iLiad Introducing the new Sony-Reader-speed ipdf - Page 2

scotty1024 · 10-26-2006, 08:58 PM

Quote:

Originally Posted by Mike Kostousov

Hmm... Something is going wrong. I think - bytes_per_line in XImage rendering a bit less, that we realy need. I get such shifting on several pdfs... Including iRex release notes

One of the things I inherited was a setting to Splash that I think is padding the lines to a 4 byte boundary. I'm going to set it to 1 and see what happens, after I have dinner.

Mike Kostousov · 10-26-2006, 09:15 PM

When I was playing with xpdf, I've found that non-24bits splash doesn't work properly with several pdf. For example, 32bits splash (it could be very useful for construct QImage, directly from Splash) didn't render color background well. I don't know why. But, may be I was wrong, may be xpdf was wrong and now it is fixed in poppler. May be iRex guys didn't look deep inside...

scotty1024 · 10-26-2006, 09:34 PM

It was exactly what I thought it was.

Padding is now set to 1 and all is happiness.

My next performance tweak is my Famous Jack Rabbit Performance Test.

scotty1024 · 10-26-2006, 09:39 PM

Quote:

Originally Posted by Mike Kostousov

When I was playing with xpdf, I've found that non-24bits splash doesn't work properly with several pdf. For example, 32bits splash (it could be very useful for construct QImage, directly from Splash) didn't render color background well. I don't know why. But, may be I was wrong, may be xpdf was wrong and now it is fixed in poppler. May be iRex guys didn't look deep inside...

If you have one of those PDF's lying around please test it on the newly enhanced ipdf and let me know how it works?

I'm off to put in an hour on the promised idjvu viewer.

DHer · 10-27-2006, 12:43 AM

Scotty, you are doing magic.

I can't wait for this day to end, so i can spend some quality time with my iliad and your releases.

scotty1024 · 10-27-2006, 01:39 AM

Quote:

Originally Posted by DHer

Scotty, you are doing magic.

I can't wait for this day to end, so i can spend some quality time with my iliad and your releases.

Thank you and enjoy the code when you get home! My wife has been accusing me of giggling as I sit there flipping pages on my iLiad. Its really just "fast enough" now.

I just sent an electronic package off to iRex and I'm heading for bed myself.

tribble · 10-27-2006, 03:06 AM

scotty, i hope iRex will use your code really quick. Cant wait to see it myself.

Thanks for your hard work.

Matthijs · 10-27-2006, 03:48 AM

This looks very interesting, however:

The reason why we stuck to RGB rendering (yes, we did try this Mono8 too) is that now images inside the PDF document that were in color will look ugly (they show 'banding', take a look at the first page of the iLiad User Manual for an example).

If this dithering inside libpoppler can be fixed, we can have another look at this approach.

It was also reported by one of our engineers that some of the smaller fonts actually look LESS sharp in 8bit grey. But that is of course hard to compare with only 1 iLiad...

As for the speed: going from page to page uses pre-rendering and is not affected by the changes above. Only the actual rendering of pages uses more memory and is slower in 'our' implementation, but pushing the resulting XImage to the screen (which is all that is done when a page is flipped) is equally fast. Startup time of the viewer and rendering of a page that is not pre-rendered is faster of course.

In summary: there are outstanding problems to be fixed. Dithering of color-images in Mono8 mode in libpoppler needs adjustment for the iLiad color-space, that is a very important one.

We really hope that by working together with the community on these kind of things, we can bring the iLiad software to the next level even faster.

Thank you all for contributing, please continue to do so.

Matthijs van de Water
Embedded Software Engineer
iRex Technologies BV

emkay · 10-27-2006, 04:25 AM

Matthijs,
I think your attitude is really great. This collaboration with the developer community is really going to pay off for everybody, iRex and iLiad users.
Well done iRex! Well done Scotty and other developers!

Matthijs · 10-27-2006, 04:33 AM

I've just had another look at the code:

What we need to add (inside ipdf) is the Floyd-Steinberg dithering that was there before, but now on the 8bit greyscale image. The implementation of that algorithm in greyscale should be easier than the one that was used to convert from RGB24 to 8bit greyscale including dithering.

You should understand that the iLiad does a linear conversion from 256 grey levels to 16 grey levels on a device-driver level (so the first 16 levels of grey become white, etc.).

