I am trying to get the Python 2.7 PIL Library to work with JPEG images that are only available as a stream coming from a HDD image and are not complete. I have set the option: ImageFile.LOAD_TRUNCATED_IMAGES = True And load the stream as far as it is available (or better said: as far as I am 100% sure that this data is still a image, not some other file type). I have tested different things and as far as I can tell (for JPEGs) PIL only accepts it as a valid JPEG Image if it finds the 0xFFDA (Start of Scan Marker). This is a short example of how I load the data: from PIL import Image from StringIO import StringIO ImageFile.LOAD_TRUNCATED_IMAGES = True with open("/path/to/image.raw", 'rb') as fp: fp.seek("""jump to position in image where JPEG starts""") data = fp.read("""number of bytes I know that those belong to that jpeg""") img = Image.open(StringIO(data)) # This would throw exception if the data does # not contain the 0xffda marker pixel = img.load() # Would throw exception if LOAD_TRUNCATED_IMAGES = false height,width = img.size for i in range(height): for j in range(width): print pixel[i,j] On the very last line I expected (or hoped) to see at least the read pixel data to be displayed. But for every pixel it returns (0,0,0). The Question: Is what I am trying here not possible with PIL? Some weeks ago I tried the same with a image file I truncated myself, simply by cutting data from it with an editor. It worked for the pixel-data that was available. As soon as it reached a pixel that I cut off, the program threw an exception (I will try this again later today to make sure that I am not remembering wrong). If somebody is wondering why I am doing this: I need to make sure that the image/picture inside that hdd image is in consecutive blocks/clusters and is not fragmented. To make sure of this I wanted to use pixel matching. EDIT: I have tried it again and this is what I have seen. I opened a truncated image in GIMP and it showed me a few pixel lines in the upper part, but PIL was not able to at least give me the RGB values of those pixels. It always returns (0,0,0). I made the image slightly bigger such that the lower 4/5 of the image was not visible, but that was enough for PIL to show me the RGB values that were available. Everything else was (0,0,0). I am still not 100% sure whether PIL can show me the RGB values, even if only view pixel-data is available. Continue reading...
