1 /*
2 * FITS image encoder
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 encoder
25 *
26 * Specification: https://fits.gsfc.nasa.gov/fits_standard.html Version 3.0
27 *
28 * RGBA images are encoded as planes in RGBA order. So, NAXIS3 is 3 or 4 for them.
29 * Also CTYPE3 = 'RGB ' is added to the header to distinguish them from 3d images.
30 */
31
32 #include "libavutil/intreadwrite.h"
33 #include "avcodec.h"
34 #include "bytestream.h"
35 #include "codec_internal.h"
36 #include "encode.h"
37
fits_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet)38 static int fits_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
39 const AVFrame *pict, int *got_packet)
40 {
41 AVFrame * const p = (AVFrame *)pict;
42 uint8_t *bytestream, *ptr;
43 const uint16_t flip = (1 << 15);
44 uint64_t data_size = 0, padded_data_size = 0;
45 int ret, bitpix, naxis3 = 1, i, j, k, bytes_left;
46 int map[] = {2, 0, 1, 3}; // mapping from GBRA -> RGBA as RGBA is to be stored in FITS file..
47
48 switch (avctx->pix_fmt) {
49 case AV_PIX_FMT_GRAY8:
50 case AV_PIX_FMT_GRAY16BE:
51 map[0] = 0; // grayscale images should be directly mapped
52 if (avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
53 bitpix = 8;
54 } else {
55 bitpix = 16;
56 }
57 break;
58 case AV_PIX_FMT_GBRP:
59 case AV_PIX_FMT_GBRAP:
60 bitpix = 8;
61 if (avctx->pix_fmt == AV_PIX_FMT_GBRP) {
62 naxis3 = 3;
63 } else {
64 naxis3 = 4;
65 }
66 break;
67 case AV_PIX_FMT_GBRP16BE:
68 case AV_PIX_FMT_GBRAP16BE:
69 bitpix = 16;
70 if (avctx->pix_fmt == AV_PIX_FMT_GBRP16BE) {
71 naxis3 = 3;
72 } else {
73 naxis3 = 4;
74 }
75 break;
76 default:
77 av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
78 return AVERROR(EINVAL);
79 }
80
81 data_size = (bitpix >> 3) * avctx->height * avctx->width * naxis3;
82 padded_data_size = ((data_size + 2879) / 2880 ) * 2880;
83
84 if ((ret = ff_get_encode_buffer(avctx, pkt, padded_data_size, 0)) < 0)
85 return ret;
86
87 bytestream = pkt->data;
88
89 for (k = 0; k < naxis3; k++) {
90 for (i = 0; i < avctx->height; i++) {
91 ptr = p->data[map[k]] + (avctx->height - i - 1) * p->linesize[map[k]];
92 if (bitpix == 16) {
93 for (j = 0; j < avctx->width; j++) {
94 // subtracting bzero is equivalent to first bit flip
95 bytestream_put_be16(&bytestream, AV_RB16(ptr) ^ flip);
96 ptr += 2;
97 }
98 } else {
99 memcpy(bytestream, ptr, avctx->width);
100 bytestream += avctx->width;
101 }
102 }
103 }
104
105 bytes_left = padded_data_size - data_size;
106 memset(bytestream, 0, bytes_left);
107
108 *got_packet = 1;
109
110 return 0;
111 }
112
113 const FFCodec ff_fits_encoder = {
114 .p.name = "fits",
115 .p.long_name = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
116 .p.type = AVMEDIA_TYPE_VIDEO,
117 .p.id = AV_CODEC_ID_FITS,
118 .p.capabilities = AV_CODEC_CAP_DR1,
119 FF_CODEC_ENCODE_CB(fits_encode_frame),
120 .p.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_GBRAP16BE,
121 AV_PIX_FMT_GBRP16BE,
122 AV_PIX_FMT_GBRP,
123 AV_PIX_FMT_GBRAP,
124 AV_PIX_FMT_GRAY16BE,
125 AV_PIX_FMT_GRAY8,
126 AV_PIX_FMT_NONE },
127 };
128