/*
* 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 "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_freep(&s->old_y_avg);
av_freep(&s->buf1);
av_freep(&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, void *data,
int *got_frame, AVPacket *avpkt)
{
int buf_size = avpkt->size;
Escape130Context *s = avctx->priv_data;
AVFrame *pic = 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;
}
AVCodec ff_escape130_decoder = {
.name = "escape130",
.long_name = NULL_IF_CONFIG_SMALL("Escape 130"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_ESCAPE130,
.priv_data_size = sizeof(Escape130Context),
.init = escape130_decode_init,
.close = escape130_decode_close,
.decode = escape130_decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
};