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FFmpeg/libavcodec/escape130.c
Andreas Rheinhardt 4243da4ff4 avcodec/codec_internal: Use union for FFCodec decode/encode callbacks 
This is possible, because every given FFCodec has to implement
exactly one of these. Doing so decreases sizeof(FFCodec) and
therefore decreases the size of the binary.
Notice that in case of position-independent code the decrease
is in .data.rel.ro, so that this translates to decreased
memory consumption.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-04-05 20:02:37 +02:00

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/*
* Escape 130 video decoder
* Copyright (C) 2008 Eli Friedman (eli.friedman <at> gmail.com)
*
* 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/attributes.h"
#include "libavutil/mem.h"
#define BITSTREAM_READER_LE
#include "avcodec.h"
#include "codec_internal.h"
#include "get_bits.h"
#include "internal.h"
typedef struct Escape130Context {
uint8_t *old_y_avg;
uint8_t *new_y, *old_y;
uint8_t *new_u, *old_u;
uint8_t *new_v, *old_v;
uint8_t *buf1, *buf2;
int linesize[3];
} Escape130Context;
static const uint8_t offset_table[] = { 2, 4, 10, 20 };
static const int8_t sign_table[64][4] = {
{ 0, 0, 0, 0 },
{ -1, 1, 0, 0 },
{ 1, -1, 0, 0 },
{ -1, 0, 1, 0 },
{ -1, 1, 1, 0 },
{ 0, -1, 1, 0 },
{ 1, -1, 1, 0 },
{ -1, -1, 1, 0 },
{ 1, 0, -1, 0 },
{ 0, 1, -1, 0 },
{ 1, 1, -1, 0 },
{ -1, 1, -1, 0 },
{ 1, -1, -1, 0 },
{ -1, 0, 0, 1 },
{ -1, 1, 0, 1 },
{ 0, -1, 0, 1 },
{ 0, 0, 0, 0 },
{ 1, -1, 0, 1 },
{ -1, -1, 0, 1 },
{ -1, 0, 1, 1 },
{ -1, 1, 1, 1 },
{ 0, -1, 1, 1 },
{ 1, -1, 1, 1 },
{ -1, -1, 1, 1 },
{ 0, 0, -1, 1 },
{ 1, 0, -1, 1 },
{ -1, 0, -1, 1 },
{ 0, 1, -1, 1 },
{ 1, 1, -1, 1 },
{ -1, 1, -1, 1 },
{ 0, -1, -1, 1 },
{ 1, -1, -1, 1 },
{ 0, 0, 0, 0 },
{ -1, -1, -1, 1 },
{ 1, 0, 0, -1 },
{ 0, 1, 0, -1 },
{ 1, 1, 0, -1 },
{ -1, 1, 0, -1 },
{ 1, -1, 0, -1 },
{ 0, 0, 1, -1 },
{ 1, 0, 1, -1 },
{ -1, 0, 1, -1 },
{ 0, 1, 1, -1 },
{ 1, 1, 1, -1 },
{ -1, 1, 1, -1 },
{ 0, -1, 1, -1 },
{ 1, -1, 1, -1 },
{ -1, -1, 1, -1 },
{ 0, 0, 0, 0 },
{ 1, 0, -1, -1 },
{ 0, 1, -1, -1 },
{ 1, 1, -1, -1 },
{ -1, 1, -1, -1 },
{ 1, -1, -1, -1 }
};
static const int8_t luma_adjust[] = { -4, -3, -2, -1, 1, 2, 3, 4 };
static const int8_t chroma_adjust[2][8] = {
{ 1, 1, 0, -1, -1, -1, 0, 1 },
{ 0, 1, 1, 1, 0, -1, -1, -1 }
};
static const uint8_t chroma_vals[] = {
20, 28, 36, 44, 52, 60, 68, 76,
84, 92, 100, 106, 112, 116, 120, 124,
128, 132, 136, 140, 144, 150, 156, 164,
172, 180, 188, 196, 204, 212, 220, 228
};
static av_cold int escape130_decode_init(AVCodecContext *avctx)
{
Escape130Context *s = avctx->priv_data;
avctx->pix_fmt = AV_PIX_FMT_YUV420P;
if ((avctx->width & 1) || (avctx->height & 1)) {
av_log(avctx, AV_LOG_ERROR,
