webm_creator.py

import av
import numpy as np
from PIL import Image
import os

def png_to_webm_with_alpha(input_folder, output_file, fps=12):
    # 获取所有PNG文件并按名称排序
    png_files = sorted([f for f in os.listdir(input_folder) if f.endswith('.png')])
    if not png_files:
        raise ValueError("No PNG files found in the input folder")

    first_image = Image.open(os.path.join(input_folder, png_files[0]))
    width, height = first_image.size

    # 创建输出容器和视频流
    container = av.open(output_file, mode='w')
    stream = container.add_stream('libvpx-vp9', rate=fps)
    stream.pix_fmt = 'yuva420p'
    stream.width = width
    stream.height = height

    # 设置编码器参数
    stream.options = {
        'quality': 'good',
        'crf': '35',
        'auto-alt-ref': '0',
    }

    for png_file in png_files:
        image_path = os.path.join(input_folder, png_file)
        image = Image.open(image_path).convert('RGBA')
        frame_data = np.array(image)

        # 创建AVFrame并填充数据
        frame = av.VideoFrame.from_ndarray(frame_data, format='rgba')

        # 编码并写入
        for packet in stream.encode(frame):
            container.mux(packet)

    # 刷新编码器（修复此处：传入 None 表示结束）
    for packet in stream.encode(None):  # <-- 更安全的刷新方式
        container.mux(packet)

    container.close()

if __name__ == "__main__":
    input_folder = "pngs"
    output_file = "output.webm"
    png_to_webm_with_alpha(input_folder, output_file, fps=12)