1 /*
2 * FITS image decoder
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 image decoder
25 *
26 * Specification: https://fits.gsfc.nasa.gov/fits_standard.html Version 3.0
27 *
28 * Support all 2d images alongwith, bzero, bscale and blank keywords.
29 * RGBA images are supported as NAXIS3 = 3 or 4 i.e. Planes in RGBA order. Also CTYPE = 'RGB ' should be present.
30 * Also to interpret data, values are linearly scaled using min-max scaling but not RGB images.
31 */
32
33 #include "avcodec.h"
34 #include "codec_internal.h"
35 #include "internal.h"
36 #include <float.h>
37 #include "libavutil/intreadwrite.h"
38 #include "libavutil/intfloat.h"
39 #include "libavutil/dict.h"
40 #include "libavutil/opt.h"
41 #include "fits.h"
42
43 typedef struct FITSContext {
44 const AVClass *class;
45 int blank_val;
46 } FITSContext;
47
48 /**
49 * Calculate the data_min and data_max values from the data.
50 * This is called if the values are not present in the header.
51 * @param ptr8 pointer to the data
52 * @param header pointer to the header
53 * @param end pointer to end of packet
54 * @return 0 if calculated successfully otherwise AVERROR_INVALIDDATA
55 */
fill_data_min_max(const uint8_t *ptr8, FITSHeader *header, const uint8_t *end)56 static int fill_data_min_max(const uint8_t *ptr8, FITSHeader *header, const uint8_t *end)
57 {
58 uint8_t t8;
59 int16_t t16;
60 int32_t t32;
61 int64_t t64;
62 float tflt;
63 double tdbl;
64 int i, j;
65
66 header->data_min = DBL_MAX;
67 header->data_max = -DBL_MAX;
68 switch (header->bitpix) {
69 #define CASE_N(a, t, rd) \
70 case a: \
71 for (i = 0; i < header->naxisn[1]; i++) { \
72 for (j = 0; j < header->naxisn[0]; j++) { \
73 t = rd; \
74 if (!header->blank_found || t != header->blank) { \
75 if (t > header->data_max) \
76 header->data_max = t; \
77 if (t < header->data_min) \
78 header->data_min = t; \
79 } \
80 ptr8 += abs(a) >> 3; \
81 } \
82 } \
83 break
84
85 CASE_N(-64, tdbl, av_int2double(AV_RB64(ptr8)));
86 CASE_N(-32, tflt, av_int2float(AV_RB32(ptr8)));
87 CASE_N(8, t8, ptr8[0]);
88 CASE_N(16, t16, AV_RB16(ptr8));
89 CASE_N(32, t32, AV_RB32(ptr8));
90 CASE_N(64, t64, AV_RB64(ptr8));
91 default:
92 return AVERROR_INVALIDDATA;
93 }
94 return 0;
95 }
96
97 /**
98 * Read the fits header and store the values in FITSHeader pointed by header
99 * @param avctx AVCodec context
100 * @param ptr pointer to pointer to the data
101 * @param header pointer to the FITSHeader
102 * @param end pointer to end of packet
103 * @param metadata pointer to pointer to AVDictionary to store metadata
104 * @return 0 if calculated successfully otherwise AVERROR_INVALIDDATA
105 */
fits_read_header(AVCodecContext *avctx, const uint8_t **ptr, FITSHeader *header, const uint8_t *end, AVDictionary **metadata)106 static int fits_read_header(AVCodecContext *avctx, const uint8_t **ptr, FITSHeader *header,
107 const uint8_t *end, AVDictionary **metadata)
108 {
109 const uint8_t *ptr8 = *ptr;
110 int lines_read, bytes_left, i, ret;
111 size_t size;
112
113 lines_read = 1; // to account for first header line, SIMPLE or XTENSION which is not included in packet...
