webp-container-spec: correct frame duration=0 note

the interpretation of a 0 duration depends on the implementation;
merging of multiple frames isn't guaranteed, some may enforce a minimum
duration.

BUG=webp:380

Change-Id: Idf592049d2092e4cc5cfb2e4c59ddbc91bd52f9c
This commit is contained in:
James Zern 2018-04-20 12:59:50 -07:00
parent fd3d5756cb
commit 71c39a06c8

View File

@ -446,8 +446,9 @@ Frame Height Minus One: 24 bits (_uint24_)
Frame Duration: 24 bits (_uint24_)
: The time to wait before displaying the next frame, in 1 millisecond units.
In particular, frame duration of 0 is useful when one wants to update
multiple areas of the canvas at once during the animation.
Note the interpretation of frame duration of 0 (and often <= 10) is
implementation defined. Many tools and browsers assign a minimum duration
similar to GIF.
Reserved: 6 bits