Changing them requires changing of *ALL* the numbers. 24.118.95.84 (sig added by Cburnett) You're point is irrelevant as everything is based on the matrix here. Cburnett 02:11, (UTC) I contacted the original author of the example to determine which of the numbers to correct. I re-ran all the numbers and just pasted them in. Which of the two numbers was wrong? - 24.118.95.84 (sig added by Cburnett) You'll have to go into the history and check. How's that now? Cburnett 03:58, (UTC) Not sure.
Hopefully the author of this page can clear up the inconsistency. These matrices, with same inconsistency, also appear in the second edition of the Gonzalez/Woods book Digital Image Processing, second editon, page 499. It is not clear which of the two matrices is wrong, except that the discrete cosine transform result matches the second matrix rather than the first. In the example 8 by 8 matrix to be put through the jpeg compression algorithm, there is something wrong with the entry 68 in row 6, column 6, because subtracting 128 does not give the asserted result -65 in the next displayed matrix. This formalization of the contents of the JFIF header within the previously defined APP0 block is the only 'entension'. That JFIF header is written in a block with an APP0 marker, which is part of the JPEG standard but whose contents are not defined in the JPEG standard (they are application specific). It's also an extension of the JPEG Interchange Format in that they created a standardized JFIF header, which was necessary so that decoders could reliably identify a file meeting the JFIF standard. So, what is it? Stolsvik ( talk) 14:27, 11 January 2008 (UTC) It's a bit of both! It's a concatenation of the JPEG Interchange Format in that it uses a subset of the elements in the JPEG standard.
This is often confused with the JPEG File Interchange Format (JFIF), a minimal version of the JPEG Interchange Format that was deliberately simplified so that it could be widely implemented and thus become the de-facto standard.", while the JFIF page states that JFIF is an extension of JPEG Interchange Format. The JPEG page states "The file format is known as 'JPEG Interchange Format', as specified in Annex B of the standard.
0 kommentar(er)
