/*
* FITS image decoder
* 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 image decoder
*
* Specification: https://fits.gsfc.nasa.gov/fits_standard.html Version 3.0
*
* Support all 2d images alongwith, bzero, bscale and blank keywords.
* RGBA images are supported as NAXIS3 = 3 or 4 i.e. Planes in RGBA order. Also CTYPE = 'RGB ' should be present.
* Also to interpret data, values are linearly scaled using min-max scaling but not RGB images.
*/
#include "avcodec.h"
#include "internal.h"
#include <float.h>
#include "libavutil/intreadwrite.h"
#include "libavutil/intfloat.h"
#include "libavutil/dict.h"
#include "libavutil/opt.h"
#include "fits.h"
typedef struct FITSContext {
const AVClass *class;
int blank_val;
} FITSContext;
/**
* Calculate the data_min and data_max values from the data.
* This is called if the values are not present in the header.
* @param ptr8 pointer to the data
* @param header pointer to the header
* @param end pointer to end of packet
* @return 0 if calculated successfully otherwise AVERROR_INVALIDDATA
*/
static int fill_data_min_max(const uint8_t *ptr8, FITSHeader *header, const uint8_t *end)
{
uint8_t t8;
int16_t t16;
int32_t t32;
int64_t t64;
float tflt;
double tdbl;
int i, j;
header->data_min = DBL_MAX;
header->data_max = DBL_MIN;
switch (header->bitpix) {
#define CASE_N(a, t, rd) \
case a: \
for (i = 0; i < header->naxisn[1]; i++) { \
for (j = 0; j < header->naxisn[0]; j++) { \
t = rd; \
if (!header->blank_found || t != header->blank) { \
if (t > header->data_max) \
header->data_max = t; \
if (t < header->data_min) \
header->data_min = t; \
} \
ptr8 += abs(a) >> 3; \
} \
} \
break
CASE_N(-64, tdbl, av_int2double(AV_RB64(ptr8)));
CASE_N(-32, tflt, av_int2float(AV_RB32(ptr8)));
CASE_N(8, t8, ptr8[0]);
CASE_N(16, t16, AV_RB16(ptr8));
CASE_N(32, t32, AV_RB32(ptr8));
CASE_N(64, t64, AV_RB64(ptr8));
default:
return AVERROR_INVALIDDATA;
}
return 0;
}
/**
* Read the fits header and store the values in FITSHeader pointed by header
* @param avctx AVCodec context
* @param ptr pointer to pointer to the data
* @param header pointer to the FITSHeader
* @param end pointer to end of packet
* @param metadata pointer to pointer to AVDictionary to store metadata
* @return 0 if calculated successfully otherwise AVERROR_INVALIDDATA
*/
static int fits_read_header(AVCodecContext *avctx, const uint8_t **ptr, FITSHeader *header,
const uint8_t *end, AVDictionary **metadata)
{
const uint8_t *ptr8 = *ptr;
int lines_read, bytes_left, i, ret;
size_t size;
lines_read = 1; // to account for first header line, SIMPLE or XTENSION which is not included in packet...
avpriv_fits_header_init(header, STATE_BITPIX);
do {
if (end - ptr8 < 80)
return AVERROR_INVALIDDATA;
ret = avpriv_fits_header_parse_line(avctx, header, ptr8, &metadata);
ptr8 += 80;
lines_read++;
} while (!ret);
if (ret < 0)
return ret;
bytes_left = (((lines_read + 35) / 36) * 36 - lines_read) * 80;
if (end - ptr8 < bytes_left)
return AVERROR_INVALIDDATA;
ptr8 += bytes_left;
if (header->rgb && (header->naxis != 3 || (header->naxisn[2] != 3 && header->naxisn[2] != 4))) {
av_log(avctx, AV_LOG_ERROR, "File contains RGB image but NAXIS = %d and NAXIS3 = %d\n", header->naxis, header->naxisn[2]);
return AVERROR_INVALIDDATA;
}
if (!header->rgb && header->naxis != 2) {
av_log(avctx, AV_LOG_ERROR, "unsupported number of dimensions, NAXIS = %d\n", header->naxis);
return AVERROR_INVALIDDATA;
}
if (header->blank_found && (header->bitpix == -32 || header->bitpix == -64)) {
av_log(avctx, AV_LOG_WARNING, "BLANK keyword found but BITPIX = %d\n. Ignoring BLANK", header->bitpix);
header->blank_found = 0;
}
size = abs(header->bitpix) >> 3;
for (i = 0; i < header->naxis; i++) {
if (header->naxisn[i] > SIZE_MAX / size) {
av_log(avctx, AV_LOG_ERROR, "unsupported size of FITS image");
return AVERROR_INVALIDDATA;
}
size *= header->naxisn[i];
}
if (end - ptr8 < size)
return AVERROR_INVALIDDATA;
*ptr = ptr8;
if (!header->rgb && (!header->data_min_found || !header->data_max_found)) {
ret = fill_data_min_max(ptr8, header, end);
if (ret < 0) {
av_log(avctx, AV_LOG_ERROR, "invalid BITPIX, %d\n", header->bitpix);
return ret;
}
} else {
/*
* instead of applying bscale and bzero to every element,
* we can do inverse transformation on data_min and data_max
*/
header->data_min = (header->data_min - header->bzero) / header->bscale;
header->data_max = (header->data_max - header->bzero) / header->bscale;
}
return 0;
}
static int fits_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
{
AVFrame *p=data;
const uint8_t *ptr8 = avpkt->data, *end;
uint8_t t8;
int16_t t16;
int32_t t32;
int64_t t64;
float tflt;
double tdbl;
int ret, i, j, k;
const int map[] = {2, 0, 1, 3}; // mapping from GBRA -> RGBA as RGBA is to be stored in FITS file..
