ffmpeg-mcp-server

by Ashutos1997

Overview Schema Source Related Servers Discussions Admin

TypeScript

Local

change_speed

Adjust video or audio playback speed to create fast-forward, slow-motion, or timelapse output while correcting pitch.

Instructions

Change video and audio playback speed (such as 2x for fast forward or 0.5x for slow motion) with pitch correction.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "inputPath": "<inputPath>",
      "outputPath": "<outputPath>",
      "speed": "<speed>"
    },
    "name": "change_speed"
  }
}

Input Schema

Name	Required	Description
`speed`	Yes	Playback speed multiplier (e.g., 2.0 for 2x fast-forward/timelapse, 0.5 for slow-motion)
`inputPath`	Yes	Path to the source video or audio file
`muteAudio`	No	Whether to strip audio track completely
`outputPath`	Yes	Target output file path

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 21, 2026

TDQS

B3.3/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden of behavioral disclosure. It usefully states that pitch correction is applied, which is a meaningful behavioral trait beyond a simple speed change. However, it omits important mutation details such as whether an existing output file is overwritten, what formats are supported, and how the muteAudio option interacts with pitch correction.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence with zero waste. It names the action, media types, example values, and a key behavioral note (pitch correction) without unnecessary elaboration.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a file-transforming tool with no annotations and no output schema, the description is minimally adequate but leaves out important context: overwrite behavior, supported input/output formats, and how muteAudio affects the result. The rich schema covers parameters, but the behavioral completeness is still thin.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so all four parameters are already documented in the schema, including speed examples and the muteAudio flag. The description repeats the speed examples and adds 'pitch correction,' but does not add meaningful semantics for inputPath, outputPath, or muteAudio beyond what the schema provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: changing video and audio playback speed, with examples like 2x fast forward and 0.5x slow motion. It is clearly distinct from sibling media tools, but it does not explicitly contrast itself with alternatives such as trim_media or media_convert.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no guidance on when to use this tool versus alternatives. Sibling tools like media_convert, trim_media, and compress_video are not mentioned, so the agent must infer the use case from the tool name and description alone.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.