fitsdec.c File Reference

FITS image decoder. More...

#include "avcodec.h"
#include "internal.h"
#include <float.h>
#include "libavutil/intreadwrite.h"
#include "libavutil/intfloat.h"
#include "libavutil/dict.h"
#include "libavutil/opt.h"
#include "fits.h"

Go to the source code of this file.

Data Structures
struct	FITSContext

Macros
#define	CASE_N(a, t, rd)
#define	CASE_RGB(cas, dst, type, dref)
#define	CASE_GRAY(cas, dst, type, t, rd)

Functions
static int	fill_data_min_max (const uint8_t *ptr8, FITSHeader *header, const uint8_t *end)
	Calculate the data_min and data_max values from the data. More...
static int	fits_read_header (AVCodecContext *avctx, const uint8_t **ptr, FITSHeader *header, const uint8_t *end, AVDictionary **metadata)
	Read the fits header and store the values in FITSHeader pointed by header. More...
static int	fits_decode_frame (AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)

Variables
static const AVOption	fits_options []
static const AVClass	fits_decoder_class
AVCodec	ff_fits_decoder

Detailed Description

FITS image decoder.

Specification: https://fits.gsfc.nasa.gov/fits_standard.html Version 3.0

Support all 2d images alongwith, bzero, bscale and blank keywords. RGBA images are supported as NAXIS3 = 3 or 4 i.e. Planes in RGBA order. Also CTYPE = 'RGB ' should be present. Also to interpret data, values are linearly scaled using min-max scaling but not RGB images.

Definition in file fitsdec.c.

Macro Definition Documentation

CASE_N

#define CASE_N	(		a,
			t,
			rd
	)

Value:

case a: \
        for (i = 0; i < header->naxisn[1]; i++) { \
            for (j = 0; j < header->naxisn[0]; j++) { \
                t = rd; \
                if (!header->blank_found || t != header->blank) { \
                    if (t > header->data_max) \
                        header->data_max = t; \
                    if (t < header->data_min) \
                        header->data_min = t; \
                } \
                ptr8 += abs(a) >> 3; \
            } \
        } \
        break

Referenced by fill_data_min_max().

CASE_RGB

#define CASE_RGB	(		cas,
			dst,
			type,
			dref
	)

Value:

case cas: \
        for (k = 0; k < header.naxisn[2]; k++) { \
            for (i = 0; i < avctx->height; i++) { \
                dst = (type *) (p->data[map[k]] + (avctx->height - i - 1) * p->linesize[map[k]]); \
                for (j = 0; j < avctx->width; j++) { \
                    t32 = dref(ptr8); \
                    if (!header.blank_found || t32 != header.blank) { \
                        t = t32 * header.bscale + header.bzero; \
                    } else { \
                        t = fitsctx->blank_val; \
                    } \
                    *dst++ = (type) t; \
                    ptr8 += cas >> 3; \
                } \
            } \
        } \
        break

Referenced by fits_decode_frame().

CASE_GRAY

#define CASE_GRAY	(		cas,
			dst,
			type,
			t,
			rd
	)

Value:

case cas: \
        for (i = 0; i < avctx->height; i++) { \
            dst = (type *) (p->data[0] + (avctx->height-i-1)* p->linesize[0]); \
            for (j = 0; j < avctx->width; j++) { \
                t = rd; \
                if (!header.blank_found || t != header.blank) { \
                    *dst++ = ((t - header.data_min) * ((1 << (sizeof(type) * 8)) - 1)) / (header.data_max - header.data_min); \
                } else { \
                    *dst++ = fitsctx->blank_val; \
                } \
                ptr8 += abs(cas) >> 3; \
            } \
        } \
        break

Referenced by fits_decode_frame().

Function Documentation

fill_data_min_max()

static int fill_data_min_max ( const uint8_t *  ptr8, FITSHeader *  header, const uint8_t *  end  )

static

Calculate the data_min and data_max values from the data.

This is called if the values are not present in the header.

Parameters

ptr8	pointer to the data
header	pointer to the header
end	pointer to end of packet

Returns

0 if calculated successfully otherwise AVERROR_INVALIDDATA

Definition at line 55 of file fitsdec.c.

Referenced by fits_read_header().

fits_read_header()

static int fits_read_header ( AVCodecContext *  avctx, const uint8_t **  ptr, FITSHeader *  header, const uint8_t *  end, AVDictionary **  metadata  )

static

Read the fits header and store the values in FITSHeader pointed by header.

Parameters

avctx	AVCodec context
ptr	pointer to pointer to the data
header	pointer to the FITSHeader
end	pointer to end of packet
metadata	pointer to pointer to AVDictionary to store metadata

Returns

0 if calculated successfully otherwise AVERROR_INVALIDDATA

Definition at line 105 of file fitsdec.c.

Referenced by fits_decode_frame().

fits_decode_frame()

static int fits_decode_frame ( AVCodecContext *  avctx, void *  data, int *  got_frame, AVPacket *  avpkt  )

static

Definition at line 175 of file fitsdec.c.

Variable Documentation

fits_options

const AVOption fits_options[]

static

Initial value:

= {
    { "blank_value", "value that is used to replace BLANK pixels in data array", 0x42, AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 65535, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM},
    { NULL },
}

Definition at line 296 of file fitsdec.c.

fits_decoder_class

const AVClass fits_decoder_class

static

Initial value:

= {
    .class_name = "FITS decoder",
    .item_name  = av_default_item_name,
    .option     = fits_options,
    .version    = LIBAVUTIL_VERSION_INT,
}

Definition at line 301 of file fitsdec.c.

ff_fits_decoder

AVCodec ff_fits_decoder

Initial value:

= {
    .name           = "fits",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_FITS,
    .priv_data_size = sizeof(FITSContext),
    .decode         = fits_decode_frame,
    .capabilities   = AV_CODEC_CAP_DR1,
    .long_name      = NULL_IF_CONFIG_SMALL("Flexible Image Transport System"),
    .priv_class     = &fits_decoder_class
}

Definition at line 308 of file fitsdec.c.