MCP FFmpeg Helper

Instructions

Implementation Reference

• src/tools/handlers.ts:80-105 (handler)

  Main execution logic for trim_video tool: validates input/output paths, handles startTime, duration or endTime, builds FFmpeg command with stream copy (-c copy) for efficient trimming without re-encoding, executes via runFFmpegCommand, and returns completion message.

  case "trim_video": {
    const inputPath = validatePath(String(args?.inputPath), true);
    const outputPath = validatePath(String(args?.outputPath));
    const startTime = String(args?.startTime || "0");
    const duration = String(args?.duration || "");
    const endTime = String(args?.endTime || "");
    
    await ensureDirectoryExists(outputPath);
    
    let command = `-i "${inputPath}" -ss ${startTime}`;
    if (duration) {
      command += ` -t ${duration}`;
    } else if (endTime) {
      command += ` -to ${endTime}`;
    }
    command += ` -c copy "${outputPath}" -y`;
    
    const result = await runFFmpegCommand(command);
    
    return {
      content: [{
        type: "text",
        text: `Video trimming completed: ${inputPath} → ${outputPath}\n\n${result}`
      }]
    };
  }

• src/tools/definitions.ts:98-127 (schema)

  Tool schema definition: name, description, and inputSchema specifying properties for inputPath (required), outputPath (required), and optional startTime, duration, endTime as strings.

  {
    name: "trim_video",
    description: "Trim a video to a specific duration",
    inputSchema: {
      type: "object",
      properties: {
        inputPath: {
          type: "string",
          description: "Path to the input video file"
        },
        outputPath: {
          type: "string",
          description: "Path for the output video file"
        },
        startTime: {
          type: "string",
          description: "Start time (format: HH:MM:SS.mmm or seconds)"
        },
        duration: {
          type: "string",
          description: "Duration (format: HH:MM:SS.mmm or seconds)"
        },
        endTime: {
          type: "string",
          description: "End time (format: HH:MM:SS.mmm or seconds)"
        }
      },
      required: ["inputPath", "outputPath"]
    }
  },

• src/index.ts:46-50 (registration)

  Registers trim_video tool schema by including it in the toolDefinitions array returned for ListToolsRequest.

  server.setRequestHandler(ListToolsRequestSchema, async () => {
    return {
      tools: toolDefinitions
    };
  });

• src/index.ts:56-68 (registration)

  Registers the general tool call handler that dispatches 'trim_video' calls to the specific handleToolCall implementation in handlers.ts.

  server.setRequestHandler(CallToolRequestSchema, async (request) => {
    try {
      return await handleToolCall(request.params.name, request.params.arguments);
    } catch (error: any) {
      console.error("Tool execution error:", error.message);
      return {
        content: [{
          type: "text",
          text: `Error: ${error.message}`
        }]
      };
    }
  });