Custom Video Player
A branded player with your own controls and colours instead of default browser chrome.
What it adds
A styled playback surface with custom transport controls layered over the app's existing video element.
What your agent is told to do
5
What your agent is told to do
5-
1
Build on the existing video element and the app's Adaptive Media Source Component if it is present. Style and control what is already there rather than introducing a second playback path.
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Ship the controls people use: play and pause, a scrub bar with buffered range, elapsed and total time, volume with mute, captions, playback rate, and fullscreen. Leave out anything you cannot support properly.
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Wire every control to the app's existing Keyboard Interaction Primitives and Focus Ring System. Space and K toggle play, arrows seek and adjust volume, F enters fullscreen, M mutes, and every control shows a visible focus ring.
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Surface caption tracks in the player rather than hiding them. If the app already produces transcripts through Voice Transcription, feed those tracks into this player instead of building a separate caption pipeline.
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5
Do not remove the native controls until the custom ones are proven to work. A player whose custom chrome fails to initialise and has stripped the fallback leaves the viewer with a video they cannot pause.
Edge cases it handles
8
Edge cases it handles
8- Keyboard control is not optional. Play, seek, volume, captions, and fullscreen must all be operable without a mouse, with the shortcuts announced somewhere the user can find them.
- A live stream has no fixed duration, and its seekable range moves as it runs. Show a live indicator and a jump-to-live control instead of a progress bar that implies an ending, and handle the duration changing mid-playback.
- If a caption track, thumbnail sprite, or chapter file fails to load, the player must carry on without it. If the custom chrome itself fails to initialise, restore the native controls rather than leaving a bare video.
- Dragging the scrub bar fires continuously. Seek on release and preview on drag, or the player will issue a request for every pixel of movement and stall the connection it is trying to read from.
- Browsers block autoplay with sound. Detect the rejected play attempt, start muted if that is the intent, and show a clear unmute control rather than a video that appears to be broken.
- The player must reserve its aspect ratio before the video metadata loads, using the app's Media Aspect Ratio System, so the page does not jump when playback becomes ready.
- Fullscreen behaves differently on iOS, which may hand playback to the native full-screen player. Accept that and make sure state returns cleanly when the viewer exits.
- Controls must auto-hide during playback but reappear on any pointer movement, keyboard input, or touch, and must never auto-hide while a control has keyboard focus.
Definition of done
9
Definition of done
9- Play, seek, volume, mute, captions, rate, and fullscreen are all reachable by keyboard with visible focus.
- Live sources show a live state and a jump-to-live control rather than a fixed-duration progress bar.
- A failed caption or thumbnail resource degrades gracefully, and a failed player initialisation restores native controls.
- Scrubbing issues a single seek on release rather than a request per movement.
- Blocked autoplay produces a visible unmute prompt rather than an apparently broken video.
- The player reserves its aspect ratio before metadata loads and the page does not shift.
- Existing transcript and caption tracks are surfaced through this player, not a parallel one.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Hover Video Preview
Hover Video Preview
Hovering a video card plays a short silent clip so people see what it is before clicking.
What it does
A silent, short-loop preview that plays inside a video card on deliberate hover and returns to the poster on exit.
How it works
- 1 Generate a short, low-resolution, silent preview clip during video processing and store it alongside the poster frame. Do not play the full source file behind the card.
- 2 Require a deliberate hover before doing anything. Wait several hundred milliseconds after the pointer settles, then load, so a cursor crossing a grid does not fire a dozen requests.
- 3 Give touch devices an explicit preview control on the card, since hover does not exist there. A long-press or a small preview button is fine; silently doing nothing on mobile is not.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/hover-video-preview
Audio Waveform Scrubber
Audio Waveform Scrubber
Show the shape of a track so listeners can see the quiet and loud parts and click to them.
What it does
A waveform rendered from precomputed amplitude data, doubling as the seek control on the audio player.
How it works
- 1 Compute the amplitude data on the server when the file is first stored, and serve it as a small dataset the page can draw. Do not decode the audio in the browser to build the waveform.
- 2 Replace the plain scrub bar in the app's existing Audio Player with this surface rather than adding a second seek control beside it.
- 3 Draw played and unplayed regions distinctly, and keep the playhead position exact under click, drag, and keyboard seeking on the same surface.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/audio-waveform-scrubber
Video Upload and Encoding
Video Upload and Encoding
Accept a video file and turn it into versions that play in a browser.
What it does
An upload path for video files plus a background pipeline that produces web-playable renditions and a poster frame.
How it works
- 1 Extend the app's existing File Upload rather than adding a second uploader. Video differs in size and in the processing that follows, not in how a user picks a file, and two uploaders means two sets of limits to keep in sync.
- 2 Upload in resumable chunks straight to storage, and enforce size, duration, and type limits on the server. Client-side limits are a convenience, not a control.
- 3 Do the encoding in the app's existing background job system so the user is not holding a tab open, and surface its state through the app's existing Background Job Progress rather than a bespoke poller.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/video-upload-and-encoding
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.