Add FITS Demuxer

Signed-off-by: Paras Chadha <paraschadha18@gmail.com>

1 files changed, 231 insertions, 0 deletions

diff --git a/libavformat/fitsdec.c b/libavformat/fitsdec.c
new file mode 100644
index 0000000000..4b288b3903
--- /dev/null
+++ b/libavformat/fitsdec.c
@@ -0,0 +1,231 @@
+/*
+ * FITS demuxer
+ * 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 demuxer.
+ */
+
+#include "libavutil/intreadwrite.h"
+#include "internal.h"
+#include "libavutil/opt.h"
+#include "libavcodec/fits.h"
+#include "libavutil/bprint.h"
+
+#define FITS_BLOCK_SIZE 2880
+
+typedef struct FITSContext {
+    const AVClass *class;
+    AVRational framerate;
+    int first_image;
+    int64_t pts;
+} FITSContext;
+
+static int fits_probe(AVProbeData *p)
+{
+    const uint8_t *b = p->buf;
+    if (!memcmp(b, "SIMPLE  =                    T", 30))
+        return AVPROBE_SCORE_MAX - 1;
+    return 0;
+}
+
+static int fits_read_header(AVFormatContext *s)
+{
+    AVStream *st;
+    FITSContext * fits = s->priv_data;
+
+    st = avformat_new_stream(s, NULL);
+    if (!st)
+        return AVERROR(ENOMEM);
+
+    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
+    st->codecpar->codec_id = AV_CODEC_ID_FITS;
+
+    avpriv_set_pts_info(st, 64, fits->framerate.den, fits->framerate.num);
+    fits->pts = 0;
+    fits->first_image = 1;
+    return 0;
+}
+
+/**
+ * Parses header and checks that the current HDU contains image or not
+ * It also stores the header in the avbuf and stores the size of data part in data_size
+ * @param s pointer to AVFormat Context
+ * @param fits pointer to FITSContext
+ * @param header pointer to FITSHeader
+ * @param avbuf pointer to AVBPrint to store the header
+ * @param data_size to store the size of data part
+ * @return 1 if image found, 0 if any other extension and AVERROR_INVALIDDATA otherwise
+ */
+static int64_t is_image(AVFormatContext *s, FITSContext *fits, FITSHeader *header,
+                         AVBPrint *avbuf, uint64_t *data_size)
+{
+    int i, ret, image = 0;
+    char buf[FITS_BLOCK_SIZE] = { 0 };
+    int64_t buf_size = 0, size = 0, t;
+
+    do {
+        ret = avio_read(s->pb, buf, FITS_BLOCK_SIZE);
+        if (ret < 0) {
+            return ret;
+        } else if (ret < FITS_BLOCK_SIZE) {
+            return AVERROR_INVALIDDATA;
+        }
+
+        av_bprint_append_data(avbuf, buf, FITS_BLOCK_SIZE);
+        ret = 0;
+        buf_size = 0;
+        while(!ret && buf_size < FITS_BLOCK_SIZE) {
+            ret = avpriv_fits_header_parse_line(s, header, buf + buf_size, NULL);
+            buf_size += 80;
+        }
+    } while (!ret);
+    if (ret < 0)
+        return ret;
+
+    image = fits->first_image || header->image_extension;
+    fits->first_image = 0;
+
+    if (header->groups) {
+        image = 0;
+        if (header->naxis > 1)
+            size = 1;
+    } else if (header->naxis) {
+        size = header->naxisn[0];
+    } else {
+        image = 0;
+    }
+
+    for (i = 1; i < header->naxis; i++) {
+        if(size && header->naxisn[i] > UINT64_MAX / size)
+            return AVERROR_INVALIDDATA;
+        size *= header->naxisn[i];
+    }
+
+    if(header->pcount > UINT64_MAX - size)
+        return AVERROR_INVALIDDATA;
+    size += header->pcount;
+
+    t = (abs(header->bitpix) >> 3) * ((int64_t) header->gcount);
+    if(size && t > UINT64_MAX / size)
+        return AVERROR_INVALIDDATA;
+    size *= t;
+
+    if (!size) {
+        image = 0;
+    } else {
+        if(FITS_BLOCK_SIZE - 1 > UINT64_MAX - size)
+            return AVERROR_INVALIDDATA;
+        size = ((size + FITS_BLOCK_SIZE - 1) / FITS_BLOCK_SIZE) * FITS_BLOCK_SIZE;
+    }
+    *data_size = size;
+    return image;
+}
+
+static int fits_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    int64_t pos, ret;
+    uint64_t size;
+    FITSContext *fits = s->priv_data;
+    FITSHeader header;
+    AVBPrint avbuf;
+    char *buf;
+
+    if (fits->first_image) {
+        avpriv_fits_header_init(&header, STATE_SIMPLE);
+    } else {
+        avpriv_fits_header_init(&header, STATE_XTENSION);
+    }
+
+    av_bprint_init(&avbuf, FITS_BLOCK_SIZE, AV_BPRINT_SIZE_UNLIMITED);
+    while ((ret = is_image(s, fits, &header, &avbuf, &size)) == 0) {
+        pos = avio_skip(s->pb, size);
+        if (pos < 0)
+            return pos;
+
+        av_bprint_finalize(&avbuf, NULL);
+        av_bprint_init(&avbuf, FITS_BLOCK_SIZE, AV_BPRINT_SIZE_UNLIMITED);
+        avpriv_fits_header_init(&header, STATE_XTENSION);
+    }
+    if (ret < 0)
+        goto fail;
+
+    if (!av_bprint_is_complete(&avbuf)) {
+        ret = AVERROR(ENOMEM);
+        goto fail;
+    }
+
+    // Header is sent with the first line removed...
+    ret = av_new_packet(pkt, avbuf.len - 80 + size);
+    if (ret < 0)
+        goto fail;
+
+    pkt->stream_index = 0;
+    pkt->flags |= AV_PKT_FLAG_KEY;
+
+    ret = av_bprint_finalize(&avbuf, &buf);
+    if (ret < 0) {
+        av_packet_unref(pkt);
+        return ret;
+    }
+
+    memcpy(pkt->data, buf + 80, avbuf.len - 80);
+    pkt->size = avbuf.len - 80;
+    av_freep(&buf);
+    ret = avio_read(s->pb, pkt->data + pkt->size, size);
+    if (ret < 0) {
+        av_packet_unref(pkt);
+        return ret;
+    }
+
+    pkt->size += ret;
+    pkt->pts = fits->pts;
+    fits->pts++;
+
+    return 0;
+
+fail:
+    av_bprint_finalize(&avbuf, NULL);
+    return ret;
+}
+
+static const AVOption fits_options[] = {
+    { "framerate", "set the framerate", offsetof(FITSContext, framerate), AV_OPT_TYPE_VIDEO_RATE, {.str = "1"}, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM},
+    { NULL },
+};
+
+static const AVClass fits_demuxer_class = {
+    .class_name = "FITS demuxer",
+    .item_name  = av_default_item_name,
+    .option     = fits_options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVInputFormat ff_fits_demuxer = {
+    .name           = "fits",
+    .long_name      = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
+    .priv_data_size = sizeof(FITSContext),
+    .read_probe     = fits_probe,
+    .read_header    = fits_read_header,
+    .read_packet    = fits_read_packet,
+    .priv_class     = &fits_demuxer_class,
+    .raw_codec_id   = AV_CODEC_ID_FITS,
+};