예제 #1
0
    def __parseIFDs(self, base, start, end, IFD=""):
        assert IFD != ""
        log("Enter", "[%s]" % (IFD), "add")

        if not self._file:
            assert False
        entries = getBytes2(self._file, self._orderAPP1)
        log("Number of entries = %d" % (entries))

        for idx in xrange(entries):
            tag = getBytes2(self._file, self._orderAPP1)
            dataFormat = getBytes2(self._file, self._orderAPP1)
            numOfComps = getBytes4(self._file, self._orderAPP1)
            posBeforeDataOffset = nowAt(self._file)
            dataOffset = getBytes4(self._file, self._orderAPP1)
            posAfterDataOffset = nowAt(self._file)

            if 0 == dataFormat or dataFormat >= len(EXIF_TIFF_DATAFORMAT_LIST):
                assert False, "dataformat incorrect = %d" % (dataFormat)
                continue
            bytesPerComp = EXIF_TIFF_DATAFORMAT_LIST[dataFormat]
            dataSize = bytesPerComp * numOfComps
            if dataSize > 4:
                targetOffset = base + dataOffset
                if targetOffset <= start or targetOffset >= end:
                    continue
                else:
                    seekTo(self._file, targetOffset)
            else:
                seekTo(self._file, posBeforeDataOffset)
            entry = self.__getDataFromFormat(tag, dataFormat, dataSize)
            seekTo(self._file, posAfterDataOffset)

        log("Leave", "[%s]" % (IFD), "remove")
    def __parseIFDs(self, base, start, end, IFD=""):
        assert IFD != ""
        log("Enter", "[%s]"%(IFD), "add")

        if not self._file:
            assert False
        entries = getBytes2(self._file, self._orderAPP1)
        log("Number of entries = %d"%(entries))

        for idx in xrange(entries):
            tag = getBytes2(self._file, self._orderAPP1)
            dataFormat = getBytes2(self._file, self._orderAPP1)
            numOfComps = getBytes4(self._file, self._orderAPP1)
            posBeforeDataOffset = nowAt(self._file)
            dataOffset = getBytes4(self._file, self._orderAPP1)
            posAfterDataOffset = nowAt(self._file)

            if 0 == dataFormat or dataFormat >= len(EXIF_TIFF_DATAFORMAT_LIST):
                assert False, "dataformat incorrect = %d"%(dataFormat)
                continue
            bytesPerComp = EXIF_TIFF_DATAFORMAT_LIST[dataFormat]
            dataSize = bytesPerComp * numOfComps
            if dataSize > 4:
                targetOffset = base + dataOffset
                if targetOffset <= start or targetOffset >= end:
                    continue
                else:
                    seekTo(self._file, targetOffset)
            else:
                seekTo(self._file, posBeforeDataOffset)
            entry = self.__getDataFromFormat(tag, dataFormat, dataSize)
            seekTo(self._file, posAfterDataOffset)

        log("Leave", "[%s]"%(IFD), "remove")
예제 #3
0
    def parse(self, filePath):
        self._file = open(filePath)
        seekTo(self._file, 0)
        first = getCharToOrd(self._file)
        marker = getCharToOrd(self._file)
        if (first != 0xff or marker != JPEG_SOI):
            assert False, "Not in JPEG format !!"

        while (marker):
            first = getCharToOrd(self._file)
            if first != 0xff or first < 0:
                break
            marker = getCharToOrd(self._file)
            log("%s-%s" % (hex(first), hex(marker)))
            length = getBytes2(self._file)
            curPos = nowAt(self._file)
            log("length= %d, curPos=%d" % (length, curPos))

            if marker in [JPEG_EOI, JPEG_SOS]:
                log("EOI or SOS ... exit parsing")
                break
            elif marker == JPEG_APP0:
                log("Enter", "[APP0]", "add")
                log("Leave", "[APP0]", "remove")
                pass  # TBD
            elif marker == JPEG_APP1:
                log("Enter", "[APP1]", "add")
                header = getChar(self._file, 4)
                log("header = %s" % (header))
                if header.lower() == 'exif':
                    self.__parseAPP1(curPos + 6, curPos, curPos + length - 2)
                elif header.lower() == 'http':
                    seekTo(self._file, curPos)
                    xmpBuffer = getChar(self._file, length)
                    checkURL = "http://ns.adobe.com/xap/1.0/"
                    if xmpBuffer.startswith(checkURL):
                        headLen = len(checkURL)
                        self.__parseXMP(xmpBuffer[headLen:], length - headLen)
                    pass
                log("Leave", "[APP1]", "remove")

