FFmpeg4/libavcodec/cljrdec.c

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2023-07-02 12:20:28 +00:00
/*
* Cirrus Logic AccuPak (CLJR) decoder
* Copyright (c) 2003 Alex Beregszaszi
*
* 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
* Cirrus Logic AccuPak decoder.
*/
#include "avcodec.h"
#include "get_bits.h"
#include "internal.h"
static int decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
GetBitContext gb;
AVFrame * const p = data;
int x, y, ret;
if (avctx->height <= 0 || avctx->width <= 0) {
av_log(avctx, AV_LOG_ERROR, "Invalid width or height\n");
return AVERROR_INVALIDDATA;
}
if (buf_size / avctx->height < avctx->width) {
av_log(avctx, AV_LOG_ERROR,
"Resolution larger than buffer size. Invalid header?\n");
return AVERROR_INVALIDDATA;
}
if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
return ret;
p->pict_type = AV_PICTURE_TYPE_I;
p->key_frame = 1;
init_get_bits(&gb, buf, buf_size * 8);
for (y = 0; y < avctx->height; y++) {
uint8_t *luma = &p->data[0][y * p->linesize[0]];
uint8_t *cb = &p->data[1][y * p->linesize[1]];
uint8_t *cr = &p->data[2][y * p->linesize[2]];
for (x = 0; x < avctx->width; x += 4) {
luma[3] = (get_bits(&gb, 5)*33) >> 2;
luma[2] = (get_bits(&gb, 5)*33) >> 2;
luma[1] = (get_bits(&gb, 5)*33) >> 2;
luma[0] = (get_bits(&gb, 5)*33) >> 2;
luma += 4;
*(cb++) = get_bits(&gb, 6) << 2;
*(cr++) = get_bits(&gb, 6) << 2;
}
}
*got_frame = 1;
return buf_size;
}
static av_cold int decode_init(AVCodecContext *avctx)
{
avctx->pix_fmt = AV_PIX_FMT_YUV411P;
return 0;
}
AVCodec ff_cljr_decoder = {
.name = "cljr",
.long_name = NULL_IF_CONFIG_SMALL("Cirrus Logic AccuPak"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_CLJR,
.init = decode_init,
.decode = decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
};