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/*
* FITS demuxer
* Copyright (c) 2017 Paras Chadha
*
* 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
* FITS demuxer.
*/
#include "demux.h"
#include "internal.h"
#include "libavutil/opt.h"
#include "libavcodec/fits.h"
#define FITS_BLOCK_SIZE 2880
typedef struct FITSContext {
const AVClass *class;
AVRational framerate;
int first_image;
} FITSContext;
static int fits_probe(const AVProbeData *p)
{
const uint8_t *b = p->buf;
if (!memcmp(b, "SIMPLE = T", 30))
return AVPROBE_SCORE_MAX - 1;
return 0;
}
static int fits_read_header(AVFormatContext *s)
{
AVStream *st;
FITSContext * fits = s->priv_data;
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_FITS;
avpriv_set_pts_info(st, 64, fits->framerate.den, fits->framerate.num);
fits->first_image = 1;
return 0;
}
/**
* Parses header and checks that the current HDU contains image or not
* It also stores the header in the avbuf and stores the size of data part in data_size
* @param s pointer to AVFormat Context
* @param fits pointer to FITSContext
* @param header pointer to FITSHeader
* @param pkt pointer to AVPacket to store the header
* @param data_size to store the size of data part
* @return 1 if image found, 0 if any other extension and AVERROR code otherwise
*/
static int is_image(AVFormatContext *s, FITSContext *fits, FITSHeader *header,
AVPacket *pkt, uint64_t *data_size)
{
int i, ret, image = 0;
int64_t size = 0, t;
do {
const uint8_t *buf, *buf_end;
ret = av_append_packet(s->pb, pkt, FITS_BLOCK_SIZE);
if (ret < 0) {
return ret;
} else if (ret < FITS_BLOCK_SIZE) {
return AVERROR_INVALIDDATA;
}
ret = 0;
buf_end = pkt->data + pkt->size;
buf = buf_end - FITS_BLOCK_SIZE;
while(!ret && buf < buf_end) {
ret = avpriv_fits_header_parse_line(s, header, buf, NULL);
buf += 80;
}
} while (!ret);
if (ret < 0)
return ret;
image = fits->first_image || header->image_extension;
fits->first_image = 0;
if (header->groups) {
image = 0;
if (header->naxis > 1)
size = 1;
} else if (header->naxis) {
size = header->naxisn[0];
} else {
image = 0;
}
for (i = 1; i < header->naxis; i++) {
if(size && header->naxisn[i] > UINT64_MAX / size)
return AVERROR_INVALIDDATA;
size *= header->naxisn[i];
}
if(header->pcount > UINT64_MAX - size)
return AVERROR_INVALIDDATA;
size += header->pcount;
t = (abs(header->bitpix) >> 3) * ((int64_t) header->gcount);
if(size && t > INT64_MAX / size)
return AVERROR_INVALIDDATA;
size *= t;
if (!size) {
image = 0;
} else {
if(FITS_BLOCK_SIZE - 1 > INT64_MAX - size)
return AVERROR_INVALIDDATA;
size = ((size + FITS_BLOCK_SIZE - 1) / FITS_BLOCK_SIZE) * FITS_BLOCK_SIZE;
}
*data_size = size;
return image;
}
static int fits_read_packet(AVFormatContext *s, AVPacket *pkt)
{
uint64_t size;
FITSContext *fits = s->priv_data;
FITSHeader header;
int ret;
if (fits->first_image) {
avpriv_fits_header_init(&header, STATE_SIMPLE);
} else {
avpriv_fits_header_init(&header, STATE_XTENSION);
}
while ((ret = is_image(s, fits, &header, pkt, &size)) == 0) {
int64_t pos = avio_skip(s->pb, size);
if (pos < 0)
return pos;
avpriv_fits_header_init(&header, STATE_XTENSION);
av_packet_unref(pkt);
}
if (ret < 0)
return ret;
pkt->stream_index = 0;
pkt->flags |= AV_PKT_FLAG_KEY;
pkt->duration = 1;
// Header is sent with the first line removed...
pkt->data += 80;
pkt->size -= 80;
if (size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE - pkt->size)
return AVERROR(ERANGE);
ret = av_append_packet(s->pb, pkt, size);
if (ret < 0)
return ret;
return 0;
}
static const AVOption fits_options[] = {
{ "framerate", "set the framerate", offsetof(FITSContext, framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "1"}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
{ NULL },
};
static const AVClass fits_demuxer_class = {
.class_name = "FITS demuxer",
.item_name = av_default_item_name,
.option = fits_options,
.version = LIBAVUTIL_VERSION_INT,
.category = AV_CLASS_CATEGORY_DEMUXER,
};
const FFInputFormat ff_fits_demuxer = {
.p.name = "fits",
.p.long_name = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
.p.priv_class = &fits_demuxer_class,
.p.flags = AVFMT_NOTIMESTAMPS,
.priv_data_size = sizeof(FITSContext),
.read_probe = fits_probe,
.read_header = fits_read_header,
.read_packet = fits_read_packet,
};
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