            elif marker == JPEG_APP2:
                log("Enter", "[APP2]", "add")
                self.__parseAPP2(length)
                log("Leave", "[APP2]", "remove")
                pass  # TBD
            elif marker == JPEG_APP13:
                log("Enter", "[APP13]", "add")
                log("Leave", "[APP13]", "remove")
                pass  # TBD
            seekTo(self._file, curPos + length - 2)
    def parse(self, filePath):
        self._file = open(filePath)
        seekTo(self._file, 0)
        first = getCharToOrd(self._file)
        marker = getCharToOrd(self._file)
        if (first != 0xff or marker != JPEG_SOI):
            assert False, "Not in JPEG format !!"

        while (marker):
            first = getCharToOrd(self._file)
            if first != 0xff or first < 0:
                break
            marker = getCharToOrd(self._file)
            log("%s-%s"%(hex(first), hex(marker)))
            length = getBytes2(self._file)
            curPos = nowAt(self._file)
            log("length= %d, curPos=%d"%(length,curPos))

            if marker in [JPEG_EOI, JPEG_SOS]:
                log("EOI or SOS ... exit parsing")
                break
            elif marker == JPEG_APP0:
                log("Enter", "[APP0]", "add")
                log("Leave", "[APP0]", "remove")
                pass # TBD
            elif marker == JPEG_APP1:
                log("Enter", "[APP1]", "add")
                header = getChar(self._file, 4)
                log("header = %s"%(header))
                if header.lower() == 'exif':
                    self.__parseAPP1(curPos+6, curPos, curPos+length-2)
                elif header.lower() == 'http':
                    seekTo(self._file, curPos)
                    xmpBuffer = getChar(self._file, length)
                    checkURL = "http://ns.adobe.com/xap/1.0/"
                    if xmpBuffer.startswith(checkURL):
                        headLen = len(checkURL)
                        self.__parseXMP(xmpBuffer[headLen:], length-headLen)
                    pass
                log("Leave", "[APP1]", "remove")

            elif marker == JPEG_APP2:
                log("Enter", "[APP2]", "add")
                self.__parseAPP2(length)
                log("Leave", "[APP2]", "remove")
                pass # TBD
            elif marker == JPEG_APP13:
                log("Enter", "[APP13]", "add")
                log("Leave", "[APP13]", "remove")
                pass # TBD
            seekTo(self._file, curPos+length-2)
예제 #5
0
 def __parseAPP2(self, length):
     curPos = nowAt(self._file)
     iptcData = getChar(self._file, length)
     iccIdentifier = "ICC_PROFILE"
     if (iptcData.startswith(iccIdentifier)):
         iccData = iptcData[len(iccIdentifier) + 1:]
         iccLen = 0
         if ord(iccData[0]) == 0x01 and ord(iccData[1]) == 0x01:
             iccLen = length - 14
         elif ord(iccData[0]) == 0x01:  # multi-page, support header only
             iccLen = 128
         else:
             log("Wrong ICC Profile format !")
             return
         seekTo(self._file, curPos + 14)
         from ICCProfileParser import ICCProfileParser
         iccParser = ICCProfileParser(self._file)
         iccParser.parse()
     else:
         log("Wrong ICC Profile format !")
         assert False
 def __parseAPP2(self, length):
     curPos = nowAt(self._file)
     iptcData = getChar(self._file, length)
     iccIdentifier = "ICC_PROFILE"
     if (iptcData.startswith(iccIdentifier)):
         iccData = iptcData[len(iccIdentifier)+1:]
         iccLen = 0
         if ord(iccData[0]) == 0x01 and ord(iccData[1]) == 0x01:
             iccLen = length -14
         elif ord(iccData[0]) == 0x01: # multi-page, support header only
             iccLen = 128
         else:
             log("Wrong ICC Profile format !")
             return
         seekTo(self._file, curPos+14)
         from ICCProfileParser import ICCProfileParser
         iccParser = ICCProfileParser(self._file)
         iccParser.parse()
     else:
         log("Wrong ICC Profile format !")
         assert False
예제 #7
0
        def parseTagTable():
            log("Enter", "[ICCProfileTagTable]", "add")
            tagCount = getBytes4(self._fd)
            log("Tag count = %d"%(tagCount))
            for idx in xrange(tagCount):
                tagStartPos = nowAt(self._fd)
                sig = ''.join(getChar(self._fd) for _ in xrange(4))
                offset = getBytes4(self._fd)
                size = getBytes4(self._fd)
                seekTo(self._fd, basePos+offset)
                log("Tag sig(%s) / offset(%d) / size(%d) / basePos(%d) / tagSigPos(%d) / tagTypePos(%d) "%(sig, offset, size, basePos, tagStartPos, basePos+offset))
                typeDesc = ''.join(getChar(self._fd) for _ in xrange(4))
                log("Type Desc(%s)"%(typeDesc))
                sigDescObj = GetSigObject(sig, typeDesc, self._fd, size, basePos+offset)
                assert sig not in self.__dicSig2TagInfo, "Check this file, two same sig !"
                self.__dicSig2TagInfo[sig] = sigDescObj
                seekTo(self._fd, tagStartPos+12)

