335 lines
11 KiB
C
335 lines
11 KiB
C
/*
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* FITS image decoder
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* Copyright (c) 2017 Paras Chadha
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* FITS image decoder
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*
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* Specification: https://fits.gsfc.nasa.gov/fits_standard.html Version 3.0
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*
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* Support all 2d images alongwith, bzero, bscale and blank keywords.
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* RGBA images are supported as NAXIS3 = 3 or 4 i.e. Planes in RGBA order. Also CTYPE = 'RGB ' should be present.
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* Also to interpret data, values are linearly scaled using min-max scaling but not RGB images.
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*/
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#include "avcodec.h"
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#include "codec_internal.h"
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#include "decode.h"
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#include <float.h>
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#include "libavutil/intreadwrite.h"
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#include "libavutil/intfloat.h"
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#include "libavutil/dict.h"
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#include "libavutil/opt.h"
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#include "fits.h"
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typedef struct FITSContext {
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const AVClass *class;
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int blank_val;
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} FITSContext;
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/**
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* Calculate the data_min and data_max values from the data.
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* This is called if the values are not present in the header.
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* @param ptr8 pointer to the data
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* @param header pointer to the header
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* @param end pointer to end of packet
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* @return 0 if calculated successfully otherwise AVERROR_INVALIDDATA
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*/
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static int fill_data_min_max(const uint8_t *ptr8, FITSHeader *header, const uint8_t *end)
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{
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uint8_t t8;
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int16_t t16;
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int32_t t32;
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int64_t t64;
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float tflt;
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double tdbl;
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int i, j;
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header->data_min = DBL_MAX;
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header->data_max = -DBL_MAX;
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switch (header->bitpix) {
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#define CASE_N(a, t, rd) \
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case a: \
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for (i = 0; i < header->naxisn[1]; i++) { \
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for (j = 0; j < header->naxisn[0]; j++) { \
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t = rd; \
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if (!header->blank_found || t != header->blank) { \
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if (t > header->data_max) \
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header->data_max = t; \
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if (t < header->data_min) \
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header->data_min = t; \
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} \
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ptr8 += abs(a) >> 3; \
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} \
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} \
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break
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CASE_N(-64, tdbl, av_int2double(AV_RB64(ptr8)));
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CASE_N(-32, tflt, av_int2float(AV_RB32(ptr8)));
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CASE_N(8, t8, ptr8[0]);
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CASE_N(16, t16, AV_RB16(ptr8));
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CASE_N(32, t32, AV_RB32(ptr8));
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CASE_N(64, t64, AV_RB64(ptr8));
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default:
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return AVERROR_INVALIDDATA;
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}
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return 0;
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}
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/**
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* Read the fits header and store the values in FITSHeader pointed by header
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* @param avctx AVCodec context
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* @param ptr pointer to pointer to the data
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* @param header pointer to the FITSHeader
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* @param end pointer to end of packet
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* @param metadata pointer to pointer to AVDictionary to store metadata
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* @return 0 if calculated successfully otherwise AVERROR_INVALIDDATA
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*/
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static int fits_read_header(AVCodecContext *avctx, const uint8_t **ptr, FITSHeader *header,
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const uint8_t *end, AVDictionary **metadata)
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{
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const uint8_t *ptr8 = *ptr;
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int lines_read, bytes_left, i, ret;
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size_t size;
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lines_read = 1; // to account for first header line, SIMPLE or XTENSION which is not included in packet...
