Configuration Constants

All settings can be configured via the Talking Head > Settings admin page. You can also override any setting using PHP constants in wp-config.php or environment variables of the same name.

Priority: constant > environment variable > database (admin UI) > default

When a setting is locked by a constant or environment variable, the admin field is disabled and shows “Locked by constant or environment variable.”

Note: As of v1.5.0, this plugin requires WordPress 7.0+ and uses the built-in WordPress AI Client for text-to-speech. Configure AI connectors at Settings → Connectors — no API keys needed in plugin settings.

Voice

// Default voice for new speaker profiles: 'alloy', 'echo', 'fable', 'onyx', 'nova', or 'shimmer'
define( 'TALKING_HEAD_DEFAULT_VOICE', 'alloy' );

Audio Processing

// Stitching mode: 'file' (concatenate on server) or 'virtual' (serve segments individually)
define( 'TALKING_HEAD_STITCHING_MODE', 'file' );

// Absolute path to the FFmpeg binary (optional — PHP fallback if not found)
define( 'TALKING_HEAD_FFMPEG_PATH', '/usr/bin/ffmpeg' );

// Output format: 'mp3' or 'aac'
define( 'TALKING_HEAD_OUTPUT_FORMAT', 'mp3' );

// Output bitrate: '128k', '192k', '256k', or '320k'
define( 'TALKING_HEAD_OUTPUT_BITRATE', '192k' );

// Milliseconds of silence between turns (0–5000)
define( 'TALKING_HEAD_SILENCE_GAP_MS', '500' );

Limits

// Maximum turns per episode (1–200)
define( 'TALKING_HEAD_MAX_SEGMENTS', '50' );

// Maximum characters per turn (100–4096)
define( 'TALKING_HEAD_MAX_SEGMENT_CHARS', '4096' );

// API requests per minute (1–60)
define( 'TALKING_HEAD_RATE_LIMIT', '10' );

Reference Table

Constant	Default	Allowed Values
TALKING_HEAD_DEFAULT_VOICE	alloy	alloy, echo, fable, onyx, nova, shimmer
TALKING_HEAD_STITCHING_MODE	file	file, virtual
TALKING_HEAD_FFMPEG_PATH	/opt/homebrew/bin/ffmpeg	Any executable path
TALKING_HEAD_OUTPUT_FORMAT	mp3	mp3, aac
TALKING_HEAD_OUTPUT_BITRATE	192k	128k, 192k, 256k, 320k
TALKING_HEAD_SILENCE_GAP_MS	500	0–5000
TALKING_HEAD_MAX_SEGMENTS	50	1–200
TALKING_HEAD_MAX_SEGMENT_CHARS	4096	100–4096
TALKING_HEAD_RATE_LIMIT	10	1–60

📦 Source: soderlind/talking-head · Edit on GitHub