Introduction

What this app is for

MultiAngleVideoPlayer plays several videos of the same event side by side, in perfect step with each other. It was built for race review: a race is usually filmed from more than one camera, and the useful questions — did that horse shift ground, when exactly did the interference happen — are answered by watching two or three angles of the same moment together, frame by frame.

Ordinary video players can’t do this. Even if you open three players and press play at the same time, the videos drift apart, and there is no way to step all of them back one frame together. This app treats the loaded videos as one group: one play button, one timeline, one frame-step that moves every angle at once.

The core idea: a shared zero point

The camera files never start at the same instant. One camera might start recording 12 seconds before the race jumps, another 15 seconds before. So “3 seconds into the file” is a different real-world moment in every file.

The app solves this with a zero point: you pick one moment of the event — typically the start of the race — and mark where that moment is in each video. From then on the app knows each video’s offset (how far into that file the zero point sits) and can line all of them up on a single shared timeline that reads 0:00 at the zero point.

You only do this alignment once per set of videos, and you can save the result as a package and reopen it later exactly as you left it. The zero point, offsets, and the two modes are the concepts a new user most needs to understand; they get a chapter of their own next (chapter 3).

The two modes, in one paragraph each

The app has two modes, switched with the two buttons at the left of the transport bar:

Unlock Mode is for getting ready: loading videos, moving each one independently, and marking the alignment. Each tile plays on its own; clicking a tile selects it (red border) and the transport bar drives just that tile. The time it shows is that one selected video’s own time.

Lock Mode is for reviewing: every loaded video moves together on the shared timeline. Play, pause, scan and frame-step act on all tiles at once, and the time display shows time since the zero point — the race treated as one timeline. This is the mode you’ll spend most of your time in, and the app opens in it.

The mental model: Unlock to line them up, Lock to watch them together. Chapter 3 covers both modes in detail, with a complete worked example.

A quick tour of the window

From top to bottom:

• Top toolbar — the race details (discipline, track, date, race number), the layout buttons, and a clipboard-timecode toggle; then, on the right: the app version (click it for the changelog), a button that labels each tile with its file name (chapter 6), a scrub-mode toggle (chapter 7), the GPU-memory indicator, and a cluster of tool icons — the track database, mouse setup, settings, and the status display.
• Video area — the tiles, one per video, arranged by the chosen layout. One tile is always the selected tile, shown by a coloured border (blue in Lock Mode, red in Unlock Mode). The selected tile is the one you hear.
• Transport bar — everything that controls playback: mode buttons, open/save buttons, play/pause, scans, frame steps, the timeline slider, volume, Fast Seek, and the Detach button that floats the whole bar into its own window.

What’s in this manual

The chapters are ordered to be read straight through the first time, then dipped into later:

• Concepts — the zero point, offsets, and Lock vs Unlock Mode (chapter 3). Read this one.
• Preparing footage — splitting a single multi-angle file into separate videos (4).
• Everyday use — loading videos (5), tiles and layouts (6), playback and the transport (7), timecodes and the clipboard (8).
• Sessions — packages (9) and the track database (10).
• Performance — Fast Seek for smooth backward scrubbing (11), and GPU memory, which is a genuine operational issue on a busy machine (12).
• Setup and extras — mouse configuration (13), settings (14), the detachable transport (15), the status display (16).
• Reference — quick tables, troubleshooting, and an expanded FAQ (17).
• Appendix — installing FFmpeg manually and adding it to the Windows PATH (18). Not needed for normal use; only for the two optional features that call the FFmpeg command-line tools, or if you want FFmpeg available system-wide.