> ## Documentation Index > Fetch the complete documentation index at: https://docs.decktalk.ai/llms.txt > Use this file to discover all available pages before exploring further. # Configuration > Look up every DeckTalk tuning field, with its type, its default, and what it changes. Tuning fields change how DeckTalk records, assembles, and checks a video. This page lists every field, grouped by table, with its type, its default, and the values it accepts. A field whose Value column is empty takes any value of its type, and a value outside the stated range fails the load with the table and the field named. A tuning table can go in the project's `decktalk.toml`. The same field can also come from an environment variable. ```toml decktalk.toml theme={null} [video] preset = "veryfast" ``` ```console theme={null} DECKTALK_VIDEO_PRESET=veryfast decktalk build --no-voice ``` The scaffold builds with every default. Change `[video]` for faster drafts. Change `[verify]` when a small reveal fails the cue check. ## Which value wins Five layers can set a field. Each layer overrides the layers before it. 1. The default on this page. 2. The same table in the per-machine settings file. 3. The same table in the project's `decktalk.toml`. 4. An environment variable named `DECKTALK__`, such as `DECKTALK_VIDEO_PRESET`. 5. A command-line flag, for one run. The per-machine settings file is in a different place on each platform. | Linux | macOS | Windows | | ------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------ | ---------------------------------- | | `$XDG_CONFIG_HOME/decktalk/decktalk.toml`, or `~/.config/decktalk/decktalk.toml` when `XDG_CONFIG_HOME` is not set | `~/Library/Application Support/decktalk/decktalk.toml` | `%APPDATA%\decktalk\decktalk.toml` | Note: `DECKTALK_CONFIG` points at a different file. The per-machine file can hold only the tables on this page, and any other table fails the load. `decktalk doctor` prints the path in its `config` row. An environment variable for an array field takes comma-separated values, such as `DECKTALK_VERIFY_PROBE_DELAYS=0.7,1.5`. Four flags override a field for one run. | Flag | Commands | Overrides | | ---------- | ------------------- | --------------------------------------- | | `--preset` | `assemble`, `build` | `[video] preset` | | `--crf` | `assemble`, `build` | `[video] crf` | | `--settle` | `record` | `[record] settle_seconds` | | `--model` | `narrate` | `[narration] model` and `[voice] model` | Sections, the voice, mix levels, and soundscape prompts are project content, not tuning. [decktalk.toml](/reference/decktalk-toml) lists those tables. Secrets go only in `.env`. ## `[video]` These keys set the frame size and the encoding of every recording and of the final mp4. Environment variables start with `DECKTALK_VIDEO_`. | Field | Type | Default | Value | Meaning | | --------------- | --------- | ------------ | ------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------- | | `width` | `integer` | `1920` | must be above zero | Frame width in pixels, for every recording and the final mp4. | | `height` | `integer` | `1080` | must be above zero | Frame height in pixels, for every recording and the final mp4. | | `fps` | `integer` | `25` | must be above zero | Frames per second. Chromium records at 25 fps, so 25 avoids a pulldown that duplicates every sixth frame. | | `preset` | `string` | `"medium"` | must be one of ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow | x264 preset. Use veryfast for drafts. | | `crf` | `integer` | `18` | must be an x264 quality between 0 and 51 | x264 quality. A lower value gives higher quality and a larger file. | | `audio_bitrate` | `string` | `"192k"` | | AAC bitrate of the final mp4. | | `sample_rate` | `integer` | `48000` | must be above zero | Audio sample rate of the final mp4. Every audio input is resampled to it once. | | `channels` | `integer` | `2` | must be above zero | Audio channels of the final mp4. | | `slate_color` | `string` | `"0x0e1116"` | | Color of the plain frame that plays when a slate image cannot be rendered. | ## `[narration]` These keys govern how the script is turned into audio. Environment variables start with `DECKTALK_NARRATION_`. | Field | Type | Default | Value | Meaning | | ------------------------- | --------- | -------------------------- | -------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `model` | `string` | `"eleven_multilingual_v2"` | | Speech model. `[voice] model` and `narrate --model` override it. | | `output_format` | `string` | `"mp3_44100_128"` | | Audio format that the speech provider returns. It is part of the narration cache key. | | `mp3_bitrate` | `string` | `"128k"` | | Bitrate of the mp3 files that DeckTalk writes. They include click tracks and `narration.mp3`. | | `words_per_minute` | `integer` | `140` | must be above zero | Pacing of the estimated length in the `narrate` table. | | `silent_words_per_minute` | `integer` | `150` | must be above zero | Pacing of the click track in a build without voice. | | `lead_seconds` | `number` | `0.5` | must not be negative | Silence before the first word of every spoken section, so the picture changes before the voice speaks. A section's own `lead_seconds` replaces it. | | `silent_beat_seconds` | `number` | `0.7` | must not be negative | Seconds each beat adds to a section's length in a build without voice. | | `min_tail_seconds` | `number` | `0.7` | must