32394 - Animated GIF stops

Status: VERIFIED INVALID

(Core :: Graphics: ImageLib, defect, P2)

Description

[Eugene Savitsky]

Animated GIF stopps (like in Netscape 4.7x). The gif is created with "Animagic 
GIF".

Comment 1

[Richard Zach]

Guessing ImageLib.

The page contains two animated GIfs (rainbow flag).  On my NS 4.7, the left one
is animated, the right one stops after a second or so (one cycle?).  On Mozilla,
both are static.

ezh, are both supposed to be continuously animated?

Comment 2

[Eugene Savitsky]

Both are continuously animated. This page describes that in NN 4.04 all looks 
ok, but when the owner of the page moved to NN 4.7 he has discovered this 
effect.

In Mozilla (like in NN 4.7x) the right one animate's too, but just for once 
(should be looped, like the left one). It was created with "Animagic 
GIF".

Comment 3

[neeti]

Moving to m17

Comment 4

[neeti]

Changing priority to P2.

Comment 5

[neeti]

Moving to m18

Comment 6

[tenthumbs]

Animagic sometimes makes corrupt animated GIFs. It will add a null byte
between the last data block and the trailer byte. For the problem GIF
above (rainbow2.gif), here's the tail of a hex dump.

1a10  4d f4 00 83 08 42 b8 20  44 13 4d 1c 54 45 13 34
1a20  74 20 81 0b 34 5b 21 f2  45 38 e7 4c 50 40 00 00
1a30  3b                                            ^^
                                                    ||

The marked byte is the problem. 

Most of my Linux software complains about an unknown data block type in
the GIF. I'm guessing that Mozilla (and 4.x as well) is equally upset
and gives up when it reaches it. If you remove the byte then the GIF
works as expected.

The only real question is whether Mozilla should try to handle this.

Comment 7

[Jesse Ruderman]

ok, so should this bug be "fixed" and a new bug filed to complain once bug 6211 
is implemented, or should this bug be changed to "should complain about 
corrupted gifs" and marked as depending on bug 6211?

Comment 8

[pnunn]

I think mozilla is handling this fairly gracefully.
It displays as much of the corrupted gif as possible
and then stops.
I'm marking closed/invalid since the problem is in 
the image. The page owner, could use 2 instances of
rainbow1.gif if they were bothered by the animation
stopping when it hits the corrupted portion.

-P

Comment 9

[Eli Goldberg]

Rubber-stamping as verified/invalid. Thanks, Tenthumbs & Eugene!