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FFmpeg/libavcodec/aura.c
Andreas Rheinhardt a247ac640d avcodec: Constify AVCodecs
Given that the AVCodec.next pointer has now been removed, most of the
AVCodecs are not modified at all any more and can therefore be made
const (as this patch does); the only exceptions are the very few codecs
for external libraries that have a init_static_data callback.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
2021-04-27 10:43:15 -03:00

110 lines
3.3 KiB
C

/*
* 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,
};