[FFmpeg-devel] [PATCH] Add FITS Encoder

Paras Chadha paraschadha18 at gmail.com
Sun Jul 16 15:31:20 EEST 2017


Signed-off-by: Paras Chadha <paraschadha18 at gmail.com>
---
 doc/general.texi       |   2 +
 libavcodec/Makefile    |   1 +
 libavcodec/allcodecs.c |   1 +
 libavcodec/fitsenc.c   | 238 +++++++++++++++++++++++++++++++++++++++++++++++++
 libavformat/img2enc.c  |   1 +
 5 files changed, 243 insertions(+)
 create mode 100644 libavcodec/fitsenc.c

diff --git a/doc/general.texi b/doc/general.texi
index 8f582d5..7f389ce 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -591,6 +591,8 @@ following image formats are supported:
     @tab Digital Picture Exchange
 @item EXR          @tab   @tab X
     @tab OpenEXR
+ at item FITS         @tab X @tab X
+    @tab Flexible Image Transport System
 @item JPEG         @tab X @tab X
     @tab Progressive JPEG is not supported.
 @item JPEG 2000    @tab X @tab X
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index de1187f..9ad44e0 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -291,6 +291,7 @@ OBJS-$(CONFIG_FFV1_ENCODER)            += ffv1enc.o ffv1.o
 OBJS-$(CONFIG_FFWAVESYNTH_DECODER)     += ffwavesynth.o
 OBJS-$(CONFIG_FIC_DECODER)             += fic.o
 OBJS-$(CONFIG_FITS_DECODER)            += fitsdec.o
+OBJS-$(CONFIG_FITS_ENCODER)            += fitsenc.o
 OBJS-$(CONFIG_FLAC_DECODER)            += flacdec.o flacdata.o flac.o
 OBJS-$(CONFIG_FLAC_ENCODER)            += flacenc.o flacdata.o flac.o vorbis_data.o
 OBJS-$(CONFIG_FLASHSV_DECODER)         += flashsv.o
diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
index 0243f47..d180dde 100644
--- a/libavcodec/allcodecs.c
+++ b/libavcodec/allcodecs.c
@@ -192,6 +192,7 @@ static void register_all(void)
     REGISTER_ENCDEC (FFV1,              ffv1);
     REGISTER_ENCDEC (FFVHUFF,           ffvhuff);
     REGISTER_DECODER(FIC,               fic);
+    REGISTER_ENCDEC (FITS,              fits);
     REGISTER_ENCDEC (FLASHSV,           flashsv);
     REGISTER_ENCDEC (FLASHSV2,          flashsv2);
     REGISTER_DECODER(FLIC,              flic);
diff --git a/libavcodec/fitsenc.c b/libavcodec/fitsenc.c
new file mode 100644
index 0000000..cc3fe77
--- /dev/null
+++ b/libavcodec/fitsenc.c
@@ -0,0 +1,238 @@
+/*
+ * FITS image encoder
+ * 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 encoder
+ *
+ * Specification: https://fits.gsfc.nasa.gov/fits_standard.html Version 3.0
+ *
+ * RGBA images are encoded as planes in RGBA order. So, NAXIS3 is 3 or 4 for them.
+ * Also CTYPE = 'RGB ' is added to the header to distinguish them from 3d images.
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "avcodec.h"
+#include "bytestream.h"
+#include "internal.h"
+
+typedef struct FITSContext {
+    int first_image;
+} FITSContext;
+
+static av_cold int fits_encode_init(AVCodecContext *avctx)
+{
+    FITSContext * fitsctx = avctx->priv_data;
+    fitsctx->first_image = 1;
+    return 0;
+}
+
+static int write_keyword_value(uint8_t **bytestream, const char * keyword, int value)
+{
+    int len, ret;
+    uint8_t * header = * bytestream;
+    len = strlen(keyword);
+
+    memcpy(header, keyword, len);
+    memset(header + len, ' ', 8 - len);
+    header[8] = '=';
+    header[9] = ' ';
+    header += 10;
+
+    ret = snprintf(header, 70, "%d", value);
+    memset(header + ret, ' ', 70 - ret);
+
+    *bytestream += 80;
+    return 0;
+}
+
+static int fits_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
+                            const AVFrame *pict, int *got_packet)
+{
+    AVFrame * const p = (AVFrame *)pict;
+    FITSContext * fitsctx = avctx->priv_data;
+    uint8_t *bytestream, *bytestream_start, *ptr;
+    uint64_t header_size = 2880, data_size = 0, padded_data_size = 0;
+    int ret, bitpix, naxis, naxis3 = 1, bzero = 0, i, j, k, t, rgb = 0;
+
+    switch (avctx->pix_fmt) {
+        case AV_PIX_FMT_GRAY8:
+            bitpix = 8;
+            naxis = 2;
+            break;
+        case AV_PIX_FMT_GRAY16BE:
+            bitpix = 16;
+            naxis = 2;
+            bzero = 32768;
+            break;
+        case AV_PIX_FMT_RGB24:
+        case AV_PIX_FMT_RGBA:
+            bitpix = 8;
+            naxis = 3;
+            rgb = 1;
+            if (avctx->pix_fmt == AV_PIX_FMT_RGB24) {
+                naxis3 = 3;
+            } else {
+                naxis3 = 4;
+            }
+            break;
+        case AV_PIX_FMT_RGB48BE:
+        case AV_PIX_FMT_RGBA64BE:
+            bitpix = 16;
+            naxis = 3;
+            bzero = 32768;
+            rgb = 1;
+            if (avctx->pix_fmt == AV_PIX_FMT_RGB48BE) {
+                naxis3 = 3;
+            } else {
+                naxis3 = 4;
+            }
+            break;
+        default:
+            av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
+            return AVERROR(EINVAL);
+    }
+
+    data_size = (bitpix >> 3) * avctx->height * avctx->width * naxis3;
+    padded_data_size = ((data_size + 2879) / 2880 ) * 2880;
+
