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FFmpeg/libavcodec/qoidec.c
Andreas Rheinhardt 563c2ed272 avcodec/qoidec: Remove unused-but-set variable
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-07-03 11:41:23 +02:00

126 lines
4.0 KiB
C

/*
* QOI image format
*
* 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 <stdlib.h>
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "internal.h"
#include "bytestream.h"
#include "codec_internal.h"
#include "thread.h"
#include "qoi.h"
static int qoi_decode_frame(AVCodecContext *avctx, AVFrame *p,
int *got_frame, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int ret, buf_size = avpkt->size;
int width, height, channels, space, run = 0;
uint8_t index[64][4] = { 0 };
uint8_t px[4] = { 0, 0, 0, 255 };
GetByteContext gb;
uint8_t *dst;
uint64_t len;
if (buf_size < 20)
return AVERROR_INVALIDDATA;
bytestream2_init(&gb, buf, buf_size);
bytestream2_skip(&gb, 4);
width = bytestream2_get_be32(&gb);
height = bytestream2_get_be32(&gb);
channels = bytestream2_get_byte(&gb);
space = bytestream2_get_byte(&gb);
switch (space) {
case 0: break;
case 1: avctx->color_trc = AVCOL_TRC_LINEAR; break;
default: return AVERROR_INVALIDDATA;
}
if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
return ret;
switch (channels) {
case 3: avctx->pix_fmt = AV_PIX_FMT_RGB24; break;
case 4: avctx->pix_fmt = AV_PIX_FMT_RGBA; break;
default: return AVERROR_INVALIDDATA;
}
if ((ret = ff_thread_get_buffer(avctx, p, 0)) < 0)
return ret;
dst = p->data[0];
len = width * height * channels;
for (int n = 0, off_x = 0; n < len; n += channels, off_x++) {
if (off_x >= width) {
off_x = 0;
dst += p->linesize[0];
}
if (run > 0) {
run--;
} else if (bytestream2_get_bytes_left(&gb) > 4) {
int chunk = bytestream2_get_byteu(&gb);
if (chunk == QOI_OP_RGB) {
bytestream2_get_bufferu(&gb, px, 3);
} else if (chunk == QOI_OP_RGBA) {
bytestream2_get_bufferu(&gb, px, 4);
} else if ((chunk & QOI_MASK_2) == QOI_OP_INDEX) {
memcpy(px, index[chunk], 4);
} else if ((chunk & QOI_MASK_2) == QOI_OP_DIFF) {
px[0] += ((chunk >> 4) & 0x03) - 2;
px[1] += ((chunk >> 2) & 0x03) - 2;
px[2] += ( chunk & 0x03) - 2;
} else if ((chunk & QOI_MASK_2) == QOI_OP_LUMA) {
int b2 = bytestream2_get_byteu(&gb);
int vg = (chunk & 0x3f) - 32;
px[0] += vg - 8 + ((b2 >> 4) & 0x0f);
px[1] += vg;
px[2] += vg - 8 + (b2 & 0x0f);
} else if ((chunk & QOI_MASK_2) == QOI_OP_RUN) {
run = chunk & 0x3f;
}
memcpy(index[QOI_COLOR_HASH(px) & 63], px, 4);
} else {
break;
}
memcpy(&dst[off_x * channels], px, channels);
}
p->key_frame = 1;
p->pict_type = AV_PICTURE_TYPE_I;
*got_frame = 1;
return buf_size;
}
const FFCodec ff_qoi_decoder = {
.p.name = "qoi",
.p.long_name = NULL_IF_CONFIG_SMALL("QOI (Quite OK Image format) image"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_QOI,
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
FF_CODEC_DECODE_CB(qoi_decode_frame),
};