On Fri, Jul 14, 2017 at 11:15 PM, Nicolas George <geo...@nsup.org> wrote:
> Le tridi 23 messidor, an CCXXV, Paras Chadha a écrit : > > Hi, I have attached the dump of a FITS File containing 5 images and 4 > > binary table xtensions. The dump is taken using fdump utility. Please > take > > a look. > > Thanks for the dump. But it is you who know the format, thus it is you > who can tell the most accurate things about it. > > Anyway, distributing the task between the demuxer and the decoder and > deciding the format of the payload is absolutely necessary before any > real work can proceed on the implementation. > > > > This is the header of the first (primary) image. > > > > SIMPLE = T / FITS STANDARD > > BITPIX = 8 / Character information > > NAXIS = 0 / No image data array present > > EXTEND = T / There may be standard extensions > > DATE = '21/09/99' / Date file was written (dd/mm/yy) 19yy > > ORIGIN = 'CEA/SSL UC Berkeley' / EUVE Science Archive > > CREATOR = 'STWFITS ' / Fitsio version 05-Aug-1997 > > TELESCOP= 'EUVE ' / Extreme Ultraviolet Explorer > > INSTTYPE= 'DS/S ' / Instrument type (DS/S, SCANNER) > > OBJECT = ' ' / Name of observed object > > RA_OBJ = 79.17265 / R.A. of the object (degrees) > > DEC_OBJ = 45.99862 / Declination of the object (degrees) > > RA_PNT = 79.1724000000003 / R.A. of the pointing direction (degrees) > > DEC_PNT = 46.007 / Declination of the pointing direction > (degrees) > > RA_PROC = 79.17586 / R.A. used to process data (degrees) > > DEC_PROC= 45.99578 / Declination used to process data > (degrees) > > DATE-OBS= '08/09/99 GMT' / Start date of observation (dd/mm/yy) > 19yy > > TIME-OBS= '00:14:29 GMT' / Start time of observation (hh:mm:ss GMT) > > DATE-END= '13/09/99 GMT' / End date of observation (dd/mm/yy) 19yy > > TIME-END= '22:07:43 GMT' / End time of observation (hh:mm:ss GMT) > > OBS_MODE= 'POINTING' / Inertial pointing mode > > DITHER = 'SPIRAL ' / Spacecraft dither type (DITHERED, > SPIRAL, NONE) > > DETMODE = 'WSZ ' / Detector position conversion mode (WSZ > or XY) > > OFF-AXIS= F / Was this pointing done off-axis > > MOVING = F / Did the source position vary during > observation > > DAYNIGHT= 'NIGHT ' / Day/night data indicator (DAY, NIGHT, > BOTH) > > VALIDTIM= 132369.40583229 / Amount of telemetry present (seconds) > > RA_UNIT = 'deg ' / Units for Right Ascension > > DEC_UNIT= 'deg ' / Units for Declination > > EQUINOX = 2000. / Coordinate equinox > > RADECSYS= 'FK5 ' / Frame of reference of coordinates > > TIMESYS = 'MJD ' / MJD = JD - 2400000.5 > > TIMEZERO= 0. / No time offset required for EUVE event > times > > TIMEUNIT= 's ' / Units for TSTART, TSTOP, TIMEZERO > > CLOCKCOR= 'NO ' / Not corrected to UT > > TIMEREF = 'LOCAL ' / No corrections applied (barycentric, > etc.) > > TASSIGN = 'SATELLITE' / Event times are assigned at the > satellite > > TSTART = 987466469.376002 / Time of start of observation (seconds) > > TSTOP = 987977263.104001 / Time of end of observation (seconds) > > MJDREF = 40000. / MJD of SC clock start, 24.00 May 1968 > > EGOCSVER= 'egocs1.7.2' / Software version used to produce this > data > > REFVERS = 'egodata1.15.2' / Reference calibration dataset version > used > > COMMENT ' ' > > COMMENT 'This file is part of the EUVE Science Archive. It contains' > > COMMENT 'images and filter limits for one EUVE observation.' > > COMMENT ' ' > > COMMENT 'The EUVE Science Archive contains the science data from' > > COMMENT 'observations performed with the EUVE telescopes. It forms > one' > > COMMENT 'part of the EUVE Permanent Archive. The other part of the' > > COMMENT 'permanent archive is the EUVE Telemetry Archive, which is a' > > COMMENT 'complete record of the raw telemetry from the EUVE mission.' > > COMMENT ' ' > > COMMENT 'For documentation of the contents of the EUVE Science > Archive,' > > COMMENT 'see the "EUVE Science Archive User's Guide". The contents > of' > > COMMENT 'the EUVE Telemetry Archive are described in the "EUVE' > > COMMENT 'Telemetry Archive User's Guide".' > > COMMENT ' ' > > COMMENT 'The EUVE Permanent Archive was produced by the Center for > EUV' > > COMMENT 'Astrophysics, a division of UC Berkeley's Space Science' > > COMMENT Laboratory. > > COMMENT ' ' > > END > > > > This will be followed by the data part whose size (in bits) is given by > - |BITPIX| * GCOUNT * (PCOUNT + NAXIS1 * NAXIS2 * ... * NAXISm) = 0 in this > case, so no data part is there > > You forgot to explain what should be done with an image without data. > Image without data means that there is no image. It is just the header which can be ignored. So, currently i am skipping over the header if it contains no image. > > > > > This is the header of second image. > > > > XTENSION= 'IMAGE ' / IMAGE extension > > BITPIX = 16 / 8-bit bytes > > NAXIS = 2 / 2-dimensional image > > NAXIS1 = 2048 / Number of image columns > > NAXIS2 = 2048 / Number of image rows > > PCOUNT = 0 / Size of special data area > > GCOUNT = 1 / Only one group > > EXTNAME = 'ds ' / Name of image > > BSCALE = 1.0E0 / Scale factor for pixel values > > BZERO = 0.0E0 / Offset for pixel values > > CTYPE1 = 'RA---TAN' / RA in tangent plane projection > > CRVAL1 = 79.1726455688478 / RA at reference pixel > > CRPIX1 = 1024.5 / reference pixel, axis 1 > > CDELT1 = 0.00126953120343387 / scale, axis 1 > > CUNIT1 = 'deg ' / units of CRVAL1, CDELT1 > > CTYPE2 = 'DEC--TAN' / DEC in tangent plane projection > > CRVAL2 = 45.9986228942872 / DEC at reference pixel > > CRPIX2 = 1024.5 / reference pixel, axis 2 > > CDELT2 = 0.00126953120343387 / scale, axis 2 > > CUNIT2 = 'deg ' / units of CRVAL2, CDELT2 > > EXPTIME = 64971.06 / Primbsch/deadtime corrected exposure > time > > RAWEXP = 86784.98 / Uncorrected exposure time > > FILENAME= 'ds ' > > ORIGIN = 'CEA/SSL UC Berkeley' / EUVE Science Archive > > CREATOR = 'STWFITS ' / Fitsio version 05-Aug-1997 > > TELESCOP= 'EUVE ' / Extreme Ultraviolet Explorer > > INSTTYPE= 'DS/S ' / Instrument type (DS/S, SCANNER) > > INSTRUME= 'DS/S ' / Deep Survey - Spectrometer > > DETNAM = 'DS ' / Deep Survey > > OBJECT = ' ' / Name of observed object > > RA_OBJ = '79.172646' / R.A. of the object (degrees) > > DEC_OBJ = '45.998624' / Declination of the object (degrees) > > RA_PNT = 79.1724000000002 / R.A. of the pointing direction (degrees) > > DEC_PNT = 46.007 / Declination of the pointing direction > (degrees) > > RA_PROC = 79.17586 / R.A. used to process data (degrees) > > DEC_PROC= 45.99578 / Declination used to process data > (degrees) > > DATE-OBS= '08/09/99 GMT' / Start date of observation (dd/mm/yy) > 19yy > > TIME-OBS= '00:14:29 GMT' / Start time of observation (hh:mm:ss GMT) > > DATE-END= '13/09/99 GMT' / End date of observation (dd/mm/yy) 19yy > > TIME-END= '22:07:43 GMT' / End time of observation (hh:mm:ss GMT) > > OBS_MODE= 'POINTING' / Inertial pointing mode > > DITHER = 'SPIRAL ' / Spacecraft dither type (DITHERED, > SPIRAL, NONE) > > DETMODE = 'WSZ ' / Detector position conversion mode (WSZ > or XY) > > OFF-AXIS= F / Was this pointing done off-axis > > MOVING = F / Did the source position vary during > observation > > DAYNIGHT= 'NIGHT ' / Day/night data indicator (DAY, NIGHT, > BOTH) > > VALIDTIM= 132369.40583229 / Amount of telemetry present (seconds) > > RA_UNIT = 'deg ' / Units for Right Ascension > > DEC_UNIT= 'deg ' / Units for Declination > > EQUINOX = 2000. / Coordinate equinox > > RADECSYS= 'FK5 ' / Frame of reference of coordinates > > TIMESYS = 'MJD ' / MJD = JD - 2400000.5 > > TIMEZERO= 0. / No time offset required for EUVE event > times > > TIMEUNIT= 's ' / Units for TSTART, TSTOP, TIMEZERO > > CLOCKCOR= 'NO ' / Not corrected to UT > > TIMEREF = 'LOCAL ' / No corrections applied (barycentric, > etc.) > > TASSIGN = 'SATELLITE' / Event times are assigned at the > satellite > > TSTART = 987466469.376001 / Time of start of observation (seconds) > > TSTOP = 987977263.104001 / Time of end of observation (seconds) > > TIERRABS= 0.001 / Timing precision (seconds) > > MJDREF = 40000. / MJD of SC clock start, 24.00 May 1968 > > EGOCSVER= 'egocs1.7.2' / Software version used to produce this > data > > REFVERS = 'egodata1.15.2' / Reference calibration dataset version > used > > INHERIT = F / Do not inherit cards from the primary > header > > COMMENT ' ' > > COMMENT 'This extension contains an image of the Deep Survey > detector' > > COMMENT 'for this observation. All events have been remapped onto > the' > > COMMENT 'sky. The filter limits used to select events for inclusion' > > COMMENT 'in this image are in the binary table extension named' > > COMMENT '"ds_limits" in this file.' > > COMMENT ' ' > > END > > > > Here also there is data part whose size is given by the same expression > > At a guess, all this could be parsed by the demuxer, using BITPIX and > NAXIS* to populate codecpar->width, codecpar->height and > codecpar->format and putting all the rest in string metadata, and only > the data itself go in the packet payload. > Okay, i can fill height, width and format in demuxer itself. By metadata above, do you mean AVStream meatdata ? Actually i need BLANK, BSCALE, BZERO, DATAMIN and DATAMIN keywords in the decoder to decode the image correctly. How can i access them there ? > > But you probably know better, so please have a loot at the fields in > AVPacket and AVCodecParameters, and tell us what you think. > > Regards, > > -- > Nicolas George > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > -- Have a Nice Day ! _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
