压缩 GIF

复制from PIL import Image
import os

# 压缩 GIF：减帧 + 减色
input_path = "input.gif"
output_path = "output.gif"

with Image.open(input_path) as im:
    frames = []
    # 每隔一帧取一帧，减少帧数
    for i in range(0, im.n_frames, 2):
        im.seek(i)
        # 复制帧并转换为调色板模式，减少颜色数
        frame = im.copy().convert("P", palette=Image.ADAPTIVE, colors=64)
        frames.append(frame)
    
    # 保存为 GIF，优化调色板
    frames[0].save(
        output_path,
        save_all=True,
        append_images=frames[1:],
        optimize=True,
        duration=im.info.get("duration", 100),
        loop=0
    )

print(f"压缩完成：{os.path.getsize(input_path)} -> {os.path.getsize(output_path)} bytes")

复制package main

import (
	"fmt"
	"image"
	"image/color/palette"
	"image/gif"
	"os"
)

func main() {
	inputFile, _ := os.Open("input.gif")
	defer inputFile.Close()

	inGif, _ := gif.DecodeAll(inputFile)

	// 减帧：只保留偶数帧
	outGif := &gif.GIF{}
	for i := 0; i < len(inGif.Image); i += 2 {
		// 减色：量化为 64 色调色板
		pal := palette.Plan9[:64]
		quantized := image.NewPaletted(inGif.Image[i].Bounds(), pal)
		for y := 0; y < inGif.Image[i].Bounds().Dy(); y++ {
			for x := 0; x < inGif.Image[i].Bounds().Dx(); x++ {
				quantized.Set(x, y, inGif.Image[i].At(x, y))
			}
		}
		outGif.Image = append(outGif.Image, quantized)
		outGif.Delay = append(outGif.Delay, inGif.Delay[i])
	}

	outFile, _ := os.Create("output.gif")
	defer outFile.Close()
	gif.EncodeAll(outFile, outGif)

	fmt.Println("GIF 压缩完成")
}

复制const sharp = require('sharp');
const fs = require('fs');

// 注意：sharp 不直接支持 GIF 减帧，这里演示调用外部 FFmpeg 的 Node 方式
const { execSync } = require('child_process');

// 减帧：每 2 帧取 1 帧；减色：使用 64 色调色板
const input = 'input.gif';
const output = 'output.gif';

// 使用 FFmpeg 进行压缩
execSync(`ffmpeg -i ${input} -vf "select='not(mod(n,2))',setpts=0.5*PTS,palettegen=max_colors=64:stats_mode=diff" -vsync 0 palette.png`);
execSync(`ffmpeg -i ${input} -i palette.png -lavfi "select='not(mod(n,2))',setpts=0.5*PTS,paletteuse=dither=bayer:bayer_scale=5" -y ${output}`);

const inputSize = fs.statSync(input).size;
const outputSize = fs.statSync(output).size;
console.log(`压缩完成：${inputSize} -> ${outputSize} bytes`);

// 清理临时文件
fs.unlinkSync('palette.png');