"Dimensions should be a multiple of two.\n");
return AVERROR_INVALIDDATA;
}
s->old_y_avg = av_malloc(avctx->width * avctx->height / 4);
s->buf1 = av_malloc(avctx->width * avctx->height * 3 / 2);
s->buf2 = av_malloc(avctx->width * avctx->height * 3 / 2);
if (!s->old_y_avg || !s->buf1 || !s->buf2) {
av_log(avctx, AV_LOG_ERROR, "Could not allocate buffer.\n");
return AVERROR(ENOMEM);
}
s->linesize[0] = avctx->width;
s->linesize[1] =
s->linesize[2] = avctx->width / 2;
s->new_y = s->buf1;
s->new_u = s->new_y + avctx->width * avctx->height;
s->new_v = s->new_u + avctx->width * avctx->height / 4;
s->old_y = s->buf2;
s->old_u = s->old_y + avctx->width * avctx->height;
s->old_v = s->old_u + avctx->width * avctx->height / 4;
memset(s->old_y, 0, avctx->width * avctx->height);
memset(s->old_u, 0x10, avctx->width * avctx->height / 4);
memset(s->old_v, 0x10, avctx->width * avctx->height / 4);
return 0;
}
static av_cold int escape130_decode_close(AVCodecContext *avctx)
{
Escape130Context *s = avctx->priv_data;
av_freep(&s->old_y_avg);
av_freep(&s->buf1);
av_freep(&s->buf2);
return 0;
}
static int decode_skip_count(GetBitContext* gb)
{
int value;
if (get_bits_left(gb) < 1+3)
return -1;
value = get_bits1(gb);
if (value)
return 0;
value = get_bits(gb, 3);
if (value)
return value;
value = get_bits(gb, 8);
if (value)
return value + 7;
value = get_bits(gb, 15);
if (value)
return value + 262;
return -1;
}
static int escape130_decode_frame(AVCodecContext *avctx, AVFrame *pic,
int *got_frame, AVPacket *avpkt)
{
int buf_size = avpkt->size;
Escape130Context *s = avctx->priv_data;
GetBitContext gb;
int ret;
uint8_t *old_y, *old_cb, *old_cr,
*new_y, *new_cb, *new_cr;
uint8_t *dstY, *dstU, *dstV;
unsigned old_y_stride, old_cb_stride, old_cr_stride,
new_y_stride, new_cb_stride, new_cr_stride;
unsigned total_blocks = avctx->width * avctx->height / 4,
block_index, block_x = 0;
unsigned y[4] = { 0 }, cb = 0x10, cr = 0x10;
int skip = -1, y_avg = 0, i, j;
uint8_t *ya = s->old_y_avg;
// first 16 bytes are header; no useful information in here
if (buf_size <= 16) {
av_log(avctx, AV_LOG_ERROR, "Insufficient frame data\n");
return AVERROR_INVALIDDATA;
}
if ((ret = ff_get_buffer(avctx, pic, 0)) < 0)
return ret;
if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)
return ret;
skip_bits_long(&gb, 16 * 8);
new_y = s->new_y;
new_cb = s->new_u;
new_cr = s->new_v;
new_y_stride = s->linesize[0];
new_cb_stride = s->linesize[1];
new_cr_stride = s->linesize[2];
old_y = s->old_y;
old_cb = s->old_u;
old_cr = s->old_v;
old_y_stride = s->linesize[0];
old_cb_stride = s->linesize[1];
old_cr_stride = s->linesize[2];
for (block_index = 0; block_index < total_blocks; block_index++) {
// Note that this call will make us skip the rest of the blocks
// if the frame ends prematurely.