uint8_t *dst8;
uint16_t *dst16;
uint64_t t;
FITSHeader header;
FITSContext * fitsctx = avctx->priv_data;
end = ptr8 + avpkt->size;
p->metadata = NULL;
ret = fits_read_header(avctx, &ptr8, &header, end, &p->metadata);
if (ret < 0)
return ret;
if (header.rgb) {
if (header.bitpix == 8) {
if (header.naxisn[2] == 3) {
avctx->pix_fmt = AV_PIX_FMT_GBRP;
} else {
avctx->pix_fmt = AV_PIX_FMT_GBRAP;
}
} else if (header.bitpix == 16) {
if (header.naxisn[2] == 3) {
avctx->pix_fmt = AV_PIX_FMT_GBRP16;
} else {
avctx->pix_fmt = AV_PIX_FMT_GBRAP16;
}
} else {
av_log(avctx, AV_LOG_ERROR, "unsupported BITPIX = %d\n", header.bitpix);
return AVERROR_INVALIDDATA;
}
} else {
if (header.bitpix == 8) {
avctx->pix_fmt = AV_PIX_FMT_GRAY8;
} else {
avctx->pix_fmt = AV_PIX_FMT_GRAY16;
}
}
if ((ret = ff_set_dimensions(avctx, header.naxisn[0], header.naxisn[1])) < 0)
return ret;
if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
return ret;
/*
* FITS stores images with bottom row first. Therefore we have
* to fill the image from bottom to top.
*/
if (header.rgb) {
switch(header.bitpix) {
#define CASE_RGB(cas, dst, type, dref) \
case cas: \
for (k = 0; k < header.naxisn[2]; k++) { \
for (i = 0; i < avctx->height; i++) { \
dst = (type *) (p->data[map[k]] + (avctx->height - i - 1) * p->linesize[map[k]]); \
for (j = 0; j < avctx->width; j++) { \
t32 = dref(ptr8); \
if (!header.blank_found || t32 != header.blank) { \
t = t32 * header.bscale + header.bzero; \
} else { \
t = fitsctx->blank_val; \
} \
*dst++ = (type) t; \
ptr8 += cas >> 3; \
} \
} \
} \
break
CASE_RGB(8, dst8, uint8_t, *);
CASE_RGB(16, dst16, uint16_t, AV_RB16);
}
} else {
switch (header.bitpix) {
#define CASE_GRAY(cas, dst, type, t, rd) \
case cas: \
for (i = 0; i < avctx->height; i++) { \
dst = (type *) (p->data[0] + (avctx->height-i-1)* p->linesize[0]); \
for (j = 0; j < avctx->width; j++) { \
t = rd; \
if (!header.blank_found || t != header.blank) { \
*dst++ = ((t - header.data_min) * ((1 << (sizeof(type) * 8)) - 1)) / (header.data_max - header.data_min); \
} else { \
*dst++ = fitsctx->blank_val; \
} \
ptr8 += abs(cas) >> 3; \
} \
} \
break
CASE_GRAY(-64, dst16, uint16_t, tdbl, av_int2double(AV_RB64(ptr8)));
CASE_GRAY(-32, dst16, uint16_t, tflt, av_int2float(AV_RB32(ptr8)));
CASE_GRAY(8, dst8, uint8_t, t8, ptr8[0]);
CASE_GRAY(16, dst16, uint16_t, t16, AV_RB16(ptr8));
CASE_GRAY(32, dst16, uint16_t, t32, AV_RB32(ptr8));
CASE_GRAY(64, dst16, uint16_t, t64, AV_RB64(ptr8));
default:
av_log(avctx, AV_LOG_ERROR, "invalid BITPIX, %d\n", header.bitpix);
return AVERROR_INVALIDDATA;
}
}
p->key_frame = 1;
p->pict_type = AV_PICTURE_TYPE_I;
*got_frame = 1;
return avpkt->size;
}
static const AVOption fits_options[] = {
{ "blank_value", "value that is used to replace BLANK pixels in data array", offsetof(FITSContext, blank_val), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 65535, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM},
{ NULL },
};
static const AVClass fits_decoder_class = {
.class_name = "FITS decoder",
.item_name = av_default_item_name,
.option = fits_options,
.version = LIBAVUTIL_VERSION_INT,
};
AVCodec ff_fits_decoder = {
.name = "fits",
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_FITS,
.priv_data_size = sizeof(FITSContext),
.decode = fits_decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
.priv_class = &fits_decoder_class
};