/apng/ - Animated PNG

>>312

First i will create an APNG from a video.

Using the version of Virtual Dub that supports APNG files i will select an arbitrary timelapse from this video and export it to APNG format.

Now we will boot GIMP 2.8 and load the APNG file we created with Virtual Dub.

To do this we use the regular "Open.. " command, which will give us another dialog box.

>>317

In the dialog box that popped when trying to open a file, we need to specify the type of file we want to load.

To do this, we need to navigate to the lower left area of the box where the "Select file type" option is located.

Once you click on it, an area where you can select from several image file types will be displayed.

We need to select PNG+APNG image as our desired file type in order for it to load correctly.

Once we select it we can finally load our desired APNG file correctly.

It will load as separate layers, one for each frame you saved, this is an indicator the file opened correctly.

We can now work on the layers, play our APNG inside GIMP, optimize it, and do pretty much anything.

To test our new flashy APNG editing prowess, i performed an optimization of the APNG , which cuts down on the amount of used layers and then resized it to a smaller scale.

Next we will save our optimized and resized APNG.

BEFORE SAVING ANYTHING, THIS IS A VERY IMPORTANT STEP, YOU MUST NOT MISS

I am sure you are familiar with the layer - brushes window on GIMP, it always to the right side of the main window and it displays all the layers of the image in a list.

Well it turns this window is yet even more important for the next reason, read carefully:

the APNG plugin will cause an error when trying to save an APNG image, if the first layer in the stack is not of the size of the whole image

Now to make things clear by "the first layer", i am referring to the layer that is on the very top of the stack list.

Notice in the pictures, that the first layer is called "Frame 289", so while it may be the last frame in the animation, as long as this is on top of the stack it will be the layer that needs to meet the size condition.

Very often, APNG files produced using Virtual Dub or other program, or even made by you, will not meet this condition.

Thankfully, a very easy way to fix this is to just right click the top layer , which will cause a drop down menu to show, and select Layer to image size. Our problems are gone.

>>320

We will now proceed to save our APNG image.

To do this we will use the "Export as…" file option.

Some dialog and option boxes will pop up.

>>321

As before we will need to specify the filetype we want to save the image as.

So we will select it from the list, just like when we opened the file.

Then clicking on Export will bring up a warning "File extension does not match", we will ignore this warning and click on Save anyway, which will bring up yet again our last dialog box.

>>322

On this final step we will select from several options, the most important being the checkbox labeled As animation, should you forget to check it, you will end up with a plain PNG file without animation.

You can deselect the rest of the options and boost the compression to 9 to get a smaller file size.

Once we set our desired checkboxes we can finally click on Export and Eureka! we just saved our APNG file!

So there gentlemen, this is the result of a full night and then some daylight hours of Advanced Google-fu

I am fucking tired as hell but i managed to make this plugin work as intended.

Hopefully you guys will be able to use it better than me, because i can't seem to grasp the advantages of APNG over WEBM video, at least not in the small resolution field.

As far as i care APNG is an excellent way of optimizing gif animations tho.

See you space cowboys!

furriness was ironical

Unfortunately this plug-in (or GIMP itself) seems to still have some notable issues for APNG creation. One of which is that currently GIMP does not allow as fine of frame display control as is possible within APNG. Take a 60 FPS animation for instance. Converting this to frame display time, each frame should have 16.666… ms display. However, since GIMP's frame display only measures at the millisecond level, this must be rounded to 16ms or 17ms, creating some notable speed discrepancies.

Another option the APNG plug-in could really use is the ability to "use delay above for all frames", as the animated GIF export function has. This is useful for when you want to change the display time for all the frames in an animation at once.

Finally, it seems that you have to perform this Layer to image size step on every single undersized frame after optimizing the layers for differences or you end up with these annoying uncropped blank areas (that should be alpha channel transparency but aren't) on the margins of the undersized frames. Here's a comparison of an APNG assembled with apngasm and that same APNG opened with GIMP, optimized, and then re-saved with the APNG plug-in. I'm not sure why it's happening but additionally GIMP seems to be altering at least one of the colors in the process.

>>333

I guess the cropping issue is still present even after performing Layer to image size on every single frame.