A-B Loop Guide — Video Controls Plus | Repeat Any Section

An A-B loop in Video Controls Plus repeats a chosen segment of a video between two timestamps you set with Alt+A (point A, the start) and Alt+B (point B, the end). Press Alt+L to toggle the loop on or off, Alt+C to clear the markers, and the saved-loops drawer remembers up to twenty loops per video so you can revisit drill points across sessions. The feature works on YouTube, Udemy, Coursera, Vimeo, and most other HTML5 video sites; DRM-protected services like Netflix and Disney+ are supported for playback looping but the saved-loops drawer is disabled there because the player does not expose stable timestamps.

Use cases

Language pronunciation drill

Loop a 5–8 second sentence at 0.75x. Repeat the audio aloud after each replay until your pronunciation matches. Drop to 0.5x for nuance, then back to 1x to confirm.

Music phrase practice

Loop a 4–8 bar passage at 0.5x. Practice the fingering or vocals along with the loop until automatic, then turn off the loop and play through at 1x.

Tutorial step rewatch

Long programming or design tutorials often have a single critical step buried in the middle. Mark A and B around that step and watch it three or four times until you have copied it accurately.

Sports motion analysis

Loop a 2–4 second swing or shot. Combine with 0.25x speed to see frame-by-frame mechanics; reset to 1x at the end of each rep to recalibrate.

Memorizing a long quotation

Loop the 10–15 second segment containing the line. Speak it aloud in unison after each replay until you have it. The brain locks in faster with audio repetition than with reading alone.

How it works

1. Mark start (A). When playback reaches the loop start, press Alt+A. The on-screen overlay shows "A: 0:42" or similar.
2. Mark end (B). When playback reaches the loop end, press Alt+B. The overlay shows the full range.
3. Toggle loop. Press Alt+L to enable or disable the loop. While enabled, the video automatically returns to A every time it reaches B.
4. Clear. Press Alt+C to remove both markers. Necessary before setting a new loop on the same video.
5. Save for reuse. Open the overlay → Saved loops → Save current. Loops persist per video; revisit later from the same drawer.
6. Combine with speed. Speed control still works while looping — drill at 0.5x, confirm at 1x without leaving the loop.

Examples

• A guitar player drilling a 4-bar tab. Alt+A → Alt+B around the 4 bars; Alt+L to start; press 2 to drop to 0.5x; play along until automatic; press = to confirm at 1x.
• A language learner working a long sentence. Loop the 8-second sentence at 0.75x; repeat aloud after each replay; switch to 1x once the rhythm is internalized.

Frequently asked questions

How precise are the loop points?

To the millisecond. The browser exposes currentTime as a float; both A and B are stored at that resolution.

Can I have multiple loops on the same video?

Yes. Save the current loop, then set a new one. The drawer holds up to 20 saved loops per video.

Does the loop survive a reload?

Saved loops do; the active "unsaved" loop does not, by design — most users do not want yesterday's drill point reappearing today.

Why does the loop not work on Netflix?

Loop playback works (Alt+A, Alt+B, Alt+L), but the saved-loops drawer is disabled on DRM-protected services because the player does not expose stable timestamps for resume.

Can I export a loop as a clip?

Not built-in — the extension cannot bypass DRM or save streams. For non-DRM sources, the screenshot tool can capture frames, but full clip export requires a separate downloader the extension does not include.

How do I export saved loops?

Settings → Export → Saved loops. The export is JSON with video URL + A/B timestamps. Useful for sharing drill sets with a teacher or study partner.

What if I set B before A?

The extension swaps them automatically. The loop runs from min(A, B) to max(A, B).

Tips

• For drill workflows, set A a half-second before the actual start. The brain processes audio better when it has a beat of context before the target phrase.
• For language learning, save loops with descriptive names ("subjunctive sentence", "tongue twister 3") so you can revisit them weeks later.
• Combine loop with notes (Alt+. period) to write a one-line goal next to the loop point — useful for music or sports practice.
• When you finish drilling, clear the loop with Alt+C — otherwise the next play session resumes the loop and confuses your past self.

Limitations

• Saved-loops drawer is disabled on DRM-protected services (Netflix, Disney+, Prime Video) because the player does not expose stable timestamps.
• Loops cannot span across separate videos; each loop is bound to a single video URL.
• Loop playback can stutter slightly at the seam if the video bitrate is very high (4K HDR streams) — not all decoders re-buffer instantly. Drop to 1080p or lower bitrate if the seam is jarring.

Last updated 2026-05-06 by Ahsan Mahmood, maintainer.