RenderIO automatically extracts rich metadata from every processed file using ffprobe, including duration, resolution, codec, bitrate, and more.

File Metadata

Every file that RenderIO processes is automatically analyzed with ffprobe to extract detailed media metadata. This happens for command output files, stored files, and uploaded files -- no extra API calls needed.

Available metadata fields

The following fields are extracted and returned with every file:

Field	Type	Description	Example
`duration`	number	Duration in seconds	`30.5`
`file_type`	string	General type of the media	`"video"`, `"audio"`, `"image"`
`file_format`	string	Container format	`"mp4"`, `"webm"`, `"png"`
`codec`	string	Primary codec used	`"h264"`, `"aac"`, `"vp9"`
`pixel_format`	string	Pixel format (video/image only)	`"yuv420p"`, `"rgb24"`
`mime_type`	string	MIME type of the file	`"video/mp4"`, `"audio/mpeg"`
`width`	number	Width in pixels (video/image only)	`1920`
`height`	number	Height in pixels (video/image only)	`1080`
`frame_rate`	number	Frames per second (video only)	`29.97`
`bitrate_video_kb`	number	Video bitrate in kilobits/sec	`2500`
`bitrate_audio_kb`	number	Audio bitrate in kilobits/sec	`128`
`sample_rate`	number	Audio sample rate in Hz	`44100`
`channels`	number	Number of audio channels	`2`
`size_mbytes`	number	File size in megabytes	`12.4`

Fields that do not apply to a particular file type are returned as null. For example, an audio-only file will have null for width, height, frame_rate, and pixel_format.

Where metadata appears

In command poll responses

When you poll a completed command, each entry in the output_files map includes its metadata:

curl https://renderio.dev/api/v1/commands/550e8400-e29b-41d4-a716-446655440000 \
  -H "X-API-KEY: ffsk_your_api_key"

{
  "command_id": "550e8400-e29b-41d4-a716-446655440000",
  "status": "SUCCESS",
  "output_files": {
    "out_video": {
      "file_id": "a1b2c3d4-...",
      "storage_url": "https://storage.renderio.dev/...",
      "status": "STORED",
      "filename": "output.mp4",
      "size_mbytes": 12.4,
      "duration": 30.5,
      "file_type": "video",
      "file_format": "mp4",
      "codec": "h264",
      "pixel_format": "yuv420p",
      "mime_type": "video/mp4",
      "width": 1920,
      "height": 1080,
      "frame_rate": 29.97,
      "bitrate_video_kb": 2500,
      "bitrate_audio_kb": 128
    }
  }
}

In file detail responses

You can also retrieve metadata for any individual file using its file_id:

curl https://renderio.dev/api/v1/files/a1b2c3d4-... \
  -H "X-API-KEY: ffsk_your_api_key"

{
  "file_id": "a1b2c3d4-...",
  "storage_url": "https://storage.renderio.dev/...",
  "status": "STORED",
  "rendi_store_type": "OUTPUT",
  "is_deleted": false,
  "size_mbytes": 12.4,
  "duration": 30.5,
  "file_type": "video",
  "file_format": "mp4",
  "codec": "h264",
  "pixel_format": "yuv420p",
  "mime_type": "video/mp4",
  "width": 1920,
  "height": 1080,
  "frame_rate": 29.97,
  "bitrate_video_kb": 2500,
  "bitrate_audio_kb": 128,
  "sample_rate": 44100,
  "channels": 2,
  "created_at": "2025-01-15T10:30:00Z"
}

Stored files and uploads

Metadata extraction is not limited to command outputs. Files stored via POST /api/v1/files/store-file and files uploaded via POST /api/v1/files/upload also get full metadata extraction automatically.

# Store a remote file - metadata is extracted automatically
curl -X POST https://renderio.dev/api/v1/files/store-file \
  -H "X-API-KEY: ffsk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ "file_url": "https://example.com/my-video.mp4" }'

Use cases for metadata

Metadata makes it easy to validate your FFmpeg output without downloading the file:

Verify dimensions after resize: Check that width and height match your target resolution
Confirm codec after transcode: Ensure codec is "h264" after converting from another format
Check file size: Use size_mbytes to confirm compression was effective
Validate duration: Make sure duration matches the expected length after trimming or concatenation
Audio properties: Verify sample_rate and channels for audio processing workflows

Audio-specific fields

For audio files or media with audio tracks, these fields provide audio stream details:

Field	Description
`sample_rate`	Sample rate in Hz (e.g., `44100`, `48000`)
`channels`	Number of channels (`1` = mono, `2` = stereo, `6` = 5.1 surround)
`bitrate_audio_kb`	Audio bitrate in kilobits per second
`codec`	Audio codec when the file is audio-only (e.g., `"aac"`, `"mp3"`, `"opus"`)

Get File endpoint -- retrieve metadata for any stored file by ID
File Aliases -- how input and output files map to your commands

File Metadata

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