Maybe Scotty can have a look at this when he wakes up

Mambo · 10-27-2006, 06:08 AM

Matthijs:

I think the majority of users would be more happy with faster rendering than with nice looking colour PDF images. Anyway we have only 16 colours.

I have PDF documents that take more than 16 seconds to render sometimes. Even if I read in sequential order, sometimes I want to skip pages and flip them over, when prerendering just fails.

Actually in the iLiad settings there should be a switch: faster PDF viewing or better looking images. The user can choose which one he wants.

please give the user choices! It will not make this device overly difficult to use! It is up to you whether you go into the settings or not, and also you could any time go back to default as an option, this way there would be nothing to worry about.

I can not see why this would be a problem.

CommanderROR · 10-27-2006, 06:39 AM

I think the idea with the "options" would be nice, but if you take a long-term view, it will get confusing because every user has his/her own ideas and you would probably end up including more options than any single and sane person could ever want...:-)

I do however believe that we should get a choice of using Scotty's new PDF viewer if we want to. For me it wouldn't be a problem if there were some display errors in the pictures, because I use text-PDF files only, the maximum in image-display being a frontcover and maybe a map in most cases. I also founf that the curretn implementation doesn't really convert colours to grey all that well anyway so I started converting my PDf files to greyscale before I transfer them to the Iliad, thus also reducing file-size...

Matthijs · 10-27-2006, 06:40 AM

Basically making a setting configurable through the settings application takes up valuable development resources. It sounds simple, but it actually takes quite some work (GUI, libraries, testing).

What I'm suggesting is taking a little time to implement the Floyd-Steinberg algorithm for 16 levels of grey and have 1 single solution which is both faster and has good-looking images.

jæd · 10-27-2006, 06:43 AM

Quote:

Originally Posted by Mambo

please give the user choices! It will not make this device overly difficult to use! It is up to you whether you go into the settings or not, and also you could any time go back to default as an option, this way there would be nothing to worry about.

Perhaps if there are two viewers for a format a "Open with...?" dialog would be handy. That way the user can choose whether he wants fast pages or nice pictures...

emkay · 10-27-2006, 07:11 AM

I think Matthjis is suggesting that with tweaking we could have fast pages which also look nice. I suggest we focus everybody's effort on making one great PDF viewer, instead of having various viewers with different strengths...
(For the moment anyway. I know there should be more software options further down the line.)

10-26-2006, 09:15 PM	#17
Mike Kostousov Connoisseur Posts: 50 Karma: 861 Join Date: Aug 2006 Device: Zaurus C1000/iLiad/SE K750i	When I was playing with xpdf, I've found that non-24bits splash doesn't work properly with several pdf. For example, 32bits splash (it could be very useful for construct QImage, directly from Splash) didn't render color background well. I don't know why. But, may be I was wrong, may be xpdf was wrong and now it is fixed in poppler. May be iRex guys didn't look deep inside... Last edited by Mike Kostousov; 10-26-2006 at 09:17 PM.

10-27-2006, 03:48 AM	#23
Matthijs Groupie Posts: 199 Karma: 666 Join Date: Oct 2006 Location: Eindhoven, the Netherlands Device: iLiad, DR1000S, DR800SG	There is always a but... This looks very interesting, however: The reason why we stuck to RGB rendering (yes, we did try this Mono8 too) is that now images inside the PDF document that were in color will look ugly (they show 'banding', take a look at the first page of the iLiad User Manual for an example). If this dithering inside libpoppler can be fixed, we can have another look at this approach. It was also reported by one of our engineers that some of the smaller fonts actually look LESS sharp in 8bit grey. But that is of course hard to compare with only 1 iLiad... As for the speed: going from page to page uses pre-rendering and is not affected by the changes above. Only the actual rendering of pages uses more memory and is slower in 'our' implementation, but pushing the resulting XImage to the screen (which is all that is done when a page is flipped) is equally fast. Startup time of the viewer and rendering of a page that is not pre-rendered is faster of course. In summary: there are outstanding problems to be fixed. Dithering of color-images in Mono8 mode in libpoppler needs adjustment for the iLiad color-space, that is a very important one. We really hope that by working together with the community on these kind of things, we can bring the iLiad software to the next level even faster. Thank you all for contributing, please continue to do so. Matthijs van de Water Embedded Software Engineer iRex Technologies BV Last edited by Matthijs; 10-27-2006 at 03:51 AM.

