How to extract frames as bitmap from webp

[KishorJena]

Hi, please help me to decode animated webp frame by frame. I want to resize each bitmaps and later encode them into webp image file. This is not for drawing on image views. I just want to get file from local and save it to local storage.
I tried ImageMagick CLI it was working fine but it's android binding does not cover all the functionality of imagemgaick so I had to remove it. ffmpeg does not have animated decoder. After googling and exploring forums I came to here,I read that coil has animated webp decoder. At least give a pseudo code that it is possible in coil so that I will start implementing.

[rishabhhgupta]

so late i got this solution

[rishabhhgupta]

it's only have encoder no decoder, all i need is to get all the bimap arraylist of webp, each frame rate and total Duration, only solution i think i have is use webplib which is written in c/c++ that i have to import in my android studio and i didn't have experience of c/c++, as you say you create decoder but i didn't find , how i decode the animated webp file

[rishabhhgupta]

Yeah I stopped coding related to webp encoder decoder. Now i remember that the PR was just to implement the alpha channel to preserve the transparency of animated webp images. and later published the decoder encoder on my github as I have made major changes in encoder as well and wrote decoder codes. Webp_Transcoder usage:

       WebpAnimatedDecoder deocder = new WebpAnimatedDecoder(new File(inFile));
       List<ProcessedFrames> processedFrames = deocder.decode();

       // collect all frames as bitamsp here.
       List<Bitmap> bitmaps = new ArrayList<>();

       for(int i = 0; i < processedFrames.size()-1; i++){
           ProcessedFrames processedFrame = processedFrames.get(i);
           Bitmap bitmap = processedFrame.bitmap;
           bitmaps.add(bitmap);
       }
      

Earlier I have also thought that its only possible using c/cpp or need to write jni by placing cpp codec by google. But later I have achieved to extract frames as bitamsp and also encode them back to webp aniamted image using JAVA only. I followed the WEBP container specification docs and modified the b4rtaz/android-webp-encoder

Also found another way with Glide . And built react native module for image transformation which requires decoding and encoding both. react-native-image-file-transformer

I have answer in case any body going through same issues about decoding encoding webp images.

Lol you private your repo, Your answer took so long i use libwebp(c/cpp) in my android studio project and it work preety well. thank you for your response