if (skip == -1)
skip = decode_skip_count(&gb);
if (skip == -1) {
av_log(avctx, AV_LOG_ERROR, "Error decoding skip value\n");
return AVERROR_INVALIDDATA;
}
if (skip) {
y[0] = old_y[0];
y[1] = old_y[1];
y[2] = old_y[old_y_stride];
y[3] = old_y[old_y_stride + 1];
y_avg = ya[0];
cb = old_cb[0];
cr = old_cr[0];
} else {
if (get_bits1(&gb)) {
unsigned sign_selector = get_bits(&gb, 6);
unsigned difference_selector = get_bits(&gb, 2);
y_avg = 2 * get_bits(&gb, 5);
for (i = 0; i < 4; i++) {
y[i] = av_clip(y_avg + offset_table[difference_selector] *
sign_table[sign_selector][i], 0, 63);
}
} else if (get_bits1(&gb)) {
if (get_bits1(&gb)) {
y_avg = get_bits(&gb, 6);
} else {
unsigned adjust_index = get_bits(&gb, 3);
y_avg = (y_avg + luma_adjust[adjust_index]) & 63;
}
for (i = 0; i < 4; i++)
y[i] = y_avg;
}
if (get_bits1(&gb)) {
if (get_bits1(&gb)) {
cb = get_bits(&gb, 5);
cr = get_bits(&gb, 5);
} else {
unsigned adjust_index = get_bits(&gb, 3);
cb = (cb + chroma_adjust[0][adjust_index]) & 31;
cr = (cr + chroma_adjust[1][adjust_index]) & 31;
}
}
}
*ya++ = y_avg;
new_y[0] = y[0];
new_y[1] = y[1];
new_y[new_y_stride] = y[2];
new_y[new_y_stride + 1] = y[3];
*new_cb = cb;
*new_cr = cr;
old_y += 2;
old_cb++;
old_cr++;
new_y += 2;
new_cb++;
new_cr++;
block_x++;
if (block_x * 2 == avctx->width) {
block_x = 0;
old_y += old_y_stride * 2 - avctx->width;
old_cb += old_cb_stride - avctx->width / 2;
old_cr += old_cr_stride - avctx->width / 2;
new_y += new_y_stride * 2 - avctx->width;
new_cb += new_cb_stride - avctx->width / 2;
new_cr += new_cr_stride - avctx->width / 2;
}
skip--;
}
new_y = s->new_y;
new_cb = s->new_u;
new_cr = s->new_v;
dstY = pic->data[0];
dstU = pic->data[1];
dstV = pic->data[2];
for (j = 0; j < avctx->height; j++) {
for (i = 0; i < avctx->width; i++)
dstY[i] = new_y[i] << 2;
dstY += pic->linesize[0];
new_y += new_y_stride;
}
for (j = 0; j < avctx->height / 2; j++) {
for (i = 0; i < avctx->width / 2; i++) {
dstU[i] = chroma_vals[new_cb[i]];
dstV[i] = chroma_vals[new_cr[i]];
}
dstU += pic->linesize[1];
dstV += pic->linesize[2];
new_cb += new_cb_stride;
new_cr += new_cr_stride;
}
ff_dlog(avctx, "Frame data: provided %d bytes, used %d bytes\n",
buf_size, get_bits_count(&gb) >> 3);
FFSWAP(uint8_t*, s->old_y, s->new_y);
FFSWAP(uint8_t*, s->old_u, s->new_u);
FFSWAP(uint8_t*, s->old_v, s->new_v);
*got_frame = 1;
return buf_size;
}
const FFCodec ff_escape130_decoder = {
.p.name = "escape130",
.p.long_name = NULL_IF_CONFIG_SMALL("Escape 130"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_ESCAPE130,
.priv_data_size = sizeof(Escape130Context),
.init = escape130_decode_init,
.close = escape130_decode_close,
FF_CODEC_DECODE_CB(escape130_decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
};
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