7 ms·

>As you probably know, GIF is limited to a palette of 256 colors. No, it's not. OK, the current, wrong, implementations do limit it to 256 colors, but that's n

by 1ris 12y ago

>As you probably know, GIF is limited to a palette of 256 colors. No, it's not. OK, the current, wrong, implementations do limit it to 256 colors, but that's not a limitation of gif. Mulitple frames without a delay allow multiple pallets and multiple times 265 colors. But this limitation is just another reason not to use it. Can I use Webm? http://caniuse.com/#feat=webm http://caniuse.com/#feat=webm Yes, you can, and you should. Or h.264: http://caniuse.com/#feat=mpeg4 http://caniuse.com/#feat=mpeg4

ux 12y ago
Can you show an example of an animation with more than 256 colors? As you said, the hack to get more than 256 colors is to redefine a sub rectangle with a new palette. But that's also the mechanism used to make animations. Are you able to get fluid playback with that? Note: I'm not talking about new frame being just a new sub rectangle, more about N sub rectangles for the same frame, then a delay event, then M sub rectangles for the new frame, etc
- 1ris 12y ago
  None that works with current browsers implantations, because they erroneous ignore no delay between frames and wait anyway. But that's a bug in the gif decoder, not a limitation of gif. OK, this is hairsplitting, but it illustrates how borken the state of gif is.
  - eridius 12y ago
    Maybe someone who cares about this should submit patches? All of the major browser engines are open-source.
    - chc 12y ago
      This would probably cause regressions with other GIFs that neglect to specify a delay but are supposed to have one. It's hard to imagine this universal behavior is accidental. It's probably like everything else on the Web — a hack to keep things that shouldn't work from actually not working.
      - wzdd 12y ago
        I'm fairly sure that the reason for this universal behaviour is that there are plenty of broken, looping gifs out there with inter-frame delays of 0. I used a version of Konqueror which would spin at 100% of a core when it encountered one of these. A better hack (but it's still a hack) might be to wait one frame (or longer) before returning to the beginning of a looping gif. Given that this would be significantly harder than the current approach (which is apparently either delay = max(delay, 16ms) or if(delay < 16) delay = 100) and the only reason for it would be to support this pretty-niche multi-palette composited-frame thing, it seems like it would be hard to argue for.
      - eridius 12y ago
        Are there GIFs that specify a delay on some frames but not others, and expect all frames to have a delay? Because it should be easy to detect animated GIFs that specify no delay for any frame, and treat them all as having a delay.
        chc 12y ago
        As I understand it, that would still block this "large-palette GIF" trick, because those would also consist entirely of frames with no delay.
        eridius 12y ago
        I assumed that the "large-palette GIF" would have animation. Otherwise, why are you bothering with tricky GIFs at all, why not just use a PNG (or JPEG, depending on the image type)?
        neolefty 12y ago
        A workaround for the workaround: for a high-color gif, add a blank "animation" frame at the end that has a delay, after all the no-delay buildup elements. However, that's unlikely to be necessary because if you are just doing a high-color image with no animation, you may as well use JPEG or PNG.
    - mbrubeck 12y ago
      > All of the major browser engines are open-source. In a world where Internet Explorer is not a major browser.
      - eridius 12y ago
        Hah, I can't believe I actually forgot Internet Explorer was still around. Good point.
  - ChrisLomont 12y ago
    Actually, regarding the delay, the spec reads "vii) Delay Time - If not 0, this field specifies the number of hundredths (1/100) of a second to wait before continuing with the processing of the Data Stream. " A zero delay is most certainly not covered by the spec, and anyone using one is creating GIFs that do not meet the spec. [0] http://www.w3.org/Graphics/GIF/spec-gif89a.txt http://www.w3.org/Graphics/GIF/spec-gif89a.txt
    - bbllee 12y ago
      You can achieve no delay without using a zero delay. Graphic Control Extension blocks may be omitted between images and so multiple images can come in a row without anything defining a delay between them. See the last instance of the phrase "graphic control" in the document to see that multiple images can come with no intervening GCE blocks and see the paragraph containing the 5th instance of that phrase to observe that a GCE block only affects the first image following the GCE.
deleted 12y ago
[deleted]
wukerplank 12y ago
While GIF is surely inferior to short looped videos, it's still ahead in terms of usability/portability: Drag & drop the file to the desktop and re-upload elsewhere (or embed in your own website). AFAIK this experience is unmatched by web video.
- 1ris 12y ago
  Global support for h.264 video in the browser: over 90%. And on the desktop it's close to 100%. That's IMO just good enough.
  - wukerplank 12y ago
    That's not what I was referring to. Yes, technically videos are superior, no doubt. The nice thing about GIFs is though that they are treated like images by the browser and the OS. That makes them easier to handle by non-technical users (think imgur, Tumblr, etc.).
    - acdha 12y ago
      .mp4 is also well supported by modern operating systems. The only place where there's a problem would be a website which allows you to upload images but not videos. I'm inclined to say that the enormous compression wins are worth getting the remaining stragglers to upgrade (both of the sites you mentioned already do this, for example, as do other common targets like Twitter, Facebook, etc.).
    - 1ris 12y ago
      I just realised that imgur does not support webm. I thought it does. Thats kind of stupid. For other websites it'd be as simple as adding a mime type to the list of accepted uploads. Unfortunalty you are right, right now webm is still exotic.
      - voltagex_ 12y ago
        The silly thing is if you have a gif and change the URL on imgur to read ".gifv" you'll get WebM!
erikano 12y ago
Don't forget Ogg/Theora. http://caniuse.com/#feat=ogv http://caniuse.com/#feat=ogv

by 1ris 12y ago

ux 12y ago

Can you show an example of an animation with more than 256 colors? As you said, the hack to get more than 256 colors is to redefine a sub rectangle with a new palette. But that's also the mechanism used to make animations. Are you able to get fluid playback with that? Note: I'm not talking about new frame being just a new sub rectangle, more about N sub rectangles for the same frame, then a delay event, then M sub rectangles for the new frame, etc

