lai alignment

The lai alignment command aligns audio/video files with captions.

Commands

Command	Description
`lai alignment align`	Align local audio/video with caption
`lai alignment youtube`	Download & align YouTube content

lai alignment align

Align a local audio or video file with an existing caption file.

lai alignment align <audio> <caption> <output>

Arguments

Argument	Description
`audio`	Path to audio or video file
`caption`	Path to input caption file (SRT, VTT, etc.)
`output`	Path for aligned output file

Options

Option	Description	Default
`alignment.device`	Processing device (`cpu`, `cuda`, `mps`)	`cpu`
`caption.split_sentence`	Enable smart sentence splitting	`false`
`caption.word_level`	Enable word-level timestamps	`false`
`media.channel_selector`	Audio channel (`left`, `right`, `average`)	`average`
`media.streaming_chunk_secs`	Chunk size for streaming (1-1800 seconds)	`600`

Examples

Basic alignment:

lai alignment align audio.wav caption.srt output.srt

With GPU acceleration:

lai alignment align video.mp4 caption.vtt output.srt alignment.device=cuda

With sentence splitting and word-level timestamps:

lai alignment align audio.wav caption.srt output.json \
    caption.split_sentence=true \
    caption.word_level=true

Long audio with streaming:

lai alignment align long_audio.wav subtitle.srt output.srt \
    media.streaming_chunk_secs=300.0

lai alignment youtube

Download a YouTube video and align it with auto-downloaded subtitles.

lai alignment youtube <url>

Arguments

Argument	Description
`url`	YouTube video URL

Options

Option	Description	Default
`media.output_dir`	Directory for downloaded files	Current directory
`caption.output_path`	Path for aligned output	`aligned.srt`
`caption.split_sentence`	Enable smart sentence splitting	`false`
`media.streaming_chunk_secs`	Chunk size for streaming	`600`

Examples

Basic YouTube alignment:

lai alignment youtube "https://youtube.com/watch?v=VIDEO_ID"

With custom output directory:

lai alignment youtube "https://youtube.com/watch?v=VIDEO_ID" \
    media.output_dir=~/Downloads \
    caption.output_path=aligned.srt \
    caption.split_sentence=true

Output Formats

The output format is determined by the file extension:

Extension	Format
`.srt`	SubRip
`.vtt`	WebVTT
`.ass`	Advanced SubStation Alpha
`.json`	JSON (preserves word-level data)
`.txt`	Plain text
`.ttml`	TTML (broadcast)
`.xml`	FCPXML, Premiere XML, Avid DS

lai alignment

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