ClipComposer Support

Help and troubleshooting for ClipComposer — the photo and video slideshow maker.

Getting Started

Build a slideshow in four steps.

1. Add your photos and movies

Click the + button in the toolbar and choose From Finder… to pick files from anywhere on your Mac, or From Photos Library… to browse your system Photos library without leaving the app.

You can also drag files straight from Finder onto the list on the left. ClipComposer accepts any photo or movie format macOS can read.

• Drop an audio file onto the list and it becomes the music bed.
• Items are added at the end of the slideshow — drag them to reorder.
• Click any item in the list to jump the preview to that point instantly.

2. Set how long each photo shows

Select a photo and set Time on screen in the inspector. Movie clips play for as long as you trim them to, so they have no separate duration.

• To change all photos at once, set Default photo time under the Project tab, then click Apply to All Photos.

3. Preview it

Press Play, or the Space bar, to watch the whole slideshow with its audio. Drag the scrubber, or click anywhere in the segment bar above it, to jump around.

The preview uses exactly the same renderer as the export, so what you see is what you get.

4. Export

Choose File ▸ Export Movie, pick a format and size, and choose where to save. ClipComposer writes a QuickTime .mov file.

Adding Photos & Videos

From Finder

Click the + toolbar button and choose From Finder…, or drag files directly onto the item list. You can add multiple files at once.

• Dropping an audio file onto the list adds it as the music bed instead.
• Supported formats: JPEG, HEIF, PNG, TIFF, and any movie format AVFoundation can read (including MP4, MOV, and M4V).

From Photos Library

Click the + toolbar button and choose From Photos Library…. The system photo picker lets you browse your library, albums, and favourites without granting the app access to your entire library.

Working with items

• Drag items in the list to reorder them.
• Right-click an item and choose Duplicate to create a copy — useful when you want to use two separate parts of the same clip.
• Select multiple items with Shift-click or Command-click to apply settings to all of them at once using the multi-select controls in the inspector.
• Click any item in the list and the preview jumps to that point in the slideshow.

Relinking moved files

If the original file has moved somewhere ClipComposer can’t follow, the item is dimmed in the list and shows a Missing badge. Select it and click Relink File… in the inspector to point it at the new location.

Timing & Crossfades

Photo duration

Each photo has its own Time on screen. Default photo time under the Project tab is what new photos get when you add them — changing it later doesn’t affect photos already in the list unless you click Apply to All Photos.

Crossfades

Crossfade under the Project tab sets how long each item takes to fade into the next. Set it to 0 for hard cuts. Any individual item can differ: turn on Crossfade in for that item in the inspector and give it its own length.

Why crossfades make the slideshow shorter

A crossfade overlaps two items rather than sitting between them — the next item starts before the previous one has finished. So the finished movie runs for the sum of the durations minus the sum of the crossfades.

• Five items of 3 seconds each = 15 seconds of material.
• With four 1-second crossfades between them, the export is 11 seconds.

Very short items

A crossfade is never allowed to be longer than the items on either side of it, and never long enough to put three items on screen at once. If you ask for a 5-second crossfade either side of a 1-second photo, ClipComposer quietly shortens it to fit.

Reading the timeline bar

The strip above the scrubber shows the running order. Each block is one item — movie clips are the darker ones — and the orange sections at the leading edge of each block are the incoming crossfades. Below the segment bar, a thin green strip shows where the music track plays, with gradients at either end representing the fade-in and fade-out.

Photo Motion

Turning it on

Open the Project tab in the inspector and set Photo motion. Choose a direction — Zoom In, Zoom Out, or a pan direction — or choose Random to give each photo its own move. Amount controls how far the move travels across the photo’s time on screen.

Per-photo control

Select a photo and set Motion in the inspector to give it a different move from the rest, or set it to None to hold that one still while the rest of the slideshow moves.

Moving photos fill the frame

A photo that moves is always scaled to cover the whole frame, even when Scaling is set to Fit. Panning a letterboxed photo would drag its black bars around with it, which looks wrong — so a moving photo is cropped instead.

