webp compression

[0xNima]

Hi Peter. First of all I want to thank you to developing this helpful tool. I have a question about the reducing of webp file size without changing the dimension. I want to convert Telegram animated sticker to WhatsApp sticker but it has a limitation of max 500kb file size. Do you know any method to do this?

[PeterMX]

Hi, using -q 0 will reduce quallity and you will get smaller webps, but it will no be enought to get 500kb, with a small change in render.cpp in the for loop you can skip some frames and that will help you get those 500kb or smaller.

[0xNima]

Hi again Peter. Now I can reduce the final size by skipping some frames and check the webp_data size and repeat again until to reach the desired size. The reason that I use this approach is that I want to remove less frames as much as possible.
I notice that in this approach, frames recalculated in each iteration. I tried to memoize the calculated frames by storing pic (in the addFrame method) in a map but it doesn't work.
Do you have any suggestion to cache the calculated frames?

[PeterMX]

Hi, No, I don't know how to cache pic,
on the other hand, in your code you set 500000 as max size but it should be 512000(as said in Whatsapp repo), 12000 bytes is big enought to miss some valid stickers