            log("Leave", "[ICCProfileTagTable]", "remove")
            pprint.pprint(self.__dicSig2TagInfo)
            pass
예제 #8
0
def GetMlucHelper(_fd, sig, tagStartPos):
    reserved = getBytes4(_fd)
    assert reserved == 0
    numOfRecords = getBytes4(_fd)
    recordSize = getBytes4(_fd)
    log(" numOfRecords = %d / recordSize = %s"%(numOfRecords, recordSize))

    sigDescObj = MultiLocalizedUnicode(sig)
    for _ in xrange(numOfRecords):
        langCode = ''.join(getChar(_fd) for i in xrange(2))
        langCountryCode = ''.join(getChar(_fd) for i in xrange(2))
        lenRecordString = getBytes4(_fd)
        offsetRecordString = getBytes4(_fd)

        here = nowAt(_fd)
        seekTo(_fd, tagStartPos + offsetRecordString)
        uniBytes = getChar(_fd, lenRecordString)
        # TODO : Think a better way to store these special unicode glyph
        uniChar = unicode(uniBytes, errors='replace')
        log(" uniChar = %s"%(uniChar))
        sigDescObj.add(langCode, langCountryCode, uniChar)
        seekTo(_fd, here)
    return sigDescObj
예제 #9
0
    def __parseBasicIFD(self, base, start, end):
        log("Enter", "[BasicIFD]", "add")

        if not self._file:
            assert False
        entries = getBytes2(self._file, self._orderAPP1)
        log("Number of entries = %d" % (entries))

        for idx in xrange(entries):
            tag = getBytes2(self._file, self._orderAPP1)
            dataFormat = getBytes2(self._file, self._orderAPP1)
            numOfComps = getBytes4(self._file, self._orderAPP1)
            posBeforeDataOffset = nowAt(self._file)
            dataOffset = getBytes4(self._file, self._orderAPP1)
            posAfterDataOffset = nowAt(self._file)

            if 0 == dataFormat or dataFormat >= len(EXIF_TIFF_DATAFORMAT_LIST):
                assert False, "dataformat incorrect = %d" % (dataFormat)
                continue
            bytesPerComp = EXIF_TIFF_DATAFORMAT_LIST[dataFormat]
            dataSize = bytesPerComp * numOfComps
            if dataSize > 4:
                targetOffset = base + dataOffset
                if targetOffset <= start or targetOffset >= end:
                    continue
                else:
                    seekTo(self._file, targetOffset)
            else:
                seekTo(self._file, posBeforeDataOffset)

            entry = self.__getDataFromFormat(tag, dataFormat, dataSize)
            if entry.getTag() == TAGID_ExifIFD:
                ifdOffset = entry.getValue()
                seekTo(self._file, base + ifdOffset)
                self.__parseIFDs(base, start, end, "ExifIFD")
            elif entry.getTag() == TAGID_SubIFDs:
                log("SubIFDs")
            elif entry.getTag() == TAGID_GPSIFD:
                ifdOffset = entry.getValue()
                seekTo(self._file, base + ifdOffset)
                self.__parseIFDs(base, start, end, IFD="GPSIFD")
                pass
            elif entry.getTag() == TAGID_IPTC:
                log("IPTC")
                pass
            elif entry.getTag() == TAGID_XMP:
                log("XMP")
                pass
            elif entry.getTag() == TAGID_Photoshop:
                log("Photoshop")
                pass
            elif entry.getTag() == TAGID_ICCProfile:
                log("ICCProfile")
                pass
            elif entry.getTag() == TAGID_DNGPrivateData:
                log("DNGPrivateData")
                pass

            seekTo(self._file, posAfterDataOffset)