Random moves are stable

Random assigns a move per photo, not per playback. The same photo gets the same move every time you preview, every time you export, and after you save and reopen the project. Adding a photo again as a new item gives it a fresh random move.

Movie clips

Motion applies to photos only. Movie clips already move, so they’re left alone.

Movie Clips

Trimming

Select a clip and set Start at and End at. Plays for shows the resulting length, which is what the clip contributes to the slideshow.

• Trimming is a single in-and-out point — there’s no way to cut a clip into several pieces in one item.
• To use two parts of the same movie, add it twice and trim each copy. Right-click the item and choose Duplicate for a quick copy.

Sound

A clip keeps its own audio by default. Use Volume to balance it against the rest, or tick Mute this clip to drop it entirely. Clip audio fades in and out along with the picture whenever there’s a crossfade.

Rotation

Clips filmed in portrait come out the right way up — ClipComposer reads the rotation metadata recorded in the file.

Music

Adding a track

Click Choose Music… in the Project tab of the inspector, or drag an audio file onto the item list. The track plays under the entire slideshow. MP3, AAC, AIFF, and WAV files are all supported.

Fades and looping

Fade in and Fade out set how long the music takes to come up at the start and drop away at the end. Repeat to fill the slideshow loops a short track until it covers the whole thing — with it off, the music simply stops when it runs out.

Ducking under movie clips

Lower under movie clips drops the music volume while a clip’s own audio is playing, then brings it back afterwards — so speech in a video clip isn’t buried under the music. Lowered volume sets how far down it goes.

• Clips you’ve muted don’t trigger ducking.

Reading the music strip

A thin green strip appears just below the segment bar whenever a music track is loaded. It shows where the music plays relative to the slideshow. Gradients at the left and right ends represent the fade-in and fade-out. If Repeat to fill the slideshow is on, the strip spans the full timeline.

Captions

Adding a caption

Select an item in the list, open the Item tab in the inspector, scroll down to the Captions section, and click Add Caption. Click the disclosure arrow next to a caption to expand its controls.

• Each slide can have multiple captions.
• The trash button on a caption row removes it.
• Captions are rendered directly into the video frames on export — viewers don’t need any special player to see them.

Font, size, and style

The Font picker offers a curated list of fonts that work well on video — Helvetica Neue, Futura, Georgia, Impact, and more. Size is calibrated to a 1080-pixel canvas height, so a 54-point caption looks the same relative size at 720p, 1080p, and 4K. Toggle Bold to switch between the regular and bold face.

Position

Left — Right moves the caption horizontally. Bottom — Top moves it vertically, with 0 at the bottom and 1 at the top. The default position (horizontal centre, 12% from the bottom) matches the conventional caption area for most video formats.

Color and shadow

Use the Color picker to set the text color. Drop shadow adds a soft shadow that helps text stand out against busy backgrounds.

Background box

Background slides from 0 (transparent) to 1 (solid). When it’s above 0, a filled box appears behind the text and a Background color picker lets you choose its color. A semi-transparent dark box is a common alternative to a drop shadow on very textured backgrounds.

Captions and crossfades

Each caption belongs to one slide and fades in and out with it. When a slide dissolves into the next, its captions dissolve with it — a caption will never hang in the air over someone else’s photo.

Exporting

Choosing a format

• H.264 — the most compatible choice. Use this for sharing via email, social media, or any web player.
• HEVC (H.265) — smaller files at the same quality, but requires a reasonably recent player. Good for local storage and AirDrop.
• Apple ProRes 422 — very large and near-lossless. Use it when the movie is going into Final Cut Pro, DaVinci Resolve, or another video editor.

Size and frame rate

• 720p (1280 × 720) and 1080p (1920 × 1080) — standard widescreen.
• 4K (3840 × 2160) — for large screens or future-proofing.
• Square (1080 × 1080) — Instagram feed posts and similar square formats.
• Vertical (1080 × 1920) — Instagram Reels, TikTok, YouTube Shorts, and other 9:16 vertical formats.
• Custom — type any width and height.
• 30 fps suits most slideshows. Choose 60 for very smooth motion, or 24 for a cinematic look.

