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
30 typedef struct FITSContext {
31 int first_image;
32 } FITSContext;
33
fits_write_header(AVFormatContext * s)34 static 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 */
write_keyword_value(AVFormatContext * s,const char * fmt,const char * keyword,void * value,int * lines_written)49 static 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
write_image_header(AVFormatContext * s)75 static 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
fits_write_packet(AVFormatContext * s,AVPacket * pkt)185 static 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
194 const 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 };
204