        log("Leave", "[BasicIFD]", "remove")
    def __parseBasicIFD(self, base, start, end):
        log("Enter", "[BasicIFD]", "add")

        if not self._file:
            assert False
        entries = getBytes2(self._file, self._orderAPP1)
        log("Number of entries = %d"%(entries))

        for idx in xrange(entries):
            tag = getBytes2(self._file, self._orderAPP1)
            dataFormat = getBytes2(self._file, self._orderAPP1)
            numOfComps = getBytes4(self._file, self._orderAPP1)
            posBeforeDataOffset = nowAt(self._file)
            dataOffset = getBytes4(self._file, self._orderAPP1)
            posAfterDataOffset = nowAt(self._file)

            if 0 == dataFormat or dataFormat >= len(EXIF_TIFF_DATAFORMAT_LIST):
                assert False, "dataformat incorrect = %d"%(dataFormat)
                continue
            bytesPerComp = EXIF_TIFF_DATAFORMAT_LIST[dataFormat]
            dataSize = bytesPerComp * numOfComps
            if dataSize > 4:
                targetOffset = base + dataOffset
                if targetOffset <= start or targetOffset >= end:
                    continue
                else:
                    seekTo(self._file, targetOffset)
            else:
                seekTo(self._file, posBeforeDataOffset)

            entry = self.__getDataFromFormat(tag, dataFormat, dataSize)
            if entry.getTag() == TAGID_ExifIFD:
                ifdOffset = entry.getValue()
                seekTo(self._file, base+ifdOffset)
                self.__parseIFDs(base, start, end, "ExifIFD")
            elif entry.getTag() == TAGID_SubIFDs:
                log("SubIFDs")
            elif entry.getTag() == TAGID_GPSIFD:
                ifdOffset = entry.getValue()
                seekTo(self._file, base+ifdOffset)
                self.__parseIFDs(base, start, end, IFD="GPSIFD")
                pass
            elif entry.getTag() == TAGID_IPTC:
                log("IPTC")
                pass
            elif entry.getTag() == TAGID_XMP:
                log("XMP")
                pass
            elif entry.getTag() == TAGID_Photoshop:
                log("Photoshop")
                pass
            elif entry.getTag() == TAGID_ICCProfile:
                log("ICCProfile")
                pass
            elif entry.getTag() == TAGID_DNGPrivateData:
                log("DNGPrivateData")
                pass


            seekTo(self._file, posAfterDataOffset)

        log("Leave", "[BasicIFD]", "remove")
예제 #11
0
    def __parseICCProfile(self):
        # Refer to http://blog.fpmurphy.com/2012/03/extract-icc-profile-from-images.html

        basePos = nowAt(self._fd)
        def parseHeader():
            log("Enter", "[ICCProfileHeader]", "add")
            profileSize = getBytes4(self._fd)

            cmmType = ''.join(getChar(self._fd) for _ in xrange(4))
            lstVer = [str(getCharToOrd(self._fd)) for _ in xrange(4)]
            self.__dicHeaderInfo[H_CMM_TYPE] = cmmType
            self.__dicHeaderInfo[H_VERSION] = lstVer[0] + "." + lstVer[1]

            deviceClass = ''.join(getChar(self._fd) for _ in xrange(4))
            colorSpaceOfData = ''.join(getChar(self._fd) for _ in xrange(4))
            pcs = ''.join(getChar(self._fd) for _ in xrange(4))
            self.__dicHeaderInfo[H_DEVICE_CLASS] = dicDevCls2Name.get(deviceClass, "Not found")
            self.__dicHeaderInfo[H_COLOR_SPACE] = colorSpaceOfData.strip()
            self.__dicHeaderInfo[H_PROFILE_CONNECTION_SPACE] = pcs.strip()

            lstDatetime = [getBytes2(self._fd) for _ in xrange(6)]
            signature = ''.join(getChar(self._fd) for _ in xrange(4))
            assert signature == "acsp", "Not a standard ICC Profile !!"
            primaryPlatform = ''.join(getChar(self._fd) for _ in xrange(4))

            def getBitsList(numBytes):
                lstBits = []
                for _ in xrange(numBytes):
                    bits_short = bin(getCharToOrd(self._fd))[2:]
                    bits_full = '00000000'[len(bits_short):] + bits_short
                    lstBits.extend([int(b) for b in bits_full])
                return lstBits

