Hi, there are two things I don’t understand. I use these settings (click to view full size): http://250kb.de/u/061203/p/t/6aa02a4e.png (Block split threshold is set to {64,80,96,128,160,192,224,256,320,384,448,512,768,1024,2048,0}.)
When I have an image with more than 256 colours, it uses RGB mode, as they won't fit into the palette. When I set bit depth to auto, I get 102 jobs, with "all", I get 408. Since the bit depth doesn't matter for RGB (am I right?) – does PNGOutWin every calculation 4 times with the same input and output (except different randomized Huffman tables)? The tooltip shows bit depth 1, 2, 4 and 8 for waiting jobs and 8 for every finished job.
Sometimes I see "Pass 0" and in some cases even "Pass -1" – is that something special? I see pass 0 when converting, for example, this image: http://8bitpeoples.com/_images/discog/printable/nullsleep_-_wooden_papers_PRINT.gif with the settings shown above.
Furthermore, I'd like to suggest two things:
The possibility to press the "Clear job list" button while mode is "running". I'm not sure if it should also cancel the running job.
A possibility to disable the confirmation dialogue for clearing the job list.
Edited by Martin at
Martin at
Re: PNGOutWin passes
I think a line like this: Images: 7 | Passes per image: 3 | Resulting jobs: 21 in the multiple trials dialogue would be very useful, to help choosing a good tradeoff between time and potential compression advantages.
Awesoken at
When I have an image with more than 256 colours ... set bit depth to ... "all" ...
Ah, I can fix that. The PNGOUT library should generate an error message if a bitdepth of /d1, /d2, or /d4 is selected in conjunction with color type /c2 (RGB) or /c6 (RGBA). The current version is simply overwriting the bitdepth to 8 in those color modes. This will be fixed in the next release.
Sometimes I see "Pass 0" and in some cases even "Pass -1"
I do a first pass to generate filtered data for the block split finder.
I'll let David handle the GUI issues.
David at
Martin said at
[...] When I have an image with more than 256 colours, it uses RGB mode, as they won't fit into the palette. When I set bit depth to auto, I get 102 jobs, with "all", I get 408. [...]
Furthermore, I'd like to suggest two things:
The possibility to press the "Clear job list" button while mode is "running". I'm not sure if it should also cancel the running job.
A possibility to disable the confirmation dialogue for clearing the job list.
Thank you for this great suggestion on pruning trials. I emailed you a build to try out.
I will add the GUI suggestions to the list for the next release.
Martin at
The build you sent me works as expected, thanks :)
Martin at
Selecting all 3 checkboxes for different palette orders also triples the number of jobs of RGB images.
David at
Martin said at
Selecting all 3 check boxes for different palette orders also triples the number of jobs of RGB images.
With color mode RGB, only one trial is created.
I think what you mean is with an RGB image and color mode Auto, you get one trial per palette order option.
The only way to address this is to add pre-processing of images.
Martin at
David said at
I think what you mean is with an RGB image and color mode Auto, you get one trial per palette order option.
Yes, that's what I meant to say.
David said at
The only way to address this is to add pre-processing of images.
That would be the best way. An alternative way is to choose one of the palette order modes and skip the others, similar to the bitdepth handling in the build you sent me.
counting_pine at
Of the three palette options (preserve; optimize; regenerate), Optimize is probably the least "contradictory" to the idea of RGB compression, and I think it's also the default on the dialog. So that would be the logical choice if you had to go for one of them. Another alternative would be a hidden, implicit "this is not a palette image" checkbox, but that would create extra trials that would always fail on a palette image, so I wouldn't recommend that one. I like the image pre-processing idea best. It could also allow more intelligent pruning in other areas as well. I recognise that it's probably much more difficult to implement than the other possibilities though.