libx265 no use

When converting an image sequence to video using H265, the process gets blocked and fails to generate the video. This issue does not occur with H264 (i.e., H264 works properly).

`let filter_string = `[0:v]format=pix_fmts=rgba,split[alpha][normal];[alpha]alphaextract,pad=${this.imageWidth * 2}[alpha2];[alpha2][normal]overlay=x=${this.imageWidth}`;

await this.ffmpeg?.exec([
'-r', fps.toString(),
'-i', 'out/frame_%03d.png',
'-hide_banner',
'-c:v', 'libx265',
'-tag:v','hvc1',
'-b:v', `${bitrate}k`,
'-filter_complex', filter_string,
'-y', 'out/output.mp4'
]);`