1/* 2 * FITS muxer 3 * Copyright (c) 2017 Paras Chadha 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file 24 * FITS muxer. 25 */ 26 27#include "avio_internal.h" 28#include "internal.h" 29 30typedef struct FITSContext { 31 int first_image; 32} FITSContext; 33 34static int fits_write_header(AVFormatContext *s) 35{ 36 FITSContext *fitsctx = s->priv_data; 37 fitsctx->first_image = 1; 38 return 0; 39} 40 41/** 42 * Write one header line comprising of keyword and value(int) 43 * @param s AVFormat Context 44 * @param keyword pointer to the char array in which keyword is stored 45 * @param value the value corresponding to the keyword 46 * @param lines_written to keep track of lines written so far 47 * @return 0 48 */ 49static int write_keyword_value(AVFormatContext *s, const char *fmt, 50 const char *keyword, void *value, int *lines_written) 51{ 52 int len, ret; 53 uint8_t header[80]; 54 55 len = strlen(keyword); 56 memset(header, ' ', sizeof(header)); 57 memcpy(header, keyword, len); 58 59 header[8] = '='; 60 header[9] = ' '; 61 62 if (!strcmp(fmt, "%d")) { 63 ret = snprintf(header + 10, 70, fmt, *(int *)value); 64 } else { 65 ret = snprintf(header + 10, 70, fmt, *(float *)value); 66 } 67 68 memset(&header[ret + 10], ' ', sizeof(header) - (ret + 10)); 69 70 avio_write(s->pb, header, sizeof(header)); 71 *lines_written += 1; 72 return 0; 73} 74 75static int write_image_header(AVFormatContext *s) 76{ 77 AVStream *st = s->streams[0]; 78 AVCodecParameters *encctx = st->codecpar; 79 FITSContext *fitsctx = s->priv_data; 80 uint8_t buffer[80]; 81 int bitpix, naxis, naxis3 = 1, bzero = 0, rgb = 0, lines_written = 0, lines_left; 82 int pcount = 0, gcount = 1; 83 float datamax, datamin; 84 85 switch (encctx->format) { 86 case AV_PIX_FMT_GRAY8: 87 bitpix = 8; 88 naxis = 2; 89 datamin = 0; 90 datamax = 255; 91 break; 92 case AV_PIX_FMT_GRAY16BE: 93 bitpix = 16; 94 naxis = 2; 95 bzero = 32768; 96 datamin = 0; 97 datamax = 65535; 98 break; 99 case AV_PIX_FMT_GBRP: 100 case AV_PIX_FMT_GBRAP: 101 bitpix = 8; 102 naxis = 3; 103 rgb = 1; 104 if (encctx->format == AV_PIX_FMT_GBRP) { 105 naxis3 = 3; 106 } else { 107 naxis3 = 4; 108 } 109 datamin = 0; 110 datamax = 255; 111 break; 112 case AV_PIX_FMT_GBRP16BE: 113 case AV_PIX_FMT_GBRAP16BE: 114 bitpix = 16; 115 naxis = 3; 116 rgb = 1; 117 if (encctx->format == AV_PIX_FMT_GBRP16BE) { 118 naxis3 = 3; 119 } else { 120 naxis3 = 4; 121 } 122 bzero = 32768; 123 datamin = 0; 124 datamax = 65535; 125 break; 126 default: 127 return AVERROR(EINVAL); 128 } 129 130 if (fitsctx->first_image) { 131 memcpy(buffer, "SIMPLE = ", 10); 132 memset(buffer + 10, ' ', 70); 133 buffer[29] = 'T'; 134 avio_write(s->pb, buffer, sizeof(buffer)); 135 } else { 136 memcpy(buffer, "XTENSION= 'IMAGE '", 20); 137 memset(buffer + 20, ' ', 60); 138 avio_write(s->pb, buffer, sizeof(buffer)); 139 } 140 lines_written++; 141 142 write_keyword_value(s, "%d", "BITPIX", &bitpix, &lines_written); // no of bits per pixel 143 write_keyword_value(s, "%d", "NAXIS", &naxis, &lines_written); // no of dimensions of image 144 write_keyword_value(s, "%d", "NAXIS1", &encctx->width, &lines_written); // first dimension i.e. width 145 write_keyword_value(s, "%d", "NAXIS2", &encctx->height, &lines_written); // second dimension i.e. height 146 147 if (rgb) 148 write_keyword_value(s, "%d", "NAXIS3", &naxis3, &lines_written); // third dimension to store RGBA planes 149 150 if (!fitsctx->first_image) { 151 write_keyword_value(s, "%d", "PCOUNT", &pcount, &lines_written); 152 write_keyword_value(s, "%d", "GCOUNT", &gcount, &lines_written); 153 } else { 154 fitsctx->first_image = 0; 155 } 156 157 write_keyword_value(s, "%g", "DATAMIN", &datamin, &lines_written); 158 write_keyword_value(s, "%g", "DATAMAX", &datamax, &lines_written); 159 160 /* 161 * Since FITS does not support unsigned 16 bit integers, 162 * BZERO = 32768 is used to store unsigned 16 bit integers as 163 * signed integers so that it can be read properly. 164 */ 165 if (bitpix == 16) 166 write_keyword_value(s, "%d", "BZERO", &bzero, &lines_written); 167 168 if (rgb) { 169 memcpy(buffer, "CTYPE3 = 'RGB '", 20); 170 memset(buffer + 20, ' ', 60); 171 avio_write(s->pb, buffer, sizeof(buffer)); 172 lines_written++; 173 } 174 175 memcpy(buffer, "END", 3); 176 memset(buffer + 3, ' ', 77); 177 avio_write(s->pb, buffer, sizeof(buffer)); 178 lines_written++; 179 180 lines_left = ((lines_written + 35) / 36) * 36 - lines_written; 181 ffio_fill(s->pb, ' ', sizeof(buffer) * lines_left); 182 return 0; 183} 184 185static int fits_write_packet(AVFormatContext *s, AVPacket *pkt) 186{ 187 int ret = write_image_header(s); 188 if (ret < 0) 189 return ret; 190 avio_write(s->pb, pkt->data, pkt->size); 191 return 0; 192} 193 194const AVOutputFormat ff_fits_muxer = { 195 .name = "fits", 196 .long_name = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"), 197 .extensions = "fits", 198 .priv_data_size = sizeof(FITSContext), 199 .audio_codec = AV_CODEC_ID_NONE, 200 .video_codec = AV_CODEC_ID_FITS, 201 .write_header = fits_write_header, 202 .write_packet = fits_write_packet, 203}; 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