AS は「test="おはよう"」「test2="こんばんは"」という二行を埋め込み、テキストフィールドに表示するようにしています。

　差し替え前の jpeg
　

　差し替え後の jpeg
　

　データ差し替え前の swf
　

　データ差し替え後の swf
　

差し替え後の swf を見ると、jpeg 画像が全て表示しきれていません。jpeg の表示領域設定が、差し替え前の jpeg のもののままになっているからです。

差し替えた jpeg の表示領域を変更したい場合、DefineBitsJPEG タグの後に登場する DefineShape タグのデータを変更する必要あります。jpeg 表示領域変更処理は今後必要時に作成する予定です。

　・参考
　Elementary Note : FLASH解析(JPEG差し替え編)
　http://reindrop.wordpress.com/2008/08/28/flash解析jpeg差し替え編/

以下は今回作成した JPEG バイナリ解析処理用クラスです。ご参考程度にどうぞ。

from struct import *

class JpegChunkSet:
	
	def __init__(self):
		
		self.__SWF_VERSION_THAT_USES_ERRONEOUS_HEADER = 7
		
		self.__BINARY_OF_SOI = "\xff" + "\xd8"
		self.__BINARY_OF_EOI = "\xff" + "\xd9"
		
		self.__jpegChunkSet = []
		
	def parse(self, binarySet):
		
		markerType = MarkerType()
		encodingTablesBinarySet = ""
		imageDataBinarySet = ""
		
		binaryLength = len(binarySet)
		index = 0
		while index < binaryLength:
			
			jpegChunk = JpegChunk()
			index = jpegChunk.create(binarySet, index, markerType, binaryLength)
			self.__jpegChunkSet.append(jpegChunk)
			
			if markerType.isEncodingTables(jpegChunk.getType()):
				encodingTablesBinarySet = encodingTablesBinarySet + jpegChunk.pack()
			
			else:
				imageDataBinarySet = imageDataBinarySet + jpegChunk.pack()
			
		encodingTablesBinarySet = self.__BINARY_OF_SOI + encodingTablesBinarySet + self.__BINARY_OF_EOI
		
		self.__contentForDefineBitsJPEG2 = encodingTablesBinarySet + imageDataBinarySet
	
	def checkWhetherToUseErroneousHeader(self, swfVersion):
		return swfVersion <= self.__SWF_VERSION_THAT_USES_ERRONEOUS_HEADER
	
	def getErroneousHeader(self):
		return self.__BINARY_OF_EOI + self.__BINARY_OF_SOI
	
	def getContentForDefineBitsJPEG2(self):
		return self.__contentForDefineBitsJPEG2
		
	def toString(self):
		
		print "--- jpeg ---"
		for jpegChunk in self.__jpegChunkSet:
			jpegChunk.toString()


class JpegChunk:
	
	def __init__(self):
		
		self.__MARKER_FIELD_BYTE = 2
		self.__LENGTH_FIELD_BYTE = 2
		
		self.__lengthFieldBinary = ""
		self.__appDataBinary = ""
	
	def create(self, binarySet, index, markerType, binaryLength):
		
		n = index + self.__MARKER_FIELD_BYTE
		markerFieldBinary = binarySet[index:n]
		
		if ord(markerFieldBinary[0]) != 0xff:
			raise Exception("error", ord(markerFieldBinary[0]))
		
		self.__markerFieldBinary = markerFieldBinary
		self.__type = ord(markerFieldBinary[1])
		
		index = n
			
		if markerType.isSOI(self.__type) or markerType.isEOI(self.__type):
			return index
			
		elif markerType.isSOS(self.__type) or markerType.isRST(self.__type):
			
			n = index
			while n < binaryLength:
				
				if ord(binarySet[n]) == 0xff and ord(binarySet[n + 1]) != 0x00:
					break
				
				else:
					n = n + 1
			
			if n >= binaryLength:
				raise Exception("error2")
			
			self.__appDataBinary = binarySet[index:n]
			
			return n
		
		else:
			n = index + self.__LENGTH_FIELD_BYTE
			self.__lengthFieldBinary = binarySet[index:n]
			length = unpack(">H", self.__lengthFieldBinary)[0]
			
			index = n
			n = index + length - self.__LENGTH_FIELD_BYTE
			self.__appDataBinary = binarySet[index:n]
			
			return n

	def pack(self):
		
		return self.__markerFieldBinary + self.__lengthFieldBinary + self.__appDataBinary
	
	def getType(self):
		return self.__type

	def toString(self):
		
		print "0x%x" % self.__type
		
		if self.__lengthFieldBinary != "":
			print " length", unpack(">H", self.__lengthFieldBinary)[0]
		
		if self.__appDataBinary != "":
			print " appDataLength", len(self.__appDataBinary)
		
		print " chunk length", len(self.pack())
		
		
class MarkerType:
	
	def isSOI(self, type):
		return type == 0xd8
	
	def isEOI(self, type):
		return type == 0xd9
	
	def isSOS(self, type):
		return type == 0xda
	
	def isRST(self, type):
		
		i = 0xd0
		while i <= 0xd7:
			if type == i:
				return True
			i = i + 1
			
		return False
	
	def isDQT(self, type):
		return type == 0xdb
	
	def isDHT(self, type):
		return type == 0xc4
	
	def isEncodingTables(self, type):
		return self.isDQT(type) or self.isDHT(type)