1ris 12y ago
None that works with current browsers implantations, because they erroneous ignore no delay between frames and wait anyway. But that's a bug in the gif decoder, not a limitation of gif. OK, this is hairsplitting, but it illustrates how borken the state of gif is.
- eridius 12y ago
  Maybe someone who cares about this should submit patches? All of the major browser engines are open-source.
  - chc 12y ago
    This would probably cause regressions with other GIFs that neglect to specify a delay but are supposed to have one. It's hard to imagine this universal behavior is accidental. It's probably like everything else on the Web — a hack to keep things that shouldn't work from actually not working.
    - wzdd 12y ago
      I'm fairly sure that the reason for this universal behaviour is that there are plenty of broken, looping gifs out there with inter-frame delays of 0. I used a version of Konqueror which would spin at 100% of a core when it encountered one of these. A better hack (but it's still a hack) might be to wait one frame (or longer) before returning to the beginning of a looping gif. Given that this would be significantly harder than the current approach (which is apparently either delay = max(delay, 16ms) or if(delay < 16) delay = 100) and the only reason for it would be to support this pretty-niche multi-palette composited-frame thing, it seems like it would be hard to argue for.
    - eridius 12y ago
      Are there GIFs that specify a delay on some frames but not others, and expect all frames to have a delay? Because it should be easy to detect animated GIFs that specify no delay for any frame, and treat them all as having a delay.
      - chc 12y ago
        As I understand it, that would still block this "large-palette GIF" trick, because those would also consist entirely of frames with no delay.
        eridius 12y ago
        I assumed that the "large-palette GIF" would have animation. Otherwise, why are you bothering with tricky GIFs at all, why not just use a PNG (or JPEG, depending on the image type)?
      - neolefty 12y ago
        A workaround for the workaround: for a high-color gif, add a blank "animation" frame at the end that has a delay, after all the no-delay buildup elements. However, that's unlikely to be necessary because if you are just doing a high-color image with no animation, you may as well use JPEG or PNG.
  - mbrubeck 12y ago
    > All of the major browser engines are open-source. In a world where Internet Explorer is not a major browser.
    - eridius 12y ago
      Hah, I can't believe I actually forgot Internet Explorer was still around. Good point.
- ChrisLomont 12y ago
  Actually, regarding the delay, the spec reads "vii) Delay Time - If not 0, this field specifies the number of hundredths (1/100) of a second to wait before continuing with the processing of the Data Stream. " A zero delay is most certainly not covered by the spec, and anyone using one is creating GIFs that do not meet the spec. [0] http://www.w3.org/Graphics/GIF/spec-gif89a.txt http://www.w3.org/Graphics/GIF/spec-gif89a.txt
  - bbllee 12y ago
    You can achieve no delay without using a zero delay. Graphic Control Extension blocks may be omitted between images and so multiple images can come in a row without anything defining a delay between them. See the last instance of the phrase "graphic control" in the document to see that multiple images can come with no intervening GCE blocks and see the paragraph containing the 5th instance of that phrase to observe that a GCE block only affects the first image following the GCE.

deleted 12y ago

[deleted]

wukerplank 12y ago

While GIF is surely inferior to short looped videos, it's still ahead in terms of usability/portability: Drag & drop the file to the desktop and re-upload elsewhere (or embed in your own website). AFAIK this experience is unmatched by web video.

1ris 12y ago
Global support for h.264 video in the browser: over 90%. And on the desktop it's close to 100%. That's IMO just good enough.
- wukerplank 12y ago
  That's not what I was referring to. Yes, technically videos are superior, no doubt. The nice thing about GIFs is though that they are treated like images by the browser and the OS. That makes them easier to handle by non-technical users (think imgur, Tumblr, etc.).
  - acdha 12y ago
    .mp4 is also well supported by modern operating systems. The only place where there's a problem would be a website which allows you to upload images but not videos. I'm inclined to say that the enormous compression wins are worth getting the remaining stragglers to upgrade (both of the sites you mentioned already do this, for example, as do other common targets like Twitter, Facebook, etc.).
  - 1ris 12y ago
    I just realised that imgur does not support webm. I thought it does. Thats kind of stupid. For other websites it'd be as simple as adding a mime type to the list of accepted uploads. Unfortunalty you are right, right now webm is still exotic.
    - voltagex_ 12y ago
      The silly thing is if you have a gif and change the URL on imgur to read ".gifv" you'll get WebM!

erikano 12y ago

Don't forget Ogg/Theora. http://caniuse.com/#feat=ogv http://caniuse.com/#feat=ogv