Media Playback

Status: Current Last updated: 2026-03-30 13:40 EDT

Play audio or video files linked via @Media: headers directly inside VS Code. The extension sources timing segments from the language server’s alignment sidecar when available, falling back to direct bullet parsing (bulletParser.ts) when the LSP is unavailable.

Play at Cursor

Shortcut: Cmd+Shift+Enter (macOS) / Ctrl+Shift+Enter (Windows/Linux)

Plays the single bullet segment nearest to the cursor position. A media panel opens in the editor showing playback controls. The segment is determined by the timing bullet on or nearest to the current editor line — for example, if the cursor is on a *CHI: line containing go home ., playback covers the time range in that line’s bullet.

(SCREENSHOT: Media panel with speed slider and playback controls) Capture this: open a .cha file with media, press Cmd+Shift+Enter, and screenshot the media panel showing the speed slider, play/pause button, and time display.

Continuous Play

Shortcut: Cmd+Shift+/ (macOS) / Ctrl+Shift+/ (Windows/Linux)

Plays all segments from the cursor position through to the end of the file. The editor selection tracks the currently-playing utterance line, scrolling the document to keep the active line visible.

Segments play sequentially in document order (top to bottom), not sorted by media time. When one segment finishes, playback seeks to the next segment’s start time.

[VIDEO: 30s demo of continuous playback) Capture this: start continuous playback from the middle of a multi-speaker file. Show the editor cursor advancing through utterance lines as each segment plays.

Playback Speed

The media panel toolbar includes a speed slider ranging from 0.25x to 2x. Drag the slider to adjust playback speed — the current rate is shown next to the slider. This is particularly useful for slowing down fast speech during transcription or alignment review.

Rewind

Shortcut: F8

Rewinds playback by a configurable number of seconds (default: 2). The rewind amount is controlled by the talkbank.transcription.rewindSeconds setting:

{
  "talkbank.transcription.rewindSeconds": 3
}

The minimum value is 0.5 seconds. Rewind works during both single-segment and continuous playback.

Loop

Shortcut: F5

Toggles looping of the current segment. When enabled, the current bullet’s time range repeats automatically. The loop count is controlled by talkbank.walker.loopCount:

Value	Behavior
`1`	Play once (no looping)
`3`	Play three times, then advance
`0`	Loop indefinitely until manually stopped

Playback State Machine

The following diagram shows the states a playback session transitions through:

stateDiagram-v2
    [*] --> Idle
    Idle --> Loading : Cmd+Shift+Enter\nor Cmd+Shift+/
    Loading --> Playing : media loaded,\nsegment resolved
    Loading --> Error : media not found\nor decode failure
    Playing --> Paused : pause button
    Paused --> Playing : resume button
    Playing --> SegmentEnd : currentTime >= seg.end
    SegmentEnd --> Playing : loop count > 0\n(replay same segment)
    SegmentEnd --> Seeking : next segment exists\n(continuous mode)
    SegmentEnd --> Idle : no more segments\nor single-segment mode
    Seeking --> Playing : seek complete
    Playing --> Rewinding : F8
    Rewinding --> Playing : seek complete\n(currentTime - rewindSeconds)
    Error --> [*]
    Idle --> [*]

The playback loop in mediaPanel.js polls currentTime every 100 ms (matching CLAN’s polling interval). When currentTime >= seg.end / 1000, the loop either advances to the next segment (continuous mode), replays (loop mode), or stops (single-segment mode).

Overlapping Bullets (Cross-Speaker Overlap)

CHAT allows cross-speaker overlapping bullets — two different speakers can have utterances whose time ranges overlap, as long as utterances are ordered by start time in the file (validation rule E701). Same-speaker self-overlap beyond 500 ms is prohibited by E704.

When the file contains overlapping bullets, playback works as follows:

Play at Cursor plays exactly the clicked utterance’s time range. No other utterances are affected.
Continuous Play plays each utterance in full, in document order. If speaker A’s utterance covers 0–3.5s and speaker B’s covers 2–2.5s, you hear A’s full range, then B’s full range. The overlapping audio region (2–2.5s) is heard twice — once as part of each speaker’s turn. This matches CLAN behavior and lets you hear each speaker’s complete utterance without truncation.
Waveform overlays render each segment independently. Overlapping segments appear as stacked colored bars on the waveform (see Waveform Visualization).

This behavior is intentional. For transcripts with frequent backchannels and short overlapping speech (common in aphasia protocols, conversation analysis, and multi-party recordings), hearing each speaker’s complete turn in sequence is more useful than trying to play simultaneous audio streams.

Requirements

The .cha file must contain an @Media: header specifying the filename and type (audio or video). For example: @Media: interview, audio
The referenced media file must be findable by the extension’s media resolver — see Media Resolution for the full search order.
The media format must be playable by the browser engine embedded in VS Code (typically MP3, WAV, MP4, WebM).

Stop Playback

Use the Command Palette (Cmd+Shift+P) and search for TalkBank: Stop Playback to halt any active playback session.

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