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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
* Aura 2 decoder
*/
#include "avcodec.h"
#include "internal.h"
#include "libavutil/internal.h"
static av_cold int aura_decode_init(AVCodecContext *avctx)
{
/* width needs to be divisible by 4 for this codec to work */
if (avctx->width & 0x3)
return AVERROR(EINVAL);
avctx->pix_fmt = AV_PIX_FMT_YUV422P;
return 0;
}
static int aura_decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *pkt)
{
AVFrame *frame = data;
uint8_t *Y, *U, *V;
uint8_t val;
int x, y, ret;
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 AVERROR_INVALIDDATA;
}
/* pixel data starts 48 bytes in, after 3x16-byte tables */
buf += 48;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
Y = frame->data[0];
U = frame->data[1];
V = 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 += frame->linesize[0] - avctx->width;
U += frame->linesize[1] - (avctx->width >> 1);
V += frame->linesize[2] - (avctx->width >> 1);
}
*got_frame = 1;
return pkt->size;
}
const AVCodec ff_aura2_decoder = {
.name = "aura2",
.long_name = NULL_IF_CONFIG_SMALL("Auravision Aura 2"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_AURA2,
.init = aura_decode_init,
.decode = aura_decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
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