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10-27-2006, 12:43 AM	#20
DHer Addict Posts: 261 Karma: 156 Join Date: Jul 2006 Device: iliad	Scotty, you are doing magic. I can't wait for this day to end, so i can spend some quality time with my iliad and your releases.

10-27-2006, 03:06 AM	#22
tribble iLiad Maniac Posts: 1,382 Karma: 2369 Join Date: Apr 2006 Location: Germany Device: Bookeen Opus (i love that thing) and iPad (what an irony)	scotty, i hope iRex will use your code really quick. Cant wait to see it myself. Thanks for your hard work.

10-27-2006, 04:25 AM	#24
emkay Zealot Posts: 103 Karma: 11 Join Date: Jul 2006	Matthijs, I think your attitude is really great. This collaboration with the developer community is really going to pay off for everybody, iRex and iLiad users. Well done iRex! Well done Scotty and other developers!

10-27-2006, 04:33 AM	#25
Matthijs Groupie Posts: 199 Karma: 666 Join Date: Oct 2006 Location: Eindhoven, the Netherlands Device: iLiad, DR1000S, DR800SG	I've just had another look at the code: What we need to add (inside ipdf) is the Floyd-Steinberg dithering that was there before, but now on the 8bit greyscale image. The implementation of that algorithm in greyscale should be easier than the one that was used to convert from RGB24 to 8bit greyscale including dithering. You should understand that the iLiad does a linear conversion from 256 grey levels to 16 grey levels on a device-driver level (so the first 16 levels of grey become white, etc.). Maybe Scotty can have a look at this when he wakes up

10-27-2006, 06:08 AM	#26
Mambo Gadget fan Posts: 147 Karma: 3968 Join Date: Sep 2006 Location: London Device: RM Tablet PC, iLiad, PRS 505, iPod Touch	Matthijs: I think the majority of users would be more happy with faster rendering than with nice looking colour PDF images. Anyway we have only 16 colours. I have PDF documents that take more than 16 seconds to render sometimes. Even if I read in sequential order, sometimes I want to skip pages and flip them over, when prerendering just fails. Actually in the iLiad settings there should be a switch: faster PDF viewing or better looking images. The user can choose which one he wants. please give the user choices! It will not make this device overly difficult to use! It is up to you whether you go into the settings or not, and also you could any time go back to default as an option, this way there would be nothing to worry about. I can not see why this would be a problem.

10-27-2006, 06:39 AM	#27
CommanderROR eink fanatic Posts: 2,022 Karma: 4924 Join Date: Mar 2006 Location: Germany Device: STAReBOOK, iRex Iliad, Sony 505, Kindle 2	I think the idea with the "options" would be nice, but if you take a long-term view, it will get confusing because every user has his/her own ideas and you would probably end up including more options than any single and sane person could ever want...:-) I do however believe that we should get a choice of using Scotty's new PDF viewer if we want to. For me it wouldn't be a problem if there were some display errors in the pictures, because I use text-PDF files only, the maximum in image-display being a frontcover and maybe a map in most cases. I also founf that the curretn implementation doesn't really convert colours to grey all that well anyway so I started converting my PDf files to greyscale before I transfer them to the Iliad, thus also reducing file-size...

10-27-2006, 06:40 AM	#28
Matthijs Groupie Posts: 199 Karma: 666 Join Date: Oct 2006 Location: Eindhoven, the Netherlands Device: iLiad, DR1000S, DR800SG	Basically making a setting configurable through the settings application takes up valuable development resources. It sounds simple, but it actually takes quite some work (GUI, libraries, testing). What I'm suggesting is taking a little time to implement the Floyd-Steinberg algorithm for 16 levels of grey and have 1 single solution which is both faster and has good-looking images.

10-27-2006, 07:11 AM	#30
emkay Zealot Posts: 103 Karma: 11 Join Date: Jul 2006	I think Matthjis is suggesting that with tweaking we could have fast pages which also look nice. I suggest we focus everybody's effort on making one great PDF viewer, instead of having various viewers with different strengths... (For the moment anyway. I know there should be more software options further down the line.)

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