.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 ret;
if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
return ret;
frame.f->pict_type = AV_PICTURE_TYPE_I;
frame.f->key_frame = 1;
av_fast_padded_malloc(&a->bitstream_buffer, &a->bitstream_buffer_size, buf_size);
if (!a->bitstream_buffer)
return AVERROR(ENOMEM);
a->bbdsp.bswap16_buf((uint16_t *)a->bitstream_buffer, (uint16_t *)buf, (buf_size + 1) / 2);
if ((ret = init_get_bits8(&a->gb, a->bitstream_buffer, buf_size)) < 0)
return ret;
/* 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;
int i;
a->mb_width = (avctx->coded_width + 15) / 16;
a->mb_height = (avctx->coded_height + 15) / 16;
a->avctx = avctx;
ff_blockdsp_init(&a->bdsp, avctx);
ff_bswapdsp_init(&a->bbdsp);
ff_idctdsp_init(&a->idsp, avctx);
ff_mpeg12_init_vlcs();
ff_init_scantable(a->idsp.idct_permutation, &a->scantable,
ff_zigzag_direct);
avctx->pix_fmt = AV_PIX_FMT_YUVJ420P;
avctx->color_range = AVCOL_RANGE_JPEG;
/* init q matrix */
for (i = 0; i < 64; i++) {
int j = a->idsp.idct_permutation[i];
a->quant_matrix[j] = ff_mpeg1_default_intra_matrix[i];
}
return 0;
}
#if HAVE_THREADS
static av_cold int decode_init_thread_copy(AVCodecContext *avctx)
{
MDECContext * const a = avctx->priv_data;
a->avctx = avctx;
return 0;
}
#endif
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",
.long_name = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_MDEC,
.priv_data_size = sizeof(MDECContext),
.init = decode_init,
.close = decode_end,
.decode = decode_frame,
.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
.init_thread_copy = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy)
};
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