OverflowNow back in the corrupt file, I searched for FFD9FFDB and found it at 0x10010. As far as I can tell, everything is where it should be.
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I then started to increase the length in the corrupted file randomly and see what error messages convert would give me, but that's more like being in a completely dark room with a metal bucket and throwing rocks until I hear that I've hit the bucket.īut let's see what is at the end of the APP1 segment in the valid file:Ġ圎042: FD CF FF D9 FF DB 00 84At 0圎044, which is 0圎042 plus the SOI marker before the APP1 segment, it says FFD9 and the EXIF specification tells us that this is the EOI ( End Of Image) marker followed by FFDB, which is the DQT ( Define Quantization Table) marker, see Table 40 of the specification. The length of the APP1 segment in the corrupt file is only 0圎 = 14? That should be far too small.
So, is the SOI marker here wrong?Ī valid JPEG fileSince I don't have the slightest idea of what exactly is wrong here, I opened another JPEG that works and was taken only minutes before the corrupt one. It also said that it had 1072 extraneous bytes before marker 0xd8, which is only slightly smaller than the area between the APP1 header and the next SOI marker. So I searched for another occurence of FFD8 and found one at 0x442 = 1090. Okay, so FFD8 is a SOI marker and the error message says that the file has two of them, which apparently is a bad thing. Using the EXIF specification (PDF), we learn that marks the start of an application segment 1 ( APP1). What you see here, is a JPEG file ( FF D8) followed by some EXIF information ( FF E1). The EXIF standardThe only helpful googling those error messages brought up was to use a hex editor. That's obviously not sufficient to get to the bottom of this, so I used GIMP and ImageMagicks convert, which both gave me the same information:Ĭonvert: Corrupt JPEG data: 1072 extraneous bytes before marker 0xd8 `test.jpg' warning/jpeg.c/EmitMessage/231.Ĭonvert: Invalid JPEG file structure: two SOI markers `test.jpg' error/jpeg.c/EmitMessage/236.Ĭonvert: missing an image filename `out.jpg' error/convert.c/ConvertImageCommand/3011.So, the two valuable information were:ġ072 extraneous bytes before marker 0xd8and The ProblemStandard (linux) picture viewer applications would just say that they can't open the file. Tl dr: The Samsung Galaxy S2 can occasionally create corrupted JPEGs, i.e., files that don't follow the specifications. I think I've already spent more than two hours searching the not-so-all-knowing internet for solutions, but in the end it came down to using my brain and reading the EXIF specification (PDF). Being a nerd, I couldn't resist and had to investigate the issue. While organizing some of the pictures I took with my Samsung Galaxy S2, I've encountered one file that couldn't be opened.
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