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/*
* Aura 2 decoder
*
* 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 libavcodec/aura.c
* Aura 2 decoder
*/
#include "avcodec.h"
typedef struct AuraDecodeContext {
AVCodecContext *avctx;
AVFrame frame;
} AuraDecodeContext;
static av_cold int aura_decode_init(AVCodecContext *avctx)
{
AuraDecodeContext *s = avctx->priv_data;
s->avctx = avctx;
/* width needs to be divisible by 4 for this codec to work */
if (avctx->width & 0x3)
return -1;
avctx->pix_fmt = PIX_FMT_YUV422P;
return 0;
}
static int aura_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *pkt)
{
AuraDecodeContext *s=avctx->priv_data;
uint8_t *Y, *U, *V;
uint8_t val;
int x, y;
const uint8_t *buf = pkt->data;
/* prediction error tables (make it clear that they are signed values) */
const int8_t *delta_table = (const int8_t*)buf + 16;
if (pkt->size != 48 + avctx->height * avctx->width) {
av_log(avctx, AV_LOG_ERROR, "got a buffer with %d bytes when %d were expected\n",
pkt->size, 48 + avctx->height * avctx->width);
return -1;
}
/* pixel data starts 48 bytes in, after 3x16-byte tables */
buf += 48;
if(s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
s->frame.reference = 0;
if(avctx->get_buffer(avctx, &s->frame) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
Y = s->frame.data[0];
U = s->frame.data[1];
V = s->frame.data[2];
/* iterate through each line in the height */
for (y = 0; y < avctx->height; y++) {
/* reset predictors */
val = *buf++;
U[0] = val & 0xF0;
Y[0] = val << 4;
val = *buf++;
V[0] = val & 0xF0;
Y[1] = Y[0] + delta_table[val & 0xF];
Y += 2; U++; V++;
/* iterate through the remaining pixel groups (4 pixels/group) */
for (x = 1; x < (avctx->width >> 1); x++) {
val = *buf++;
U[0] = U[-1] + delta_table[val >> 4];
Y[0] = Y[-1] + delta_table[val & 0xF];
val = *buf++;
V[0] = V[-1] + delta_table[val >> 4];
Y[1] = Y[ 0] + delta_table[val & 0xF];
Y += 2; U++; V++;
}
Y += s->frame.linesize[0] - avctx->width;
U += s->frame.linesize[1] - (avctx->width >> 1);
V += s->frame.linesize[2] - (avctx->width >> 1);
}
*data_size=sizeof(AVFrame);
*(AVFrame*)data= s->frame;
return pkt->size;
}
static av_cold int aura_decode_end(AVCodecContext *avctx)
{
AuraDecodeContext *s = avctx->priv_data;
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
return 0;
}
AVCodec aura2_decoder = {
"aura2",
AVMEDIA_TYPE_VIDEO,
CODEC_ID_AURA2,
sizeof(AuraDecodeContext),
aura_decode_init,
NULL,
aura_decode_end,
aura_decode_frame,
CODEC_CAP_DR1,
NULL,
.long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
};
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