"export" vs. "save as / writing options"
Posted: Wed Aug 23, 2006 5:51 pm
Hi
This new version sounds great. Congratulations!
Thanks to have added a chroma subsampling option for JPEG files (in the export command)
By the way, I am wondering why there are two separate but somewhat similar ways to save a file in a given format with some control parameters: "save as / options" and "export", with more or less the same parameters, although the "export" command in general allows a little bit more controls than the "save as / option" command.
Why not to merge these two commands in a single "save as" command with all the controls grouped in the "writing options" ?
I also performed some tests in saving a BMP file in JPEG through the export command. The work is done properly in any case (no bug), but the following point sounds strange:
export with 16m color mode, Quality=95, DCT=slow, smoothing=0, subsampling=2x2,1x1,1x1, non-progressive and no huffman optimization gives exactly the same result (same file size and same content) as "save as" where options are non-progressive, no huffman optimization, and quality=95
But if "optimize huffman table" is marked in both commands (all other parameters being as mentioned above), the results are different in terms of file size (although the pixel content remain identical: checked in using an aritmetic difference function which leads to fully black picture - color count=1)
initial BMP: 4651 ko
JPEG "export" or "save as" without huffman optimization: 436 ko (as save as of 1.82 version)
JPEG "save as" with huffman optimization: 424 ko (as save as of 1.82 version)
but JPEG "export" with huffman optimization: 409 ko only !!!
XnView 1.90 <x>
This new version sounds great. Congratulations!
Thanks to have added a chroma subsampling option for JPEG files (in the export command)
By the way, I am wondering why there are two separate but somewhat similar ways to save a file in a given format with some control parameters: "save as / options" and "export", with more or less the same parameters, although the "export" command in general allows a little bit more controls than the "save as / option" command.
Why not to merge these two commands in a single "save as" command with all the controls grouped in the "writing options" ?
I also performed some tests in saving a BMP file in JPEG through the export command. The work is done properly in any case (no bug), but the following point sounds strange:
export with 16m color mode, Quality=95, DCT=slow, smoothing=0, subsampling=2x2,1x1,1x1, non-progressive and no huffman optimization gives exactly the same result (same file size and same content) as "save as" where options are non-progressive, no huffman optimization, and quality=95
But if "optimize huffman table" is marked in both commands (all other parameters being as mentioned above), the results are different in terms of file size (although the pixel content remain identical: checked in using an aritmetic difference function which leads to fully black picture - color count=1)
initial BMP: 4651 ko
JPEG "export" or "save as" without huffman optimization: 436 ko (as save as of 1.82 version)
JPEG "save as" with huffman optimization: 424 ko (as save as of 1.82 version)
but JPEG "export" with huffman optimization: 409 ko only !!!
XnView 1.90 <x>