/* * 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 };