Re: [Gimp-developer] New option Use custom quality settings for JPEG files
Hi Raphael, On Sun, 2007-08-12 at 23:44 +0200, Raphaël Quinet wrote: Since Friday, I added a new option to the JPEG save dialog: Use custom quality settings. If some quantization tables were attached to the image when it was loaded, then this option allows you to use them instead of the standard ones (different quantization tables are generated by the IJG JPEG library for each quality level). Why do we need an option in the GUI for this? If there are quantization tables attached and the user doesn't change the save quality, then just use them. Or is there a real disadvantage in doing that? To me it looks like you are asking the user a question that she is unlikely going to understand. And you are forcing the user to make a decision that you can better do for her. Sven ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
Re: [Gimp-developer] New option Use custom quality settings for JPEG files
On Mon, 13 Aug 2007 09:22:58 +0200, Sven Neumann [EMAIL PROTECTED] wrote: On Sun, 2007-08-12 at 23:44 +0200, Raphaël Quinet wrote: Since Friday, I added a new option to the JPEG save dialog: Use custom quality settings. If some quantization tables were attached to the image when it was loaded, then this option allows you to use them instead of the standard ones (different quantization tables are generated by the IJG JPEG library for each quality level). Why do we need an option in the GUI for this? If there are quantization tables attached and the user doesn't change the save quality, then just use them. Or is there a real disadvantage in doing that? To me it looks like you are asking the user a question that she is unlikely going to understand. And you are forcing the user to make a decision that you can better do for her. I think that this option is still useful. Maybe not for disabling it when it is enabled, but for enabling it when it is not enabled automatically. It is usually better to use the custom quantization tables if they are better than your default quality settings. But if they are not better, then it is nice to give a choice to the user. If the quantization tables found in the original file are not better than your default quality settings, then the option Use custom quality settings will be available but not enabled. This ensures that you always get at least the minimum quality specified in your defaults. If you did not make major changes to the image and you want to save it using the same quality as the original, then you can do it by enabling this option. -Raphaël ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
Re: [Gimp-developer] New option Use custom quality settings for JPEG files
Why don't add such a wonderful floating tip with a short description of the switch and not to revoke the possibility from a user? Raphaël Quinet wrote: I think that this option is still useful. Maybe not for disabling it when it is enabled, but for enabling it when it is not enabled automatically. It is usually better to use the custom quantization tables if they are better than your default quality settings. But if they are not better, then it is nice to give a choice to the user. -- With respect Alexander Rabtchevich ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
Re: [Gimp-developer] New option Use custom quality settings for JPEG files
On Mon, 13 Aug 2007 11:16:15 +0300, Alexander Rabtchevich [EMAIL PROTECTED] wrote: Why don't add such a wonderful floating tip with a short description of the switch and not to revoke the possibility from a user? This is already done. There is a tooltip associated with that option and it explains what it can be used for. Just try it an see for yourself... Sven is right to be concerned about the number of options in the JPEG save dialog. But as I explained in my previous message, this one is useful so that is why I added it. Besides the option Force baseline JPEG that I removed last Friday, there are other options that could be removed in the future: - the choice of DCT method (integer, fast but less accurate integer, or floating-point) because the speed differences are not significant anymore, - the ability to add restart markers because unreliable channels are much less common nowadays, - the smoothing option because this can also be performed by the usual blur filters. All these options could still be available through the PDB interface for those who really miss them, but otherwise I think that they should be removed from the advanced options soon after GIMP 2.4 is released. It will then be time to think about redesigning the JPEG save dialog from scratch. As I mentioned earlier, I would like to simplify that dialog and only have a dozen presets for the quality settings instead of having the 101 values in the quality slider plus the choice of chroma subsampling in the advanced options. Picking one of these presets would select the corresponding quality level (quantization tables) and the most appropriate chroma subsampling. These may still be available in the advanced options, but most users would never have to worry about them. I am not sure if the best way to make a choice among the dozen presets would be a set of radio buttons, a slider with discrete values or a combo box, but this is something that we can discuss later when we redesign that window. -Raphaël ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