not be negative | Silence after the last word of every spoken section, so a cut never falls on speech. The take is placed so that exactly this much follows its last sound. A section's own `tail_seconds` replaces it. | | `cache_dir` | `string` | `""` | | Directory that holds the take files and their words files, each named by its content hash. It is empty for `build/narration/` inside the project, and a path here keeps the voiced takes when `build/` is deleted and lets many projects share one cache. The take index and the joined narration stay under `build/narration/`, because they belong to one project. | | `context_chars` | `integer` | `1500` | must not be negative | Characters of each neighbor section sent with a request, for continuous prosody. | | `timeout_seconds` | `integer` | `180` | must be above zero | Seconds before a speech request times out. | ## `[record]` These keys tune the headless Chromium recording, how narration t=0 is found in it, and its sanity check. Environment variables start with `DECKTALK_RECORD_`. | Field | Type | Default | Value | Meaning | | ------------------------------ | --------- | --------- | ----------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------- | | `settle_seconds` | `number` | `0.5` | must not be negative | Shortest wait after the page is ready and before narration t=0. `record --settle` overrides it. | | `min_cover_seconds` | `number` | `1.5` | must not be negative | Shortest time from the start of the recorder to narration t=0. | | `browser_path` | `string` | `""` | | Chromium executable that `record` drives. It is empty for the build that `decktalk install` fetched, and a path here is what a managed machine sets. | | `color_scheme` | `string` | `"light"` | must be one of light, dark, no-preference | Color scheme that Chromium reports to the page. | | `retries` | `integer` | `2` | must not be negative | How many more times `record` records a section whose frames stalled. | | `screenshot_settle_ms` | `integer` | `400` | must not be negative | Milliseconds that `decktalk screenshots` waits before each slide screenshot. | | `cover_scan_seconds` | `number` | `4.0` | must not be negative | Seconds at the start of each recording that `record` scans for the magenta cover. | | `fallback_first_paint_seconds` | `number` | `1.1` | must not be negative | Guessed first paint if `record` finds no cover and no painted frame. `record` adds `settle_seconds` to it. | | `cover_luma_min` | `number` | `70` | must be a luma between 0 and 255 | A cover frame has an average luma above this. | | `cover_luma_max` | `number` | `140` | must be a luma between 0 and 255 | A cover frame has an average luma below this. | | `cover_chroma_min` | `number` | `165` | must be a luma between 0 and 255 | A cover frame has an average U and an average V above this. | | `painted_ymax` | `number` | `60` | must be a luma between 0 and 255 | A painted frame has a brightest luma above this. | | `painted_yavg_max` | `number` | `120` | must be a luma between 0 and 255 | A painted frame has an average luma below this, so a white flash does not count. | | `black_ymax` | `number` | `40` | must be a luma between 0 and 255 | `record` reports `BLACK?` when the brightest luma of the middle frame is below this. | | `truncated_slack_seconds` | `number` | `0.5` | must not be negative | Allowed shortfall of a recording against its requested length. A larger shortfall makes `record` report `TRUNCATED`. | | `stall_ms` | `integer` | `150` | must be above zero | Longest frame gap after narration t=0, in milliseconds. A longer gap makes `record` try again and report `STALLED`. | ## `[audio]` These keys set the mix mechanics. Levels live in `[mix]` in `decktalk.toml`. Environment variables start with `DECKTALK_AUDIO_`. | Field | Type | Default | Value | Meaning | | --------------------------- | -------- | ------- | -------------------- | -------------------------------------------------------------------- | | `duck_ramp_seconds` | `number` | `0.5` | must not be negative | Ramp of the music duck at each edge of a spoken span or a clip. | | `ambience_ramp_seconds` | `number` | `1.0` | must not be negative | Ramp of the ambience bed at each edge of its span. | | `ambience_pad_seconds` | `number` | `0.5` | must not be negative | Seconds that the ambience bed extends past each edge of its section. | | `marker_mute_ramp_seconds` | `number` | `0.04` | must not be negative | Ramp into and out of a marker's mute. | | `marker_boost_ramp_seconds` | `number` | `0.3` | must not be negative | Ramp into and out of a marker's swell. | ## `[verify]` These keys tune the checks on the assembled mp4. Environment variables start with `DECKTALK_VERIFY_`. | Field | Type | Default | Value | Meaning | | ------------------------ | ------------------ | ------------ | -------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `after_dip_seconds` | `number` | `0.2` | must not be negative | Seconds after a section start to the frame that the start check reads. | | `reference_lead_seconds` | `number` | `0.1` | must not be negative | Reference lead. It has an effect only above (`max_offset_frames` + 1.5) / `fps`, which is 0.14 s at the defaults. | | `probe_delays` | `array of numbers` | `[0.7, 1.5]` | must be one or more delays above zero | Seconds after the cue time for each probe. The later probe catches a slow reveal. | | `diff_level` | `integer` | `40` | must be a luma between 0 and 255 | Luma difference that a pixel must exceed to count as changed, for probes and control shares. | | `min_changed_percent` | `number` | `0.1` | must be a percentage between 0 and 100 | Smallest changed share, in percent, that the reported probe needs. | | `min_margin_percent` | `number` | `0.1` | must be a percentage between 0 and 100 | Smallest margin, in percentage points, that the reported probe needs. | | `thin_change_factor` | `number` | `3.0` | must be above zero | A passing cue whose changed share or margin is below this many times its floor reads `THIN CHANGE?