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FFmpeg/libavcodec/pgxdec.c

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/*
* PGX image format
* Copyright (c) 2020 Gautam Ramakrishnan
*
* 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 "avcodec.h"
#include "internal.h"
#include "bytestream.h"
#include "libavutil/imgutils.h"
static int pgx_get_number(AVCodecContext *avctx, GetByteContext *g, int *number) {
int ret = AVERROR_INVALIDDATA;
char digit;
*number = 0;
while (1) {
uint64_t temp;
if (!bytestream2_get_bytes_left(g))
return AVERROR_INVALIDDATA;
digit = bytestream2_get_byte(g);
if (digit == ' ' || digit == 0xA || digit == 0xD)
break;
else if (digit < '0' || digit > '9')
return AVERROR_INVALIDDATA;
temp = (uint64_t)10 * (*number) + (digit - '0');
if (temp > INT_MAX)
return AVERROR_INVALIDDATA;
*number = temp;
ret = 0;
}
return ret;
}
static int pgx_decode_header(AVCodecContext *avctx, GetByteContext *g,
int *depth, int *width, int *height,
int *sign)
{
int byte;
if (bytestream2_get_bytes_left(g) < 6) {
return AVERROR_INVALIDDATA;
}
bytestream2_skip(g, 6);
// Is the component signed?
byte = bytestream2_peek_byte(g);
if (byte == '+') {
*sign = 0;
bytestream2_skip(g, 1);
} else if (byte == '-') {
*sign = 1;
bytestream2_skip(g, 1);
} else if (byte == 0)
goto error;
byte = bytestream2_peek_byte(g);
if (byte == ' ')
bytestream2_skip(g, 1);
else if (byte == 0)
goto error;
if (pgx_get_number(avctx, g, depth))
goto error;
if (pgx_get_number(avctx, g, width))
goto error;
if (pgx_get_number(avctx, g, height))
goto error;
if (bytestream2_peek_byte(g) == 0xA)
bytestream2_skip(g, 1);
return 0;
error:
av_log(avctx, AV_LOG_ERROR, "Error in decoding header.\n");
return AVERROR_INVALIDDATA;
}
#define WRITE_FRAME(D, PIXEL, suffix) \
static inline void write_frame_ ##D(AVFrame *frame, GetByteContext *g, \
int width, int height, int sign, int depth) \
{ \
int i, j; \
for (i = 0; i < height; i++) { \
PIXEL *line = (PIXEL*)frame->data[0] + i*frame->linesize[0]/sizeof(PIXEL); \
for (j = 0; j < width; j++) { \
unsigned val; \
if (sign) \
val = (PIXEL)bytestream2_get_ ##suffix(g) + (1 << (depth - 1)); \
else \
val = bytestream2_get_ ##suffix(g); \
val <<= (D - depth); \
*(line + j) = val; \
} \
} \
} \
WRITE_FRAME(8, int8_t, byte)
WRITE_FRAME(16, int16_t, be16)
static int pgx_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame, AVPacket *avpkt)
{
AVFrame *p = data;
int ret;
int bpp;
int width, height, depth;
int sign = 0;
GetByteContext g;
bytestream2_init(&g, avpkt->data, avpkt->size);
if ((ret = pgx_decode_header(avctx, &g, &depth, &width, &height, &sign)) < 0)
return ret;
if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
return ret;
if (depth > 0 && depth <= 8) {
avctx->pix_fmt = AV_PIX_FMT_GRAY8;
bpp = 8;
} else if (depth > 0 && depth <= 16) {
avctx->pix_fmt = AV_PIX_FMT_GRAY16;
bpp = 16;
} else {
av_log(avctx, AV_LOG_ERROR, "depth %d is invalid or unsupported.\n", depth);
return AVERROR_PATCHWELCOME;
}
if (bytestream2_get_bytes_left(&g) < width * height * (bpp >> 3))
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;
avctx->bits_per_raw_sample = depth;
if (bpp == 8)
write_frame_8(p, &g, width, height, sign, depth);
else if (bpp == 16)
write_frame_16(p, &g, width, height, sign, depth);
*got_frame = 1;
return 0;
}
AVCodec ff_pgx_decoder = {
.name = "pgx",
.long_name = NULL_IF_CONFIG_SMALL("PGX (JPEG2000 Test Format)"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_PGX,
.decode = pgx_decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
};