Can jpg images support animation?

jpeg image

How is the above jpg image animat开发者_开发问答ed? As far as I know jpg format does not support animation.

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No, the JPEG file format has no inherent support for animation.

The image you linked is actually an animated GIF disguised with a jpg file extension. (The browser apparently ignores even the MIME type and looks at the file header bytes in such cases.)

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If you view the image in firefox, you can right-click on it and select properties:

You'll see Type: GIF image (animated, 54 frames)

Thus, it is a gif-image that has been renamed to .jpg.

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For completeness, I'd like to point our that there's Motion-JPEG - sort of a jpg animation.

MJPEGs, usually produced by webcams, are a stream of JPEG files concatenated together, one after another, sometimes delimited by a HTTP header, and served by webcam-webservers with a MIME-Type of multipart/x-mixed-replace;boundary=, where boundary= defines the delimiter.

A search for animated JPEG related projects on github results in two findings:

1. In case people care about the size of an animated GIF, they strip it into separate JPG frames and tell the browser to exchange these frames in-place via some JavaScript code. For example. (Pawel's answer)

2. Then there's actually a proposed Animated JPEG standard, which stems from MJPEG and declares framerate and so forth in each JPG frame. Not probable to arrive in browsers anytime soon.

And lastly, I've seen image-hosters to replace large animated GIFs with a mp4 version of the GIF for presentation, plus some Javascript to serve the actual GIF for downloads/non-supported browsers.

And no, JPEG itself, via JFIF, does not offer a facility to animate a JPG file in itself, just as Noldorin already noted in the chosen answer. :shrug:

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It is a GIF image... the extension has been changed by hand. Browser engine is smart enough to determine image format regardless of file extension.

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var c = 1;

/* Preloading images */
var image1 = new Image();
image1.src = "a1.jpg";
var image2 = new Image();
image2.src = "a2.jpg";
var image3 = new Image();
image3.src = "a3.jpg";
var image4 = new Image();
image4.src = "a4.jpg";
var image5 = new Image();
image5.src = "a5.jpg";

function disp_img(w)
   {
   if (c == 6)
      {
      c = 1;
      }
   var img_src = "a" + c + ".jpg";
   document.ani.src = img_src;
   c++;
   }
t = setInterval("disp_img(c)", 1000);

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No JPEG doesn't support animation. Saving a GIF file with .jpeg extension doesn't male it a JPEG file. It's still a GIF file. Because OS Image viewer doesn't look into file extension it rather looks into the content.

If you open that file as binary (in a text editor) you will see the first line contains GIF89ad�d�˜|� Which is the magic number for GIF.

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Yes, you can make animation using single jpeg. Google "jpeg css sprites". Of course this will not be native animation support by jpeg format.

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A bit of a necro-post but since this question popped first when I tried to get info about pixel motion jpeg, here's some additional info.

Since Pixel2, Google created motion jpeg, which is an ordinary jpeg at the end of which there's an mp4 video. More on this here:

https://android.jlelse.eu/working-with-motion-photos-da0aa49b50c

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JPG does not animate. You either saw a series of JPG images rendered with javascript or you saw a GIF file named as a JPG. A web server and browser might still recognize the correct GIF filetype, even if the wrong extension has been added to the filename.

If you open the image file and if it is a sort of GIF format by using a hex editor, you see the following 4 bytes designating that image type is of GIF.