ffmpeg

Kind	ffi-c
Categories	multimedia video audio
Keywords	ffmpeg video audio media encoding decoding transcoding

FFmpeg bindings for Kit - video and audio processing

Files

File	Description
`kit.toml`	Package manifest with metadata and dependencies
`src/ffmpeg.kit`	Media info, transcoding, frame extraction, and thumbnails
`tests/ffmpeg.test.kit`	Tests for error types and API function existence
`examples/convert.kit`	Transcode video to different formats and resolutions
`examples/frames.kit`	Extract frames and analyze pixel brightness
`examples/info.kit`	Display media file metadata and properties
`examples/thumbnail.kit`	Generate thumbnails at various timestamps
`LICENSE`	MIT license file

Dependencies

No Kit package dependencies.

Installation

kit add gitlab.com/kit-lang/packages/kit-ffmpeg.git

Usage

import Kit.Ffmpeg

License

MIT License - see LICENSE for details.

Exported Functions & Types

`FFMPEGError`

FFMPEG error type with specific variants for different failure modes.

Variants

FFMPEGOpenError {message}

FFMPEGExtractError {message}

FFMPEGProcessError {message}

`close`

Close a media file and free associated resources.

Should be called when done working with a media file to release FFmpeg resources.

Parameters:

media - Record - Media handle returned from open

Returns: () - Unit value

{ptr: Ptr, ..} -> ()

`format`

Get the container format name.

Returns the name of the container format (e.g., "mp4", "matroska", "avi", "mov").

Parameters:

media - Record - Media handle returned from open

Returns: String - Format name

{ptr: Ptr, ..} -> String

`duration`

Get the total duration of the media file in seconds.

Parameters:

media - Record - Media handle returned from open

Returns: Float - Duration in seconds

{ptr: Ptr, ..} -> Float

`bitrate`

Get the overall bitrate in bits per second.

This is the combined bitrate of all streams (video + audio).

Parameters:

media - Record - Media handle returned from open

Returns: Int - Bitrate in bits per second

{ptr: Ptr, ..} -> Int

`width`

Get the width of the video stream in pixels.

Parameters:

media - Record - Media handle returned from open

Returns: Int - Width in pixels, or 0 if no video stream

{ptr: Ptr, ..} -> Int

`height`

Get the height of the video stream in pixels.

Parameters:

media - Record - Media handle returned from open

Returns: Int - Height in pixels, or 0 if no video stream

{ptr: Ptr, ..} -> Int

`fps`

Get the frame rate (frames per second) of the video stream.

Parameters:

media - Record - Media handle returned from open

Returns: Float - Frame rate in frames per second

{ptr: Ptr, ..} -> Float

`video-codec`

Get the name of the video codec.

Returns codec names like "h264", "vp9", "hevc", "av1", etc.

Parameters:

media - Record - Media handle returned from open

Returns: String - Video codec name

{ptr: Ptr, ..} -> String

`audio-codec`

Get the name of the audio codec.

Returns codec names like "aac", "mp3", "opus", "vorbis", etc.

Parameters:

media - Record - Media handle returned from open

Returns: String - Audio codec name

{ptr: Ptr, ..} -> String

`sample-rate`

Get the audio sample rate in Hz.

Common sample rates are 44100 Hz, 48000 Hz, 96000 Hz.

Parameters:

media - Record - Media handle returned from open

Returns: Int - Sample rate in Hz

{ptr: Ptr, ..} -> Int

`channels`

Get the number of audio channels.

Common values are 1 (mono), 2 (stereo), 6 (5.1 surround).

Parameters:

media - Record - Media handle returned from open

Returns: Int - Number of audio channels

{ptr: Ptr, ..} -> Int

`has-video?`

Check if the file contains a video stream.

Parameters:

media - Record - Media handle returned from open

Returns: Bool - True if file has a video stream, false otherwise

{ptr: Ptr, ..} -> Bool

`has-audio?`

Check if the file contains an audio stream.

Parameters:

media - Record - Media handle returned from open

Returns: Bool - True if file has an audio stream, false otherwise

{ptr: Ptr, ..} -> Bool

`info`

Get all media information as a record.

Convenience function that gathers all metadata into a single record.

Parameters:

media - Record - Media handle returned from open

Returns: Record - Record containing all media metadata with fields:format, duration, bitrate, width, height, fps,video-codec, audio-codec, sample-rate, channels,has-video, has-audio

{ptr: Ptr, ..} -> {format: String, duration: Float, bitrate: Int, width: Int, height: Int, fps: Float, video-codec: String, audio-codec: String, sample-rate: Int, channels: Int, has-video: Bool, has-audio: Bool}

result = open "video.mp4"
match result
  | Ok media ->
    info-rec = info media
    print "Resolution: ${Int.to-string info-rec.width}x${Int.to-string info-rec.height}"
  | Err msg -> print msg

`print-info`

Print formatted media information to stdout.

Displays format, duration, bitrate, video specs (if present), and audio specs (if present).

Parameters:

media - Record - Media handle returned from open

Returns: () - Unit value

{ptr: Ptr, ..} -> ()

result = open "video.mp4"
match result
  | Ok media ->
    print-info media
    close media
  | Err msg -> print msg

`extract-frame`

{ptr: Ptr, ..} -> Float -> Result {ptr: Ptr, width: Int, height: Int} FFMPEGError

`free-frame`

{ptr: Ptr, ..} -> ()

`frame-width`

{width: Int, ..} -> Int

`frame-height`

{height: Int, ..} -> Int

`pixel-r`

{ptr: Ptr, ..} -> Int -> Int -> Int

`pixel-g`

{ptr: Ptr, ..} -> Int -> Int -> Int

`pixel-b`

{ptr: Ptr, ..} -> Int -> Int -> Int

`get-pixel`

{ptr: Ptr, ..} -> Int -> Int -> {r: Int, g: Int, b: Int}

`save-thumbnail`

{ptr: Ptr, ..} -> Float -> Int -> Int -> String -> Result () FFMPEGError

`generate-thumbnail`

{ptr: Ptr, ..} -> Int -> Int -> String -> Result () FFMPEGError

`extract-audio`

{ptr: Ptr, ..} -> Float -> Float -> Result {ptr: Ptr, num-samples: Int} FFMPEGError

`free-audio`

{ptr: Ptr, ..} -> ()

`audio-num-samples`

{num-samples: Int, ..} -> Int

`audio-get-sample`

{ptr: Ptr, ..} -> Int -> Float

`create-transcoder`

String -> String -> Int -> Int -> Int -> Result {ptr: Ptr} FFMPEGError

`transcode-process`

{ptr: Ptr, ..} -> Int

`transcode-finish`

{ptr: Ptr, ..} -> ()

`convert`

String -> String -> Int -> Int -> Int -> Result () FFMPEGError

`convert-simple`

String -> String -> Result () FFMPEGError

`convert-resize`

String -> String -> Int -> Int -> Result () FFMPEGError

`guess-format`

String -> String

`can-encode?`

String -> Bool

`can-decode?`

String -> Bool

`resolution-string`

{ptr: Ptr, ..} -> String

`duration-string`

{ptr: Ptr, ..} -> String

`duration-string-long`

{ptr: Ptr, ..} -> String

`bitrate-string`

{ptr: Ptr, ..} -> String

`is-video?`

{ptr: Ptr, ..} -> Bool

`is-audio-only?`

{ptr: Ptr, ..} -> Bool