pagecast

Instructions

Implementation Reference

• src/converter.js:70-93 (handler)

  Handler implementation for converting WebM to MP4 using ffmpeg.

  export async function convertToMp4(webmPath, options = {}) {
    await checkFfmpeg();
    await access(webmPath);
  
    const mp4Path = options.outputPath || webmPath.replace(/\.webm$/, '.mp4');
    const crf = options.crf || 23; // quality: lower = better, 18-28 is reasonable
  
    await run('ffmpeg', [
      '-i', webmPath,
      '-c:v', 'libx264',
      '-preset', 'slow',
      '-crf', String(crf),
      '-pix_fmt', 'yuv420p',
      '-movflags', '+faststart',
      '-y', mp4Path
    ]);
  
    const mp4Stat = await stat(mp4Path);
    return {
      mp4Path,
      sizeBytes: mp4Stat.size,
      sizeMB: (mp4Stat.size / 1024 / 1024).toFixed(2)
    };
  }

• src/index.js:123-144 (registration)

  MCP tool registration for convert_to_mp4.

  // Tool 5: Convert WebM to MP4
  mcp.tool(
    'convert_to_mp4',
    'Convert a .webm video to MP4 (H.264). Widely compatible for social media, sharing, and embedding.',
    {
      webmPath: z.string().describe('Path to the .webm file'),
      crf: z.number().optional().default(23).describe('Quality (18=high, 23=default, 28=small file)')
    },
    async ({ webmPath, crf }) => {
      try {
        const result = await convertToMp4(webmPath, { crf });
        return {
          content: [{
            type: 'text',
            text: `MP4 created!\n\nFile: ${result.mp4Path}\nSize: ${result.sizeMB} MB`
          }]
        };
      } catch (err) {
        return { content: [{ type: 'text', text: `Error: ${err.message}` }], isError: true };
      }
    }
  );