            lstProfileFlags = getBitsList(4)
            self.__dicHeaderInfo[H_CREATE_DATETIME] = "Datatime = %d/%d/%d-%d:%d:%d"%tuple(lstDatetime)
            self.__dicHeaderInfo[H_SIGNATURE] = signature
            self.__dicHeaderInfo[H_PLATFORM] = dicPlatformSig2Desc.get(primaryPlatform, "Not found")
            self.__dicHeaderInfo[H_IS_EMBEDED] = True if lstProfileFlags[0] == 1 else False
            self.__dicHeaderInfo[H_USED_INDENDENTLY] = False if lstProfileFlags[1] == 1 else True

            deviceManufacturer = ''.join(getChar(self._fd) for _ in xrange(4))
            deviceModel = ''.join(getChar(self._fd) for _ in xrange(4))
            lstDeviceAttributes = getBitsList(8)
            renderingIntent, zeroPadding = getBytes2(self._fd), getBytes2(self._fd)

            self.__dicHeaderInfo[H_DEVICE_MANUFACTURER] = deviceManufacturer
            self.__dicHeaderInfo[H_DEVICE_MODEL] = deviceModel
            self.__dicHeaderInfo[H_ATTR_T_R] = "Transparency" if lstDeviceAttributes[0] == 1 else "Reflective"
            self.__dicHeaderInfo[H_ATTR_M_G] = "Matte" if lstDeviceAttributes[1] == 1 else "Glossy"
            self.__dicHeaderInfo[H_RENDERING_INTENT] = dicRenderingIntent2Desc.get(renderingIntent, "Not found")

            intX, intY, intZ = getBytes4(self._fd), getBytes4(self._fd), getBytes4(self._fd)
            X = struct.unpack('f', struct.pack('i', intX))
            Y = struct.unpack('f', struct.pack('i', intY))
            Z = struct.unpack('f', struct.pack('i', intZ))
            CIEXYZ_X = X[0] / Y[0]
            CIEXYZ_Y = Y[0] / Y[0]
            CIEXYZ_Z = Z[0] / Y[0]

            profileCreator = ''.join(getChar(self._fd) for _ in xrange(4))
            profileID = [hex(getCharToOrd(self._fd)) for _ in xrange(16)]
            reserved = [hex(getCharToOrd(self._fd)) for _ in xrange(28)]

            self.__dicHeaderInfo[H_PROFILE_CREATOR] = profileCreator
            self.__dicHeaderInfo[H_PROFILE_D50_XYZ] = "(%f, %f, %f)"%(CIEXYZ_X, CIEXYZ_Y, CIEXYZ_Z)
            log("Header Information : \n%s "%(pprint.pformat(self.__dicHeaderInfo, indent=2)))
            log("Leave", "[ICCProfileHeader]", "remove")

        def parseTagTable():
            log("Enter", "[ICCProfileTagTable]", "add")
            tagCount = getBytes4(self._fd)
            log("Tag count = %d"%(tagCount))
            for idx in xrange(tagCount):
                tagStartPos = nowAt(self._fd)
                sig = ''.join(getChar(self._fd) for _ in xrange(4))
                offset = getBytes4(self._fd)
                size = getBytes4(self._fd)
                seekTo(self._fd, basePos+offset)
                log("Tag sig(%s) / offset(%d) / size(%d) / basePos(%d) / tagSigPos(%d) / tagTypePos(%d) "%(sig, offset, size, basePos, tagStartPos, basePos+offset))
                typeDesc = ''.join(getChar(self._fd) for _ in xrange(4))
                log("Type Desc(%s)"%(typeDesc))
                sigDescObj = GetSigObject(sig, typeDesc, self._fd, size, basePos+offset)
                assert sig not in self.__dicSig2TagInfo, "Check this file, two same sig !"
                self.__dicSig2TagInfo[sig] = sigDescObj
                seekTo(self._fd, tagStartPos+12)

            log("Leave", "[ICCProfileTagTable]", "remove")
            pprint.pprint(self.__dicSig2TagInfo)
            pass

        parseHeader()
        parseTagTable()
예제 #12
0
def GetAToBHelper(_fd, sig, tagStartPos, reverse=False):
    reserved = getBytes4(_fd)
    assert reserved == 0
    numOfInputChannel = getCharToOrd(_fd)
    numOfOutputChannel = getCharToOrd(_fd)
    padding = getBytes2(_fd)
    log(" Input(%d) , Output(%d), padding(%d)"%(numOfInputChannel, numOfOutputChannel, padding))
    assert padding == 0