114 avpriv_fits_header_init(header, STATE_BITPIX);
115 do {
116 if (end - ptr8 < 80)
117 return AVERROR_INVALIDDATA;
118 ret = avpriv_fits_header_parse_line(avctx, header, ptr8, &metadata);
119 ptr8 += 80;
120 lines_read++;
121 } while (!ret);
122 if (ret < 0)
123 return ret;
124
125 bytes_left = (((lines_read + 35) / 36) * 36 - lines_read) * 80;
126 if (end - ptr8 < bytes_left)
127 return AVERROR_INVALIDDATA;
128 ptr8 += bytes_left;
129
130 if (header->rgb && (header->naxis != 3 || (header->naxisn[2] != 3 && header->naxisn[2] != 4))) {
131 av_log(avctx, AV_LOG_ERROR, "File contains RGB image but NAXIS = %d and NAXIS3 = %d\n", header->naxis, header->naxisn[2]);
132 return AVERROR_INVALIDDATA;
133 }
134
135 if (!header->rgb && header->naxis != 2) {
136 av_log(avctx, AV_LOG_ERROR, "unsupported number of dimensions, NAXIS = %d\n", header->naxis);
137 return AVERROR_INVALIDDATA;
138 }
139
140 if (header->blank_found && (header->bitpix == -32 || header->bitpix == -64)) {
141 av_log(avctx, AV_LOG_WARNING, "BLANK keyword found but BITPIX = %d\n. Ignoring BLANK", header->bitpix);
142 header->blank_found = 0;
143 }
144
145 size = abs(header->bitpix) >> 3;
146 for (i = 0; i < header->naxis; i++) {
147 if (size == 0 || header->naxisn[i] > SIZE_MAX / size) {
148 av_log(avctx, AV_LOG_ERROR, "unsupported size of FITS image");
149 return AVERROR_INVALIDDATA;
150 }
151 size *= header->naxisn[i];
152 }
153
154 if (end - ptr8 < size)
155 return AVERROR_INVALIDDATA;
156 *ptr = ptr8;
157
158 if (!header->rgb && (!header->data_min_found || !header->data_max_found)) {
159 ret = fill_data_min_max(ptr8, header, end);
160 if (ret < 0) {
161 av_log(avctx, AV_LOG_ERROR, "invalid BITPIX, %d\n", header->bitpix);
162 return ret;
163 }
164 } else {
165 /*
166 * instead of applying bscale and bzero to every element,
167 * we can do inverse transformation on data_min and data_max
168 */
169 header->data_min = (header->data_min - header->bzero) / header->bscale;
170 header->data_max = (header->data_max - header->bzero) / header->bscale;
171 }
172 if (!header->rgb && header->data_min >= header->data_max) {
173 if (header->data_min > header->data_max) {
174 av_log(avctx, AV_LOG_ERROR, "data min/max (%g %g) is invalid\n", header->data_min, header->data_max);
175 return AVERROR_INVALIDDATA;
176 }
177 av_log(avctx, AV_LOG_WARNING, "data min/max indicates a blank image\n");
178 header->data_max ++;
179 }
180
181 return 0;
182 }
183
fits_decode_frame(AVCodecContext *avctx, AVFrame *p, int *got_frame, AVPacket *avpkt)184 static int fits_decode_frame(AVCodecContext *avctx, AVFrame *p,
185 int *got_frame, AVPacket *avpkt)
186 {
187 const uint8_t *ptr8 = avpkt->data, *end;
188 uint8_t t8;
189 int16_t t16;
190 int32_t t32;
191 int64_t t64;
192 float tflt;
193 double tdbl;
194 int ret, i, j, k;
195 const int map[] = {2, 0, 1, 3}; // mapping from GBRA -> RGBA as RGBA is to be stored in FITS file..
196 uint8_t *dst8;
197 uint16_t *dst16;
198 uint64_t t;
199 FITSHeader header;
200 FITSContext * fitsctx = avctx->priv_data;
201
202 end = ptr8 + avpkt->size;
203 p->metadata = NULL;
204 ret = fits_read_header(avctx, &ptr8, &header, end, &p->metadata);
205 if (ret < 0)
206 return ret;
207
208 if (header.rgb) {
209 if (header.bitpix == 8) {
210 if (header.naxisn[2] == 3) {
211 avctx->pix_fmt = AV_PIX_FMT_GBRP;
212 } else {
213 avctx->pix_fmt = AV_PIX_FMT_GBRAP;
214 }
215 } else if (header.bitpix == 16) {
216 if (header.naxisn[2] == 3) {
217 avctx->pix_fmt = AV_PIX_FMT_GBRP16;
218 } else {
219 avctx->pix_fmt = AV_PIX_FMT_GBRAP16;
220 }
221 } else {
222 av_log(avctx, AV_LOG_ERROR, "unsupported BITPIX = %d\n", header.bitpix);
223 return AVERROR_INVALIDDATA;
224 }
225 } else {
226 if (header.bitpix == 8) {
227 avctx->pix_fmt = AV_PIX_FMT_GRAY8;
228 } else {
229 avctx->pix_fmt = AV_PIX_FMT_GRAY16;
230 }
231 }
232
233 if ((ret = ff_set_dimensions(avctx, header.naxisn[0], header.naxisn[1])) < 0)
234 return ret;
235
236 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
237 return ret;
238
239 /*
240 * FITS stores images with bottom row first. Therefore we have
241 * to fill the image from bottom to top.
