> For the complete documentation index, see [llms.txt](https://memorystring.codebyz.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://memorystring.codebyz.com/build-your-movie/auto-detection.md).

# Auto detection

Three helpers on your Mac — less time muting fridge hum, chasing faces, or typing `IMG_4821`. **Video mute** and **center of interest** on **import**. **Captions** only when you choose **Auto Caption** — never written by itself.

Everything stays on your Mac. Original files are never rewritten.

![Paused photo with the center-of-interest ring](/files/j4d60ddL6NzeAC4Ty31z)

## Video sound (auto-mute)

Speech on camera? Keep it. Wind and empty hallway? Quiet them.

**When:** as each **video** is imported (Essential and Studio). Stills have no clip audio. Soundtrack tracks are not auto-muted.

**First import:** MemoryString may ask **Allow On-Device Speech Detection?**

* **Continue** — then macOS’s Speech prompt. Detection is **on-device**; it does **not** transcribe or save what was said. The system prompt may mention Apple; MemoryString has no cloud speech path.
* **Use Loudness Only** — skip speech. Mute still runs from loudness / tonality.

If you skip or deny speech, later imports keep loudness only (until you reset that preference).

**How it decides** (whole file, not just the start):

1. **No audio track** → muted
2. **Very quiet** throughout → muted
3. If speech is allowed and **speech is found anywhere** in the clip → **stays audible**
4. Else if the energy looks like **music, singing, or cries** (tonal / periodic) → **stays audible**
5. Else **steady non-speech ambience / noise** → muted

There is no toast. A muted clip shows a speaker-off badge in the Library and Timeline.

**Override:** right-click **Mute Video Sound** / **Unmute Video Sound**, the speaker badge, or the Inspector clip footer. Manual mute is yours. See [Library](/build-your-movie/library.md#videos) and [Music](/build-your-movie/music.md#video-sound-not-the-music-lane).

## Center of interest

Eyes, not shoulder. **When:** on **import**, every photo and every video gets a focus point. Cached with the file so reopen keeps the same pick.

**How it picks** (on-device Vision):

1. **Largest usable face** in the frame — aim near the **eyes**, not the chest
2. Else the **main subject** (attention saliency)
3. Else the **middle** of the frame

**Videos:** several frames across the used trim window (not one opening frame). Strongest face / subject wins — a title card or wrong person at the start does not lock focus.

**Override:** pause and click (*Tap photo to set focus*). Ring moves; status shows **Focus · x%, y%**. Drag pans; leaves focus alone. **Reset Center of Interest** (right-click) drops the override and re-runs detection.

![Paused preview: Rotate, Flip, Reset Center of Interest](/files/3oDDDZQAP6EUegojQ5hR)

Ken Burns and punch-in end here; backdrop follows; group cards use it too. Some whole-photo cuts ignore it. Details: [Preview](/build-your-movie/preview.md#center-of-interest).

## Auto Caption

Place and date — not camera codes. Run it: Library captions bubble, **Edit → Auto Caption N Untitled Slides**, Style → Captions, Timeline **Generate**, or a slide’s **Auto Caption**. Not on import.

Untitled-only entry points **never overwrite** what you typed. **Auto Caption All Slides…** overwrites after confirmation.

**How it fills an empty caption**, in order:

1. **Place · date** — GPS on the file (stills: EXIF; videos: QuickTime) reverse-geocoded with Apple’s geocoder, or IPTC city/country if GPS is missing. Format like `Tel Aviv-Yafo · 29 July 2026`. **Country** only when the show has photos from **more than one country**.
2. Else **capture date** — EXIF DateTimeOriginal / video creation date (not the import copy date). Same long-date style.
3. Else a **readable filename** with real words (`dan_and_mom-beach` → `Dan and Mom Beach`). Embedded calendar dates rewritten as dates; clock times dropped.

**Never copied:** UUID / hash names, camera codes (`IMG_1234`, `DSC…`, `Screenshot …`), WhatsApp export titles. Stay blank — better empty than `IMG_4821` as poetry.

Geocoding uses coordinates **already in the media** — not your Mac’s location. Offline still writes date / IPTC captions. One **⌘Z** undoes the whole Auto Caption pass.

See [Intro and captions](/build-your-movie/intro-captions.md#auto-caption).


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