    sigDescObj = None
    lstBCurve = []
    mMat = None
    lstMCurve = []
    clut = []
    lstACurve = []

    offset2BCurve = getBytes4(_fd)
    if offset2BCurve != 0:
        here = nowAt(_fd)
        seekTo(_fd, tagStartPos + offset2BCurve)
        for _ in xrange(numOfOutputChannel):
            subType = getChar(_fd, 4)
            log(" B Curve subtype = %s"%(subType))
            if subType == "para":
                sigSubDescObj = GetParaCurveHelper(_fd, sig)
                lstBCurve.append(sigSubDescObj)
            elif subType == "curv":
                sigSubDescObj = GetCurveHelper(_fd, sig)
                lstBCurve.append(sigSubDescObj)
        seekTo(_fd, here)
        assert len(lstBCurve) == numOfOutputChannel

    offset2Matrix = getBytes4(_fd)
    if offset2Matrix != 0:
        here = nowAt(_fd)
        seekTo(_fd, tagStartPos + offset2Matrix)
        mat = []
        for _ in xrange(12):
            intUnsigned = getBytes2(_fd)
            intSigned = intUnsigned - 65536 if intUnsigned >= 32768 else intUnsigned
            fracPart = getBytes2(_fd)
            v = intSigned + float(fracPart) / 65536
            mat.append(v)
        log(" Matrix = %s"%(str(mat)))
        mMat = S15Fixed16Array(sig, mat)
        seekTo(_fd, here)

    offset2MCurve = getBytes4(_fd)
    if offset2MCurve != 0:
        here = nowAt(_fd)
        seekTo(_fd, tagStartPos + offset2MCurve)
        for _ in xrange(numOfOutputChannel):
            subType = getChar(_fd, 4)
            log(" M Curve subtype = %s"%(subType))
            if subType == "para":
                sigSubDescObj = GetParaCurveHelper(_fd, sig)
                lstMCurve.append(sigSubDescObj)
            elif subType == "curv":
                sigSubDescObj = GetCurveHelper(_fd, sig)
                lstMCurve.append(sigSubDescObj)
        seekTo(_fd, here)
        assert len(lstMCurve) == numOfOutputChannel

    offset2CLUT = getBytes4(_fd)
    if offset2CLUT != 0:
        # TODO : Check the implementation correctness
        here = nowAt(_fd)
        seekTo(_fd, tagStartPos + offset2CLUT)

        lstGridPoints = []
        for _ in xrange(16):
            gridPts = getCharToOrd(_fd)
            if _ >= numOfInputChannel:
                assert gridPts == 0
            lstGridPoints.append(gridPts)
        precision = getCharToOrd(_fd)
        padding = getBytes3(_fd)
        log(" >>> lstGridPoints : %s"%(str(lstGridPoints)))
        log(" >>> precision : %s / padding %s "%(str(precision), str(padding)))
        assert padding == 0
        getDataPoint = getBytes2 if precision == 2 else getCharToOrd

        def fn(x, y):
            return x * y if y != 0 else x
        totalCLUTPts = reduce(fn, lstGridPoints)
        for _ in xrange(totalCLUTPts):
            tmp = []
            for __ in xrange(numOfOutputChannel):
                tmp.append(getDataPoint(_fd))
            clut.append(tmp)
        seekTo(_fd, here)

    offset2ACurve = getBytes4(_fd)
    if offset2ACurve != 0:
        here = nowAt(_fd)
        seekTo(_fd, tagStartPos + offset2ACurve)
        for _ in xrange(numOfOutputChannel):
            subType = getChar(_fd, 4)
            log(" A Curve subtype = %s"%(subType))
            if subType == "para":
                sigSubDescObj = GetParaCurveHelper(_fd, sig)
                lstACurve.append(sigSubDescObj)
            elif subType == "curv":
                sigSubDescObj = GetCurveHelper(_fd, sig)
                lstACurve.append(sigSubDescObj)
        seekTo(_fd, here)
        assert len(lstACurve) == numOfOutputChannel

    log(" O2B(%d) / O2mat(%d) / O2M(%d) / O2CLUT(%d) / O2A(%d)"%(offset2BCurve,\
        offset2Matrix, offset2MCurve, offset2CLUT, offset2ACurve))

    if reverse:
        sigDescObj = LutBToA(sig, lstBCurve, mMat, lstMCurve, clut, lstACurve)
    else:
        sigDescObj = LutAToB(sig, lstBCurve, mMat, lstMCurve, clut, lstACurve)
    return sigDescObj