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avpriv_fits_header_init(header, STATE_BITPIX);
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do {
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if (end - ptr8 < 80)
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return AVERROR_INVALIDDATA;
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ret = avpriv_fits_header_parse_line(avctx, header, ptr8, &metadata);
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ptr8 += 80;
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lines_read++;
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} while (!ret);
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if (ret < 0)
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return ret;
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bytes_left = (((lines_read + 35) / 36) * 36 - lines_read) * 80;
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if (end - ptr8 < bytes_left)
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return AVERROR_INVALIDDATA;
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ptr8 += bytes_left;
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if (header->rgb && (header->naxis != 3 || (header->naxisn[2] != 3 && header->naxisn[2] != 4))) {
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av_log(avctx, AV_LOG_ERROR, "File contains RGB image but NAXIS = %d and NAXIS3 = %d\n", header->naxis, header->naxisn[2]);
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return AVERROR_INVALIDDATA;
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}
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if (!header->rgb && header->naxis != 2) {
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av_log(avctx, AV_LOG_ERROR, "unsupported number of dimensions, NAXIS = %d\n", header->naxis);
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return AVERROR_INVALIDDATA;
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}
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if (header->blank_found && (header->bitpix == -32 || header->bitpix == -64)) {
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av_log(avctx, AV_LOG_WARNING, "BLANK keyword found but BITPIX = %d\n. Ignoring BLANK", header->bitpix);
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header->blank_found = 0;
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}
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size = abs(header->bitpix) >> 3;
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for (i = 0; i < header->naxis; i++) {
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if (size == 0 || header->naxisn[i] > SIZE_MAX / size) {
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av_log(avctx, AV_LOG_ERROR, "unsupported size of FITS image");
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return AVERROR_INVALIDDATA;
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}
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size *= header->naxisn[i];
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}
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if (end - ptr8 < size)
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return AVERROR_INVALIDDATA;
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*ptr = ptr8;
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if (!header->rgb && (!header->data_min_found || !header->data_max_found)) {
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ret = fill_data_min_max(ptr8, header, end);
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if (ret < 0) {
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av_log(avctx, AV_LOG_ERROR, "invalid BITPIX, %d\n", header->bitpix);
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return ret;
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}
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} else {
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/*
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* instead of applying bscale and bzero to every element,
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* we can do inverse transformation on data_min and data_max
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*/
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header->data_min = (header->data_min - header->bzero) / header->bscale;
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header->data_max = (header->data_max - header->bzero) / header->bscale;
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}
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if (!header->rgb && header->data_min >= header->data_max) {
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if (header->data_min > header->data_max) {
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av_log(avctx, AV_LOG_ERROR, "data min/max (%g %g) is invalid\n", header->data_min, header->data_max);
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return AVERROR_INVALIDDATA;
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}
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av_log(avctx, AV_LOG_WARNING, "data min/max indicates a blank image\n");
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header->data_max ++;
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}
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return 0;
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}
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static int fits_decode_frame(AVCodecContext *avctx, AVFrame *p,
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int *got_frame, AVPacket *avpkt)
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{
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const uint8_t *ptr8 = avpkt->data, *end;
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uint8_t t8;
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int16_t t16;
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int32_t t32;
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int64_t t64;
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float tflt;
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double tdbl;
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int ret, i, j, k;
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const int map[] = {2, 0, 1, 3}; // mapping from GBRA -> RGBA as RGBA is to be stored in FITS file..
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uint8_t *dst8;
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uint16_t *dst16;
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uint64_t t;
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FITSHeader header;
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FITSContext * fitsctx = avctx->priv_data;
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end = ptr8 + avpkt->size;
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p->metadata = NULL;
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ret = fits_read_header(avctx, &ptr8, &header, end, &p->metadata);
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if (ret < 0)
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return ret;
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if (header.rgb) {
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if (header.bitpix == 8) {
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if (header.naxisn[2] == 3) {
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avctx->pix_fmt = AV_PIX_FMT_GBRP;
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} else {
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avctx->pix_fmt = AV_PIX_FMT_GBRAP;
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}
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} else if (header.bitpix == 16) {
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if (header.naxisn[2] == 3) {
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avctx->pix_fmt = AV_PIX_FMT_GBRP16;
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} else {
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avctx->pix_fmt = AV_PIX_FMT_GBRAP16;
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}
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} else {
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av_log(avctx, AV_LOG_ERROR, "unsupported BITPIX = %d\n", header.bitpix);
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return AVERROR_INVALIDDATA;
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}
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} else {
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if (header.bitpix == 8) {
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avctx->pix_fmt = AV_PIX_FMT_GRAY8;
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} else {
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avctx->pix_fmt = AV_PIX_FMT_GRAY16;
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}
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}
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if ((ret = ff_set_dimensions(avctx, header.naxisn[0], header.naxisn[1])) < 0)
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return ret;
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if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
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return ret;
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/*
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* FITS stores images with bottom row first. Therefore we have
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* to fill the image from bottom to top.
