Mozilla Firefox added support for APNG in version 3 trunk builds on March 23, 2007. There have been several subsequent proposals for a simple animated graphics format based on PNG using several different approaches. The PNG group officially rejected APNG as an official extension on April 20, 2007. apng, leading to the format not being approved by the PNG Development Group. Glenn Randers-Pehrson spearheaded efforts to reconcile the PNG purists' position with that of APNG proponents by recommending changes to APNG's format and proposing the use of a unique MIME type (e.g., video/png), but the APNG proponents only added the different MIME type (image/apng) while insisting on the use of the. Some of the main concerns arising from this were the inability of applications to negotiate for PNG and APNG, or distinguish between PNG and APNG once received, or for legacy software to even inform users that there are additional frames. APNG hides the subsequent frames in PNG ancillary chunks in such a way that APNG-unaware applications would ignore them, but there are otherwise no changes to the format to allow software to distinguish between animated and non-animated images. In particular, PNG was conceived to be a single-image format. In May 2003, Mozilla had scrapped support for MNG animations, which provides a superset of APNG functionality, citing concerns about the large file size required for the expansive MNG decoder library (300 KB) the APNG decoder, built on the back of the PNG decoder, was a much smaller component.Īmong users and maintainers of the PNG and MNG formats, APNG had a lukewarm reception.
The APNG specification was created in 2004 by Stuart Parmenter and Vladimir Vukićević of the Mozilla Corporation to allow for storing the animations needed for interfaces such as throbbers. In a comparison made between GIF, APNG and lossless WebP, APNG had the lowest file size.
APNG's advantage was the smaller library size and compatibility with older PNG implementations.
APNG competed with Multiple-image Network Graphics (MNG), a comprehensive format for bitmapped animations which was created by the same team as PNG and is obsolete. The frame speed data and extra animation frames are stored in extra chunks (as provided for by the original PNG specification). The first frame of an APNG file is stored as a normal PNG stream, so most standard PNG decoders are able to display the first frame of an APNG file. It also retains backward compatibility with non-animated PNG files. Image/, image/apng, image/pngĪnimated Portable Network Graphics ( APNG) is a file format which extends the Portable Network Graphics (PNG) specification to permit animated images that work similarly to animated GIF files, while supporting 24-bit images and 8-bit transparency not available for GIFs.
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