`, an uncertain finding. 1 turns the warning off. | | `onset_percent` | `number` | `0.01` | must be a percentage between 0 and 100 | Rise in changed share from one frame to the next that marks the onset. It is in percentage points. 0.01 is about 13 pixels. | | `onset_diff_level` | `integer` | `12` | must be a luma between 0 and 255 | Luma difference that a pixel must exceed to count as changed, for the onset scan only. | | `click_search_seconds` | `number` | `0.25` | must not be negative | Seconds on each side of the cued word's start that the click search covers. | | `max_offset_frames` | `integer` | `2` | must not be negative | Offset limit, in frames. The onset can sit this far from the cue time, early or late. | | `max_av_frames` | `integer` | `3` | must not be negative | a/v limit, in frames, early or late. It is wider because the click carries encoding jitter too. | | `visible_ymax` | `number` | `60` | must be a luma between 0 and 255 | The start check reports `BLACK` when the brightest luma of its frame is at most this. | | `cut_window_seconds` | `number` | `0.15` | must not be negative | Seconds of narration before each cut that the cut check measures. | | `cut_max_db` | `number` | `-40.0` | | Loudest RMS level of the cut window, in dBFS, that passes the cut check. | | `max_pop_percent` | `number` | `0.1` | must be a percentage between 0 and 100 | Largest changed share, in percent, across the cut into a section that sets `seamless`. A larger share reads `POP AT CUT`. | | `probe_width` | `integer` | `480` | must be above zero | Width in pixels that frames are scaled to before a comparison. | | `probe_height` | `integer` | `270` | must be above zero | Height in pixels that frames are scaled to before a comparison. | | `block_width` | `integer` | `240` | must be above zero | Width in pixels of the block-averaged copy of each frame that confirms an onset. Each pixel then averages an 8 by 8 block of a 1080p frame, the size of an H.264 transform block. The encoder can shift a few pixels of a still picture by up to about 15 levels in the frames just before a change. The average cancels that ringing, so a frame is the onset only when a block also changed. | | `block_height` | `integer` | `135` | must be above zero | Height in pixels of the block-averaged copy of each frame that confirms an onset. | ## `[elevenlabs]` These keys point at the ElevenLabs API and size its soundscape requests. Environment variables start with `DECKTALK_ELEVENLABS_`. | Field | Type | Default | Value | Meaning | | --------------------------- | --------- | -------------------------------- | ----------------------- | ------------------------------------------------------------------------------------------ | | `api_base` | `string` | `"https://api.elevenlabs.io/v1"` | | Base URL of the ElevenLabs API. | | `sound_model` | `string` | `"eleven_text_to_sound_v2"` | | Model for ambience and sound effect requests. A soundscape table can name its own. | | `music_model` | `string` | `"music_v2"` | | Model for music requests. A soundscape table can name its own. | | `music_bitrate` | `string` | `"192k"` | | Bitrate of the music file that `soundscape` joins from its chunks. | | `max_music_chunk_seconds` | `integer` | `300` | must be above zero | Longest music request. Longer music is requested in chunks. | | `music_crossfade_seconds` | `integer` | `2` | must not be negative | Crossfade between two music chunks. | | `ambience_seconds` | `number` | `25.0` | must be above zero | Length of a generated ambience bed. A soundscape table can set `duration_seconds` instead. | | `ambience_prompt_influence` | `number` | `0.3` | must be between 0 and 1 | Prompt influence of an ambience request. A soundscape table can set its own. | | `sfx_seconds` | `number` | `0.5` | must be above zero | Length of a generated sound effect. A soundscape table can set `duration_seconds` instead. | | `sfx_prompt_influence` | `number` | `0.5` | must be between 0 and 1 | Prompt influence of a sound effect request. A soundscape table can set its own. | | `timeout_seconds` | `integer` | `600` | must be above zero | Seconds before a sound or music request times out. | ## `[output]` These keys switch the files a build writes beside the final mp4. Environment variables start with `DECKTALK_OUTPUT_`. | Field | Type | Default | Value | Meaning | | ------------------ | --------- | ------- | ----- | ------------------------------------------------------------------ | | `timestamped_copy` | `boolean` | `false` | | Write a second copy of the final mp4 named with the date and time. | ## Related * **Set sections, the voice, and the mix:** [decktalk.toml](/reference/decktalk-toml) * **Understand the `[verify]` fields:** [Verify](/reference/verify) * **Override a field for one run:** [CLI](/reference/cli)