Re: [Gimp-developer] New option Use custom quality settings for JPEG files
Raphaël, I would object to removal of DCT method settings switch. Make a simple but clear test case - open any file from RAW and save it with 100% quality, 1x1,1x1,1x1 subsampling and integer vs float DCT method. Then open two resulted files as 2 layers, subtract, flatten and look at the histogram. If set upper slider to 10 and medium to 5, you will see rather significant difference between two files. The reason is to make user possible to obtain as much quality jpg as possible if he wishes so. Note, that the majority of photo labs only accepts jpgs. Also if one prefer storing his images in loss format, but as qualitatively as possibly why prevent him from doing so? Raphaël Quinet wrote: Sven is right to be concerned about the number of options in the JPEG save dialog. But as I explained in my previous message, this one is useful so that is why I added it. Besides the option Force baseline JPEG that I removed last Friday, there are other options that could be removed in the future: - the choice of DCT method (integer, fast but less accurate integer, or floating-point) because the speed differences are not significant anymore, -- With respect Alexander Rabtchevich ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
Re: [Gimp-developer] New option Use custom quality settings for JPEG files
Date: Mon, 13 Aug 2007 10:08:27 +0200 From: =?UTF-8?B?UmFwaGHDq2w=?= Quinet [EMAIL PROTECTED] On Mon, 13 Aug 2007 09:22:58 +0200, Sven Neumann [EMAIL PROTECTED] wrote: On Sun, 2007-08-12 at 23:44 +0200, Raphaël Quinet wrote: Since Friday, I added a new option to the JPEG save dialog: Use custom quality settings. If some quantization tables were attached to the image when it was loaded, then this option allows you to use them instead of the standard ones (different quantization tables are generated by the IJG JPEG library for each quality level). Why do we need an option in the GUI for this? If there are quantization tables attached and the user doesn't change the save quality, then just use them. Or is there a real disadvantage in doing that? To me it looks like you are asking the user a question that she is unlikely going to understand. And you are forcing the user to make a decision that you can better do for her. I think that this option is still useful. Maybe not for disabling it when it is enabled, but for enabling it when it is not enabled automatically. It is usually better to use the custom quantization tables if they are better than your default quality settings. But if they are not better, then it is nice to give a choice to the user. If the quantization tables found in the original file are not better than your default quality settings, then the option Use custom quality settings will be available but not enabled. This ensures that you always get at least the minimum quality specified in your defaults. If you did not make major changes to the image and you want to save it using the same quality as the original, then you can do it by enabling this option. Would Use existing image quality settings be a better name for this? ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
Re: [Gimp-developer] New option Use custom quality settings for JPEG files
On Mon, 2007-08-13 at 11:25 +0200, Raphaël Quinet wrote: [...] - the smoothing option because this can also be performed by the usual blur filters. Actually no, I don't think it can :-) The smoothing seems to reduce jpeg artifacts quite noticeably; it appears as if it's done after decompression... although I might easily be mistaken. Liam -- Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/ Pictures from old books: http://fromoldbooks.org/ Ankh: irc.sorcery.net irc.gnome.org www.advogato.org ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
Re: [Gimp-developer] New option Use custom quality settings for JPEG files
On Mon, 2007-08-13 at 13:36 +0200, Raphaël Quinet wrote: [...] Considering that the quantization tables attached to an image would not always be the original ones, I decided to write custom instead of original for the label of that option. It is not perfect, but I have not been able to find a better description.. It sounds like Use quantization tables that are embedded in the image is what you mean? Liam -- Liam Quin - XML Activity Lead, W3C, http://www.w3.org/People/Quin/ Pictures from old books: http://fromoldbooks.org/ Ankh: irc.sorcery.net irc.gnome.org www.advogato.org ___ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
