Legacy ImageMagick Discussions Archive

hi all

i'm using imagemagick with C++. i have couple of questions regarding gif creation. i create a gif like the following code:

Code: Select all

std::vector<Magick::Image> frames;

for (int i = 0; i < fromImages.size(); ++i) {
    Magick::Image img = fromImages[i].getImage();
    img.animationDelay(10);
    img.compressType(Magick::LZWCompression);
    frames.push_back(img);
}

Magick::writeImages(frames.begin(), frames.end(), outPath);

i have 16 images (each 640x640), the resulting gif is 4.5 mb. i also created a gif from the command line with `convert *.jpg -delay 1 result.gif`. file size is still 4.5 mb but quality is better. the following are my questions:

* what are the defaults for creating gif from the command line so i can apply them to my c++ code?
* how can i reduce file size but maintain quality?
* is setting -colors to 128 enough to make the gif in 128 colors?
* how can i reduce the noise in created gifs?

thanks in advance.

hi all

just wanted to bump this.

See
https://www.imagemagick.org/Usage/anim_opt/
https://www.imagemagick.org/Usage/anim_basics/

To reduce file size use -layers optimize. Also use the same color table for all frames via -remap. See https://www.imagemagick.org/Usage/quantize/#remap

+dither -colors 128 will ensure you have no more than 128 colors, but it could be less.

You will have to explain further about noise. But I suspect the use of -remap will help. That way, you do not get different sets of the same number of colors for each frame.

Legacy ImageMagick Discussions Archive

defaults for gif creation

defaults for gif creation

Re: defaults for gif creation

Re: defaults for gif creation