+    if ((ret = ff_alloc_packet2(avctx, pkt, header_size + padded_data_size, 0)) < 0)
+        return ret;
+
+    bytestream_start =
+    bytestream       = pkt->data;
+
+    if (fitsctx->first_image) {
+        memcpy(bytestream, "SIMPLE  = ", 10);
+        memset(bytestream + 10, ' ', 70);
+        bytestream[29] = 'T';
+    } else {
+        memcpy(bytestream, "XTENSION= 'IMAGE   '", 20);
+        memset(bytestream + 20, ' ', 60);
+    }
+    bytestream += 80;
+
+    write_keyword_value(&bytestream, "BITPIX", bitpix);         // no of bits per pixel
+    write_keyword_value(&bytestream, "NAXIS", naxis);           // no of dimensions of image
+    write_keyword_value(&bytestream, "NAXIS1", avctx->width);   // first dimension i.e. width
+    write_keyword_value(&bytestream, "NAXIS2", avctx->height);  // second dimension i.e. height
+
+    if (rgb)
+        write_keyword_value(&bytestream, "NAXIS3", naxis3);     // third dimension to store RGBA planes
+
+    if (!fitsctx->first_image) {
+        write_keyword_value(&bytestream, "PCOUNT", 0);
+        write_keyword_value(&bytestream, "GCOUNT", 1);
+    } else {
+        fitsctx->first_image = 0;
+    }
+
+    /*
+     * Since FITS does not support unsigned 16 bit integers,
+     * BZERO = 32768 is used to store unsigned 16 bit integers as
+     * signed integers so that it can be read properly.
+     */
+    if (bitpix == 16)
+        write_keyword_value(&bytestream, "BZERO", bzero);
+
+    if (rgb) {
+        memcpy(bytestream, "CTYPE3  = 'RGB     '", 20);
+        memset(bytestream + 20, ' ', 60);
+        bytestream += 80;
+    }
+
+    memcpy(bytestream, "END", 3);
+    memset(bytestream + 3, ' ', 77);
+    bytestream += 80;
+
+    t = header_size - (bytestream - bytestream_start);
+    memset(bytestream, ' ', t);
+    bytestream += t;
+
+    if (rgb) {
+        switch (avctx->pix_fmt) {
+            case AV_PIX_FMT_RGB24:
+            case AV_PIX_FMT_RGBA:
+                for (k = 0; k < naxis3; k++) {
+                    for (i = 0; i < avctx->height; i++) {
+                        ptr = p->data[0] + (avctx->height - i - 1) * p->linesize[0] + k;
+                        for (j = 0; j < avctx->width; j++) {
+                            bytestream_put_byte(&bytestream, ptr[0]);
+                            ptr += naxis3;
+                        }
+                    }
+                }
+                break;
+            case AV_PIX_FMT_RGB48BE:
+            case AV_PIX_FMT_RGBA64BE:
+                for (k = 0; k < naxis3; k++) {
+                    for (i = 0; i < avctx->height; i++) {
+                        ptr = p->data[0] + (avctx->height - i - 1) * p->linesize[0] + k * 2;
+                        for (j = 0; j < avctx->width; j++) {
+                            bytestream_put_be16(&bytestream, AV_RB16(ptr) - bzero);
+                            ptr += naxis3 * 2;
+                        }
+                    }
+                }
+                break;
+        }
+    } else {
+        for (i = 0; i < avctx->height; i++) {
+            ptr = p->data[0] + (avctx->height - i - 1) * p->linesize[0];
+            if (bitpix == 16) {
+                for (j = 0; j < avctx->width; j++) {
+                    bytestream_put_be16(&bytestream, AV_RB16(ptr) - bzero);
+                    ptr += 2;
+                }
+            } else {
+                memcpy(bytestream, ptr, avctx->width);
+                bytestream += avctx->width;
+            }
+        }
+    }
+
+    t = padded_data_size - data_size;
+    memset(bytestream, 0, t);
+    bytestream += t;
+
+    pkt->size   = bytestream - bytestream_start;
+    pkt->flags |= AV_PKT_FLAG_KEY;
+    *got_packet = 1;
+
+    return 0;
+}
+
+AVCodec ff_fits_encoder = {
+    .name           = "fits",
+    .long_name      = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_FITS,
+    .priv_data_size = sizeof(FITSContext),
+    .init           = fits_encode_init,
+    .encode2        = fits_encode_frame,
+    .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_RGBA64BE,
+                                                 AV_PIX_FMT_RGB48BE,
+                                                 AV_PIX_FMT_RGBA,
+                                                 AV_PIX_FMT_RGB24,
+                                                 AV_PIX_FMT_GRAY16BE,
+                                                 AV_PIX_FMT_GRAY8,
+                                                 AV_PIX_FMT_NONE },
+};
diff --git a/libavformat/img2enc.c b/libavformat/img2enc.c
index 1297b1a..25283cc 100644
--- a/libavformat/img2enc.c
+++ b/libavformat/img2enc.c
@@ -237,6 +237,7 @@ AVOutputFormat ff_image2_muxer = {
 AVOutputFormat ff_image2pipe_muxer = {
     .name           = "image2pipe",
     .long_name      = NULL_IF_CONFIG_SMALL("piped image2 sequence"),
+    .extensions     = "fits",
     .priv_data_size = sizeof(VideoMuxData),
     .video_codec    = AV_CODEC_ID_MJPEG,
     .write_header   = write_header,
-- 
2.4.11



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