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*/
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if (header.rgb) {
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switch(header.bitpix) {
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#define CASE_RGB(cas, dst, type, dref) \
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case cas: \
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for (k = 0; k < header.naxisn[2]; k++) { \
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for (i = 0; i < avctx->height; i++) { \
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dst = (type *) (p->data[map[k]] + (avctx->height - i - 1) * p->linesize[map[k]]); \
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for (j = 0; j < avctx->width; j++) { \
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t32 = dref(ptr8); \
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if (!header.blank_found || t32 != header.blank) { \
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t = t32 * header.bscale + header.bzero; \
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} else { \
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t = fitsctx->blank_val; \
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} \
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*dst++ = (type) t; \
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ptr8 += cas >> 3; \
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} \
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} \
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} \
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break
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CASE_RGB(8, dst8, uint8_t, *);
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CASE_RGB(16, dst16, uint16_t, AV_RB16);
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}
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} else {
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double scale = header.data_max - header.data_min;
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if (scale <= 0 || !isfinite(scale)) {
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scale = 1;
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}
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scale = 1/scale;
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switch (header.bitpix) {
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#define CASE_GRAY(cas, dst, type, t, rd) \
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case cas: \
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for (i = 0; i < avctx->height; i++) { \
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dst = (type *) (p->data[0] + (avctx->height-i-1)* p->linesize[0]); \
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for (j = 0; j < avctx->width; j++) { \
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t = rd; \
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if (!header.blank_found || t != header.blank) { \
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*dst++ = lrint(((t - header.data_min) * ((1 << (sizeof(type) * 8)) - 1)) * scale); \
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} else { \
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*dst++ = fitsctx->blank_val; \
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} \
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ptr8 += abs(cas) >> 3; \
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} \
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} \
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break
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CASE_GRAY(-64, dst16, uint16_t, tdbl, av_int2double(AV_RB64(ptr8)));
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CASE_GRAY(-32, dst16, uint16_t, tflt, av_int2float(AV_RB32(ptr8)));
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CASE_GRAY(8, dst8, uint8_t, t8, ptr8[0]);
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CASE_GRAY(16, dst16, uint16_t, t16, AV_RB16(ptr8));
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CASE_GRAY(32, dst16, uint16_t, t32, AV_RB32(ptr8));
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CASE_GRAY(64, dst16, uint16_t, t64, AV_RB64(ptr8));
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default:
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av_log(avctx, AV_LOG_ERROR, "invalid BITPIX, %d\n", header.bitpix);
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return AVERROR_INVALIDDATA;
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}
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}
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p->flags |= AV_FRAME_FLAG_KEY;
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p->pict_type = AV_PICTURE_TYPE_I;
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*got_frame = 1;
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return avpkt->size;
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}
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static const AVOption fits_options[] = {
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{ "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},
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{ NULL },
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};
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static const AVClass fits_decoder_class = {
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.class_name = "FITS decoder",
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.item_name = av_default_item_name,
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.option = fits_options,
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.version = LIBAVUTIL_VERSION_INT,
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.category = AV_CLASS_CATEGORY_DECODER,
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};
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const FFCodec ff_fits_decoder = {
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.p.name = "fits",
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.p.type = AVMEDIA_TYPE_VIDEO,
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.p.id = AV_CODEC_ID_FITS,
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.p.capabilities = AV_CODEC_CAP_DR1,
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CODEC_LONG_NAME("Flexible Image Transport System"),
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.p.priv_class = &fits_decoder_class,
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.priv_data_size = sizeof(FITSContext),
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FF_CODEC_DECODE_CB(fits_decode_frame),
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};
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