FFmpeg MCP Server

Instructions

Implementation Reference

• main.ts:31-79 (handler)

  The asynchronous handler function for the 'speed_up' tool. It processes input arguments, constructs the output file path if needed, executes ffmpeg to speed up the video using setpts, fps, and atempo filters, logs the output, and returns a success or error response.

  async (args) => {
    const output_file =
      args.output_file ||
      getOutputFilePath(args.input_file, path.extname(args.input_file))
  
    const result = x(ffmpeg, [
      `-i`,
      args.input_file,
      `-filter:v`,
      `setpts=${1 / args.speed_factor}*PTS,fps=fps=${args.max_fps}`,
      `-af`,
      `atempo=${args.speed_factor}`,
      `-y`,
      output_file,
    ])
  
    let output = ""
  
    for await (const line of result) {
      output += line
      await server.server.sendLoggingMessage({
        level: "debug",
        data: {
          line,
        },
      })
    }
  
    if (result.exitCode !== 0) {
      return {
        content: [
          {
            type: "text",
            text: `Error: ${output}`,
          },
        ],
        isError: true,
      }
    }
  
    return {
      content: [
        {
          type: "text",
          text: `Successfully sped up video to: ${output_file}`,
        },
      ],
    }
  },

• tools.ts:4-28 (schema)

  The schema definition for the 'speed_up' tool, including name, description, and Zod-validated input schema for input_file, output_file (optional), max_fps, and speed_factor.

  speed_up: {
    name: "speed_up",
    description: "Speed up a video",
    input: {
      input_file: z.string().describe("Path to input file"),
      output_file: z
        .string()
        .describe(
          "Path to output file, output to the same directory if not specified",
        )
        .optional(),
      max_fps: z
        .number()
        .min(1)
        .max(60)
        .default(30)
        .describe("Max FPS for the output file"),
      speed_factor: z
        .number()
        .min(0.1)
        .max(10)
        .default(2)
        .describe("Speed factor for the output file, default to 2x sped up"),
    },
  },

• main.ts:27-80 (registration)

  The registration of the 'speed_up' tool on the MCP server using server.tool(), passing the name, description, input schema from tools.ts, and the inline handler function.

  server.tool(
    tools.speed_up.name,
    tools.speed_up.description,
    tools.speed_up.input,
    async (args) => {
      const output_file =
        args.output_file ||
        getOutputFilePath(args.input_file, path.extname(args.input_file))
  
      const result = x(ffmpeg, [
        `-i`,
        args.input_file,
        `-filter:v`,
        `setpts=${1 / args.speed_factor}*PTS,fps=fps=${args.max_fps}`,
        `-af`,
        `atempo=${args.speed_factor}`,
        `-y`,
        output_file,
      ])
  
      let output = ""
  
      for await (const line of result) {
        output += line
        await server.server.sendLoggingMessage({
          level: "debug",
          data: {
            line,
          },
        })
      }
  
      if (result.exitCode !== 0) {
        return {
          content: [
            {
              type: "text",
              text: `Error: ${output}`,
            },
          ],
          isError: true,
        }
      }
  
      return {
        content: [
          {
            type: "text",
            text: `Successfully sped up video to: ${output_file}`,
          },
        ],
      }
    },
  )

• main.ts:9-13 (helper)

  Helper function used in the speed_up handler to generate a default output file path in the same directory as the input with '_output' suffix.

  const getOutputFilePath = (input: string, ext: string) => {
    const input_dir = path.dirname(input)
    const input_filename = path.basename(input, path.extname(input))
    return path.join(input_dir, `${input_filename}_output${ext}`)
  }