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FFmpeg/libavcodec/mpeg_er.c
Andreas Rheinhardt 7b539ca3e6 avcodec/mpeg_er: Simplify disabling IDCT
The error resilience code does not make up block coefficients
and therefore zeroes them in order to disable the IDCT.
But this can be done in a simpler manner, namely by setting
block_last_index to a negative value. Doing so also has
the advantage that the dct_unquantize functions are never even
called for those codecs that do not use ff_mpv_reconstruct_mb()
for ordinary decoding (namely RV-30/40 and the VC-1 family).

This approach would not work for intra macroblocks (there is always
at least one coefficient for them and therefore there is no check
for block_last_index for them), but this does not happen at all.
Add an assert for this.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2024-06-20 18:58:39 +02:00

137 lines
4.0 KiB
C

/*
* 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
*/
#include "libavutil/avassert.h"
#include "libavutil/mem.h"
#include "error_resilience.h"
#include "mpegvideo.h"
#include "mpegvideodec.h"
#include "mpeg_er.h"
static void set_erpic(ERPicture *dst, const MPVPicture *src)
{
int i;
memset(dst, 0, sizeof(*dst));
if (!src) {
dst->f = NULL;
dst->tf = NULL;
return;
}
dst->f = src->f;
dst->progress = &src->progress;
for (i = 0; i < 2; i++) {
dst->motion_val[i] = src->motion_val[i];
dst->ref_index[i] = src->ref_index[i];
}
dst->mb_type = src->mb_type;
dst->field_picture = src->field_picture;
}
void ff_mpeg_er_frame_start(MpegEncContext *s)
{
ERContext *er = &s->er;
set_erpic(&er->cur_pic, s->cur_pic.ptr);
set_erpic(&er->next_pic, s->next_pic.ptr);
set_erpic(&er->last_pic, s->last_pic.ptr);
er->pp_time = s->pp_time;
er->pb_time = s->pb_time;
er->quarter_sample = s->quarter_sample;
er->partitioned_frame = s->partitioned_frame;
ff_er_frame_start(er);
}
static void mpeg_er_decode_mb(void *opaque, int ref, int mv_dir, int mv_type,
int (*mv)[2][4][2], int mb_x, int mb_y,
int mb_intra, int mb_skipped)
{
MpegEncContext *s = opaque;
av_assert1(!mb_intra);
s->mv_dir = mv_dir;
s->mv_type = mv_type;
s->mb_intra = mb_intra;
s->mb_skipped = mb_skipped;
s->mb_x = mb_x;
s->mb_y = mb_y;
s->mcsel = 0;
memcpy(s->mv, mv, sizeof(*mv));
// The following disables the IDCT.
for (size_t i = 0; i < FF_ARRAY_ELEMS(s->block_last_index); i++)
s->block_last_index[i] = -1;
s->dest[0] = s->cur_pic.data[0] +
s->mb_y * 16 * s->linesize +
s->mb_x * 16;
s->dest[1] = s->cur_pic.data[1] +
s->mb_y * (16 >> s->chroma_y_shift) * s->uvlinesize +
s->mb_x * (16 >> s->chroma_x_shift);
s->dest[2] = s->cur_pic.data[2] +
s->mb_y * (16 >> s->chroma_y_shift) * s->uvlinesize +
s->mb_x * (16 >> s->chroma_x_shift);
if (ref)
av_log(s->avctx, AV_LOG_DEBUG,
"Interlaced error concealment is not fully implemented\n");
ff_mpv_reconstruct_mb(s, s->block);
}
int ff_mpeg_er_init(MpegEncContext *s)
{
ERContext *er = &s->er;
int mb_array_size = s->mb_height * s->mb_stride;
int i;
er->avctx = s->avctx;
er->mb_index2xy = s->mb_index2xy;
er->mb_num = s->mb_num;
er->mb_width = s->mb_width;
er->mb_height = s->mb_height;
er->mb_stride = s->mb_stride;
er->b8_stride = s->b8_stride;
er->er_temp_buffer = av_malloc(s->mb_height * s->mb_stride * (4*sizeof(int) + 1));
er->error_status_table = av_mallocz(mb_array_size);
if (!er->er_temp_buffer || !er->error_status_table)
goto fail;
er->mbskip_table = s->mbskip_table;
er->mbintra_table = s->mbintra_table;
for (i = 0; i < FF_ARRAY_ELEMS(s->dc_val); i++)
er->dc_val[i] = s->dc_val[i];
er->decode_mb = mpeg_er_decode_mb;
er->opaque = s;
return 0;
fail:
av_freep(&er->er_temp_buffer);
av_freep(&er->error_status_table);
return AVERROR(ENOMEM);
}