« Return to Thread: Re: APNG MIME type and extension
Re: APNG MIME type and extension
by glennrp-2
::
Rate this Message:
At 08:45 AM 3/16/2007 -0400, Adeluc wrote:
>> From: Vladimir Vukicevic
>The only way to "better" respect the PNG specs is to have only 1 big image
>composed of many subimages. The aCTL chunk indicates the real size of the
>animation target rectangle and the loop count. Each followed fCTL chunk
>contains the usual stuff, a frame number and indicates the subrectangle
>containing the frame image from the big image. The fCTL chunks do not need
>to be in order. Subrectangles can have different sizes and overlap (if two
>frames are identical then they can share the same subrectangle), opening the
>possibility to create great animation effects with ridiculous small file
>size. Since all the fCTL chunks come before the IDAT, an infinite loop
>animation may begin immediately when first IDAT chunk is read so interlacing
>animation is also supported (animation detail quality increases over time).
This is an interesting proposal and in fact is how I made some of the
early MNG demos that are on the MNG ftp site. They contain one wide
image that is viewed one piece at a time, like a film strip. This
lets the deflate compressor take advantage of the frame-to-frame
redundancy. If we were to define a PNG-2 with limited animation
capability, I think it would have at least this capability. But it
does not seem suitable for APNG because the fall-back frame would
be a montage instead of a single picture (even though it is a
single image) and would be too big.
Glenn
-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
png-mng-misc mailing list
png-mng-misc@...
https://lists.sourceforge.net/lists/listinfo/png-mng-misc
>> From: Vladimir Vukicevic
>The only way to "better" respect the PNG specs is to have only 1 big image
>composed of many subimages. The aCTL chunk indicates the real size of the
>animation target rectangle and the loop count. Each followed fCTL chunk
>contains the usual stuff, a frame number and indicates the subrectangle
>containing the frame image from the big image. The fCTL chunks do not need
>to be in order. Subrectangles can have different sizes and overlap (if two
>frames are identical then they can share the same subrectangle), opening the
>possibility to create great animation effects with ridiculous small file
>size. Since all the fCTL chunks come before the IDAT, an infinite loop
>animation may begin immediately when first IDAT chunk is read so interlacing
>animation is also supported (animation detail quality increases over time).
This is an interesting proposal and in fact is how I made some of the
early MNG demos that are on the MNG ftp site. They contain one wide
image that is viewed one piece at a time, like a film strip. This
lets the deflate compressor take advantage of the frame-to-frame
redundancy. If we were to define a PNG-2 with limited animation
capability, I think it would have at least this capability. But it
does not seem suitable for APNG because the fall-back frame would
be a montage instead of a single picture (even though it is a
single image) and would be too big.
Glenn
-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
png-mng-misc mailing list
png-mng-misc@...
https://lists.sourceforge.net/lists/listinfo/png-mng-misc
« Return to Thread: Re: APNG MIME type and extension
| Free embeddable forum powered by Nabble | Forum Help |