While it runs

The export sheet shows progress and a rough time remaining. Stop cancels the export and removes the partially written file — it won’t leave a broken movie behind. Exporting is faster than real time on most Macs; a 4K ProRes export is the slowest case.

Estimated file size

The size shown before you export is an estimate based on the format, frame size, and duration. The real file is usually smaller, because still photos compress extremely well in video codecs.

Saving Projects

Project files

Save writes a .clipcomposer file. It stores the running order and all your settings — not the photos and movies themselves, which stay where they are on disk.

Open Recent

Recently opened and saved projects appear under File ▸ Open Recent, just like any other document.

Undo and Redo

ClipComposer tracks up to 50 steps of history for the item list, project settings, and music. Press ⌘Z to undo and ⇧⌘Z to redo. Rapid changes — like dragging a slider — are grouped into a single undo step.

• Undo history is cleared when you open a different project or create a new one.
• Undo and Redo are also available in the Edit menu.

Moved files

If you move a photo or video after saving, ClipComposer will usually still find it — it records a security bookmark in addition to a path. Anything it genuinely can’t find is dimmed in the list and marked Missing. Select it and click Relink File… in the inspector to point it at the new location. All settings are kept.

Troubleshooting

The movie is shorter than I expected

Crossfades overlap items rather than sitting between them, so they shorten the total runtime. See Timing & Crossfades above for the details. The length shown next to the window title is always the true finished length.

A photo is cropped when I want to see the whole thing

Either Scaling is set to Fill, or that photo has a motion style set — moving photos always fill the frame to avoid panning black bars. To see the full photo: set Scaling to Fit (in the Item tab of the inspector) and set that photo’s Motion to None.

An item is dimmed and says “Missing”

The original file has been moved to a location ClipComposer can’t follow, or deleted. Select the item and click Relink File… in the inspector to point it at the new location. If the file is truly gone, remove the item and add it again from its new location. All settings are preserved through a relink.

There’s no sound in my export

• Photos are silent — a slideshow made entirely of still photos with no music bed has no audio track at all.
• Check that the video clip isn’t muted, and that its Volume isn’t set to zero.
• If the music goes quiet under a video clip, that’s Lower under movie clips doing its job — adjust or turn off that setting in the Music section of the Project tab.
• Check that the music track volume slider isn’t at zero.

My captions don’t appear in the export

Captions are rendered directly into the video frames, so they should always appear. Check that:

• The caption’s text field isn’t empty.
• The text color isn’t the same as the background (e.g. white text on a white slide).
• If Background is set to 0 and Drop shadow is off, light-colored text against a light background can be invisible — try a darker color or turn on Drop shadow.

My vertical or square export looks wrong

Switching from a widescreen preset to Square or Vertical changes the frame shape, which changes how photos are cropped or letterboxed. Open the preview, check each slide, and adjust Scaling (Fit vs Fill) and any per-item overrides before exporting.

Preview stutters on a large project

The preview renders at a reduced size to stay responsive, but many 4K video clips can still be demanding. Scrubbing through movie clips is slower than scrubbing through photos because each jump must seek through a video file. The final export is unaffected — it always renders at full quality regardless of preview performance.

A project I saved won’t open

Make sure the .clipcomposer file hasn’t been renamed to a different extension. Double-clicking it in Finder should open ClipComposer automatically. If the app opens but shows an error, the project file may be corrupted — check that it wasn’t saved to a network drive or cloud folder that interrupted the write.

I need more help

If something isn’t covered here, contact support and include a description of what you were doing when the problem occurred, your macOS version, and whether the issue is repeatable.

Keyboard Shortcuts

Keys	Action
⌘N	New slideshow
⌘O	Open a project
⌘S	Save
⇧⌘S	Save As
⌘Z	Undo
⇧⌘Z	Redo
⌘I	Add photos and movies from Finder
⇧⌘M	Choose music
⌘E	Export movie
⌘P or Space	Play or pause
⌘?	Open in-app help