242 */
243 if (header.rgb) {
244 switch(header.bitpix) {
245 #define CASE_RGB(cas, dst, type, dref) \
246 case cas: \
247 for (k = 0; k < header.naxisn[2]; k++) { \
248 for (i = 0; i < avctx->height; i++) { \
249 dst = (type *) (p->data[map[k]] + (avctx->height - i - 1) * p->linesize[map[k]]); \
250 for (j = 0; j < avctx->width; j++) { \
251 t32 = dref(ptr8); \
252 if (!header.blank_found || t32 != header.blank) { \
253 t = t32 * header.bscale + header.bzero; \
254 } else { \
255 t = fitsctx->blank_val; \
256 } \
257 *dst++ = (type) t; \
258 ptr8 += cas >> 3; \
259 } \
260 } \
261 } \
262 break
263
264 CASE_RGB(8, dst8, uint8_t, *);
265 CASE_RGB(16, dst16, uint16_t, AV_RB16);
266 }
267 } else {
268 double scale = header.data_max - header.data_min;
269
270 if (scale <= 0 || !isfinite(scale)) {
271 scale = 1;
272 }
273 scale = 1/scale;
274
275 switch (header.bitpix) {
276 #define CASE_GRAY(cas, dst, type, t, rd) \
277 case cas: \
278 for (i = 0; i < avctx->height; i++) { \
279 dst = (type *) (p->data[0] + (avctx->height-i-1)* p->linesize[0]); \
280 for (j = 0; j < avctx->width; j++) { \
281 t = rd; \
282 if (!header.blank_found || t != header.blank) { \
283 *dst++ = lrint(((t - header.data_min) * ((1 << (sizeof(type) * 8)) - 1)) * scale); \
284 } else { \
285 *dst++ = fitsctx->blank_val; \
286 } \
287 ptr8 += abs(cas) >> 3; \
288 } \
289 } \
290 break
291
292 CASE_GRAY(-64, dst16, uint16_t, tdbl, av_int2double(AV_RB64(ptr8)));
293 CASE_GRAY(-32, dst16, uint16_t, tflt, av_int2float(AV_RB32(ptr8)));
294 CASE_GRAY(8, dst8, uint8_t, t8, ptr8[0]);
295 CASE_GRAY(16, dst16, uint16_t, t16, AV_RB16(ptr8));
296 CASE_GRAY(32, dst16, uint16_t, t32, AV_RB32(ptr8));
297 CASE_GRAY(64, dst16, uint16_t, t64, AV_RB64(ptr8));
298 default:
299 av_log(avctx, AV_LOG_ERROR, "invalid BITPIX, %d\n", header.bitpix);
300 return AVERROR_INVALIDDATA;
301 }
302 }
303
304 p->key_frame = 1;
305 p->pict_type = AV_PICTURE_TYPE_I;
306
307 *got_frame = 1;
308
309 return avpkt->size;
310 }
311
312 static const AVOption fits_options[] = {
313 { "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},
314 { NULL },
315 };
316
317 static const AVClass fits_decoder_class = {
318 .class_name = "FITS decoder",
319 .item_name = av_default_item_name,
320 .option = fits_options,
321 .version = LIBAVUTIL_VERSION_INT,
322 };
323
324 const FFCodec ff_fits_decoder = {
325 .p.name = "fits",
326 .p.type = AVMEDIA_TYPE_VIDEO,
327 .p.id = AV_CODEC_ID_FITS,
328 .p.capabilities = AV_CODEC_CAP_DR1,
329 .p.long_name = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
330 .p.priv_class = &fits_decoder_class,
331 .priv_data_size = sizeof(FITSContext),
332 FF_CODEC_DECODE_CB(fits_decode_frame),
333 };
334