Re: EXIF support in PNG

hopefully someone can help me with checking if I read the JEITA spec 
correctly

below a piece of a jpeg image, apparently captured with a Nexus 4 phone

ffd8		Start of Image
ffe1		APP1 Marker
72b5		length of APP1
4578 6966	Exif (ASCII)
0000
4D4D		MM - big endian
002a

if this would be little endian (II instead of MM) then the length field 
would have been "b5 72" ?

then on row 000072a0 -- because the APP1 length is 72b5, then we need to 
add one byte for the SOI, therefore I think the last bytes of the EXIF 
APP1 are "ca b7 ad 24"

am I doing this correct ?

Willem


00000000  ff d8 ff e1 72 b5 45 78  69 66 00 00 4d 4d 00 2a 
|....r.Exif..MM.*|
00000010  00 00 00 08 00 08 01 0f  00 02 00 00 00 04 4c 47 
|..............LG|
00000020  45 00 01 10 00 02 00 00  00 08 00 00 00 6e 01 1a 
|E............n..|
00000030  00 05 00 00 00 01 00 00  00 76 01 1b 00 05 00 00 
|.........v......|
00000040  00 01 00 00 00 7e 01 28  00 03 00 00 00 01 00 02 
|.....~.(........|
00000050  00 00 02 13 00 03 00 00  00 01 00 01 00 00 87 69 
|...............i|
00000060  00 04 00 00 00 01 00 00  00 86 88 25 00 04 00 00 
|...........%....|
00000070  00 01 00 00 01 72 00 00  02 4c 4e 65 78 75 73 20 
|.....r...LNexus |
00000080  34 00 00 00 00 48 00 00  00 01 00 00 00 48 00 00 
|4....H.......H..|
00000090  00 01 00 0c 82 9a 00 05  00 00 00 01 00 00 01 1c 
|................|
000000a0  88 27 00 03 00 00 00 01  00 64 00 00 90 00 00 07 
|.'.......d......|
000000b0  00 00 00 04 30 32 32 30  90 03 00 02 00 00 00 14 
|....0220........|
000000c0  00 00 01 24 90 04 00 02  00 00 00 14 00 00 01 38 
|...$...........8|
000000d0  91 01 00 07 00 00 00 04  01 02 03 00 92 0a 00 05 
|................|
000000e0  00 00 00 01 00 00 01 4c  a0 00 00 07 00 00 00 04 
|.......L........|
000000f0  30 31 30 30 a0 01 00 03  00 00 00 01 00 01 00 00 
|0100............|
00000100  a0 02 00 04 00 00 00 01  00 00 0c c0 a0 03 00 04 
|................|
00000110  00 00 00 01 00 00 09 90  a0 05 00 04 00 00 00 01 
|................|
00000120  00 00 01 54 00 00 00 00  00 00 00 01 00 00 02 03 
|...T............|
00000130  32 30 31 33 3a 30 35 3a  32 32 20 31 36 3a 33 31  |2013:05:22 
16:31|
00000140  3a 31 33 00 32 30 30 32  3a 31 32 3a 30 38 20 31 
|:13.2002:12:08 1|
00000150  32 3a 30 30 3a 30 30 00  00 00 01 cc 00 00 00 64 
|2:00:00........d|
********
000072a0  a8 3f ca b7 ad 24 69 ad  a3 69 06 d9 31 87 50 7a 
|.?...$i..i..1.Pz|
000072b0  37 71 f9 d4 cb 71 a3 ff  d9 ff db 00 84 00 02 01 
|7q...q..........|
********



-- 
Willem van Schaik
[email protected]

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