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ffmpeg

package
v0.3.0 Latest Latest
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This package is not in the latest version of its module.

 Go to latest Published: Oct 5, 2026 License: AGPL-3.0 Imports: 16 Imported by: 0

Documentation

Overview

Package ffmpeg drives the ffmpeg and ffprobe processes that turn a source into a clip, a GIF, a still, or a preview.

Index

Constants

View Source 
const (

	// Height720p is the smallest height still called 720p.
	Height720p = 720
	// Height1080p is the smallest height still called 1080p.
	Height1080p = 1080
	// Height2160p is the smallest height called 4K.
	Height2160p = 2160
)

Variables

This section is empty.

Functions

func ChannelLayoutName 

func ChannelLayoutName(channels int) string

ChannelLayoutName names common speaker layouts.

Parameters:

  • channels: Audio channel count on the source.

Returns:

  • name: The layout's display name, or empty when the count is unknown.

func DefaultFFmpegTimeout 

func DefaultFFmpegTimeout() time.Duration

DefaultFFmpegTimeout returns the default FFmpeg timeout.

Returns:

  • timeout: The per-command deadline.

func DynamicRangeLabel 

func DynamicRangeLabel(transfer string) string

DynamicRangeLabel names a color transfer for display.

Parameters:

  • transfer: ffprobe color_transfer of the source.

Returns:

  • label: The transfer's display name, or empty when it is not HDR.

func IsHDRSource 

func IsHDRSource(transfer string) bool

IsHDRSource reports whether a source carries an HDR transfer.

Parameters:

  • transfer: ffprobe color_transfer of the source.

Returns:

  • hdr: True when the source is PQ or HLG.

func PreviewDuration 

func PreviewDuration(duration time.Duration) time.Duration

PreviewDuration caps a preview window so encodes stay cheap.

Parameters:

  • duration: Requested clip duration.

Returns:

  • capped: The window that will actually be encoded.

func SourceQuality 

func SourceQuality(info probe.Info) string

SourceQuality is a short label for what a source's video is.

Parameters:

  • info: Probed information for the source.

Returns:

  • label: The resolution and dynamic range, or empty when neither is known.

func SourceResolutionLabel 

func SourceResolutionLabel(height int) string

SourceResolutionLabel classifies a source height the way a viewer would name it.

Parameters:

  • height: Video height in pixels.

Returns:

  • label: The class name, or empty when the height is unknown.

Types

type ExecFFmpeg 

type ExecFFmpeg struct {
	// contains filtered or unexported fields
}

ExecFFmpeg runs the ffmpeg and ffprobe binaries.

func NewExecFFmpeg 

func NewExecFFmpeg(ffmpegPath, ffprobePath string) *ExecFFmpeg

NewExecFFmpeg creates a new FFmpeg executor.

Parameters:

  • ffmpegPath: Path to the ffmpeg binary.
  • ffprobePath: Path to the ffprobe binary.

Returns:

  • exec: An executor carrying the default timeout.

func (*ExecFFmpeg) DetectCrop 

func (execFFmpeg *ExecFFmpeg) DetectCrop(
	ctx context.Context,
	input string,
	start, duration time.Duration,
) (crop.CropRect, error)

DetectCrop samples the source with cropdetect and returns a crop rectangle.

Parameters:

  • ctx: Cancellation and deadline for the pass.
  • input: Source media path.
  • start: Seek offset into the source.
  • duration: Length of the clip.

Returns:

  • rect: The detected crop rectangle, or a zero value when there are no bars.
  • err: Non-nil only when the pass failed and produced no usable output.

func (*ExecFFmpeg) ExtractClip 

func (execFFmpeg *ExecFFmpeg) ExtractClip(
	ctx context.Context,
	input, output string,
	start, duration time.Duration,
	preset clip.QualityPreset,
	audioIndex int,
	rect crop.CropRect,
) error

ExtractClip encodes a clip segment with x264.

Parameters:

  • ctx: Cancellation and deadline for the encode.
  • input: Source media path.
  • output: Destination mp4 path.
  • start: Seek offset into the source.
  • duration: Length of the clip.
  • preset: Encode quality, including WebSafeColor.
  • audioIndex: Audio stream index on the source.
  • rect: Optional black-bar crop.

Returns:

  • err: Non-nil when the clip could not be encoded.

func (*ExecFFmpeg) ExtractGIF 

func (execFFmpeg *ExecFFmpeg) ExtractGIF(
	ctx context.Context,
	input, output string,
	start, duration time.Duration,
	width, fps int,
	rect crop.CropRect,
) error

ExtractGIF extracts a GIF from a video using the palettegen/paletteuse pair.

Parameters:

  • ctx: Cancellation and deadline for both passes.
  • input: Source media path.
  • output: Destination GIF path.
  • start: Seek offset into the source.
  • duration: Length of the GIF window.
  • width: Output width in pixels, or 0 for the default.
  • fps: Output frames per second, or 0 for the default.
  • rect: Optional black-bar crop.

Returns:

  • err: Non-nil when either pass failed.

func (*ExecFFmpeg) ExtractPreview 

func (execFFmpeg *ExecFFmpeg) ExtractPreview(
	ctx context.Context,
	input, output string,
	start, duration time.Duration,
	audioIndex int,
	rect crop.CropRect,
	preset clip.QualityPreset,
) error

ExtractPreview writes a short, downscaled, browser-safe preview segment.

Parameters:

  • ctx: Cancellation and deadline for the encode.
  • input: Source media path.
  • output: Destination mp4 path.
  • start: Seek offset into the source.
  • duration: Requested window, capped by PreviewDuration.
  • audioIndex: Audio stream index on the source.
  • rect: Optional black-bar crop.
  • preset: Encode options; only WebSafeColor is read.

Returns:

  • err: Non-nil when the preview could not be encoded.

func (*ExecFFmpeg) ExtractScreenshot 

func (execFFmpeg *ExecFFmpeg) ExtractScreenshot(
	ctx context.Context,
	input, output string,
	timestamp time.Duration,
	rect crop.CropRect,
) error

ExtractScreenshot extracts a screenshot from a video.

Parameters:

  • ctx: Cancellation and deadline for the encode.
  • input: Source media path.
  • output: Destination image path.
  • timestamp: Offset into the source to grab the frame from.
  • rect: Optional black-bar crop.

Returns:

  • err: Non-nil when the still could not be written.

func (*ExecFFmpeg) Probe 

func (execFFmpeg *ExecFFmpeg) Probe(ctx context.Context, path string) (probe.Info, error)

Probe probes a media file for information.

Parameters:

  • ctx: Cancellation and deadline for the probe.
  • path: Media file path.

Returns:

  • info: The probed media information.
  • err: Non-nil when the file cannot be probed.

Source Files

View all Source files

Directories

Path Synopsis
Package crop parses ffmpeg cropdetect rectangles.
 Package crop parses ffmpeg cropdetect rectangles.
Package probe reads what a source file actually is, using ffprobe.
 Package probe reads what a source file actually is, using ffprobe.
Package progress reports ffmpeg encode completion from stderr.
 Package progress reports ffmpeg encode completion from stderr.
Package tonemap builds the ffmpeg filter chain that maps an HDR source down to Rec.709 so a browser renders it the way it was graded.
 Package tonemap builds the ffmpeg filter chain that maps an HDR source down to Rec.709 so a browser renders it the way it was graded.

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