gif2webp: force low duration frames to 100ms

this is consistent with web browser behavior as well as various
transcoding tools (ffmpeg, gif2apng, etc).

also: update anim_diff to account for this new behaviour.

BUG=webp:379

Change-Id: I70cc72a6b401ef32b73cd182a3f12d993d495bf4
This commit is contained in:
James Zern
2018-03-23 22:48:17 -07:00
committed by Pascal Massimino
parent b2db361ca6
commit 09333097ed
2 changed files with 11 additions and 0 deletions

View File

@ -593,6 +593,9 @@ static int ReadAnimatedGIF(const char filename[], AnimatedImage* const image,
curr_frame = &image->frames[i];
curr_rgba = curr_frame->rgba;
curr_frame->duration = GetFrameDurationGIF(gif, i);
// Force frames with a small or no duration to 100ms to be consistent
// with web browsers and other transcoding tools (like gif2webp itself).
if (curr_frame->duration <= 10) curr_frame->duration = 100;
if (i == 0) { // Initialize as transparent.
curr_frame->is_key_frame = 1;