Browser Tab Recorder

Record browser tabs with stereo audio. Disk cache for long recording, auto split on screen blackout, and per-segment management.

To those opening the store 👋 Browser Tab Recorder records the selected tab/window/screen and the system/tab audio as a single WebM file using Chrome's screen sharing. Recording, splitting, and saving—all from one pop-up. Key points by section. 【📋 Quick Reference】 ・🎬 Recording: Captures tab, window, or screen + audio into a single WebM using MediaRecorder. ・🆓 Free: Hard limit of 15 minutes per session (enforced in code). ・⭐ Pro: User-defined limits (including unlimited). High-quality audio and automatic splitting are controlled by the UI based on the license. ・💾 Long Recordings: Designed to write small chunks sequentially to IndexedDB, minimizing memory load. ・✂️ Auto-Split: Allows setting split points and recording stops based on matrices of fades/pauses/silence. ・⚙️ Operation: Everything from quality, audio, splitting, to clipping is managed from an extended pop-up (no separate apps needed). 【✨ What This Extension Can Do】 Browser Tab Recorder is an extension that allows you to select a tab, window, or screen from Chrome's screen sharing dialog and record the video and system/tab audio as a single unit. It is ideal for situations where you want to save the visual content displayed on the browser screen as a video file (WebM). We have consolidated the entire process—from recording to splitting to saving—into one pop-up, anticipating uses such as: ・📡 Archiving livestreams and webinars ・📚 Saving online lectures and training sessions ・📋 Screen recording for operational procedures and manuals ・🎯 Reducing the number of retakes for demos ・🎬 Screen recording of long-form videos played in the browser (e.g., anime, dramas, movies) (※Please adhere to the terms of service and copyright of the respective services for viewing and recording) 💡 Tips for Best Results: ・For entertainment videos, fades (scene changes or before/after commercials) and silent sections are easy markers, making them compatible with auto-splitting. You can also select settings that easily capture background music and dialogue in stereo audio. ・In addition to starting/stopping recording, the interface is designed for easy operation without switching screens to a separate app, covering audio quality, video quality, auto-splitting, and saved clips. 【🖥️ Capturing Screen and Audio】 You can overlay a microphone onto the stream captured via screen sharing, if necessary. The microphone is captured as a separate stream from the screen, and the audio tracks are merged into a single bus using Web Audio (AudioContext) before being passed to MediaRecorder along with the video. ・📺 Can record video from a tab or full-screen screen display directly (the sharing range is selected in the OS screen sharing dialog). ・🔊 Mix tab audio and live commentary within the browser (easy to start without needing a virtual audio device). ・🎥 Video sources support combinations beyond screen sharing, including camera only or audio only. 【🎬 Recording Format and Quality】 The core technology is WebM (VP9 video + Opus audio) provided by the browser's native MediaRecorder. ・🔉 Audio (Default): Settings based on approximately 256kbps class. ・📊 Video Bitrate: Selectable from Automatic / Low Capacity / High Quality. ・📐 Resolution: Automatic, or fixed at 1280×720 / 1920×1080. ・🖱️ Cursor: Visible / Hidden (On for operation demos, off for video viewing like movies/dramas/anime, etc.). For video content, selecting a high-quality preset or fixed 1080p makes it easier to retain the detail of the screen video, which can then be organized as a "reviewable video file" alongside stereo audio. 【🎧 Audio Quality and Modes】 We prioritize "high-quality listening," so recording defaults to having echo removal, noise suppression, and automatic gain set to off. ・🎚️ Sample Rate: Default is 48kHz. Can be changed via the UI to 44.1kHz / 32kHz / 22.05kHz, etc. ・🎛️ Channels: Default is Stereo (2ch), but can be switched to Mono. ・🎤 Input Mode: Tab Audio Only / Tab + Microphone. ・📈 It is easy to start recording after confirming input levels with the level meter, preventing inputs that are too quiet or too clipped. 【⏱️ Long Recording, Storage, and Limits】 To prevent the data from accumulating only in memory, recording data is divided into small chunks and written sequentially to IndexedDB. ・🧠 Minimizes memory pressure even during long programs or meetings. ・💾 If IndexedDB writing fails, it falls back to memory, attempts to continue while notifying the user. ・🛡️ The fallback mechanism has a memory limit and a guard to stop excessive growth. ・⏰ Recording time limits are specified in "Hours + Minutes" and automatically stop upon reaching the limit. ・🔢 A countdown before starting allows time for preparation and microphone checks. ・⏸️ When paused, the limit timer also stops, and the remaining time is reset upon resuming. 💎 Free / Pro (Key Points) ・🆓 Free: Hard limit of 15 minutes per session, enforced in code. ・⭐ Pro: Removes the above constraints, allowing user-defined limits (including unlimited). ・📜 High sample rates, high resolutions, high bitrate video, and automatic actions (fades/pauses/silence) are controlled by the UI based on the license (Refer to the in-app guide for details). 【🌑 Fade Detection and Manual Splitting】 ・📊 Displays average luminance during recording, making it easy to adjust the fade threshold visually. ・✂️ Even if not using auto-split, the internal structure is always segment-based. Manual splitting is also possible if needed. ・📥 Confirmed segments can be previewed and downloaded from the list (easy to handle as "split clips" before editing). 【✂️ Auto-Split (Fade / Pause / Silence)】 You can set splitting and recording stops based on a matrix using three criteria: fade, pause, and silence. 🌑 Fade ・Calculates average luminance on the canvas by sampling frames intermittently. ・A segment is a candidate for splitting if the "dark" state (below the threshold) persists for a set time. ・Options are available to reduce false splits, such as only considering a fade when the audio is silent, or not judging until X minutes have passed from the segment start. ・After splitting, there is a short cool-down period (to prevent excessive small clips from continuous transitions). 🖼️ Pause ・Detects when the change in video is small and sustained. ・Detailed conditions can be selected, such as including silence as a condition. 🔇 Silence ・Detects when the energy in the frequency domain remains below a threshold. ⚙️ Common ・For each condition, you can individually specify "split after X seconds" or "stop there." ・Assignment is possible not only for splitting but also for "recording termination" (e.g., automatic stop after abandonment/unattended period). ・The behavior of stopping recording when the video track ends is also considered. 【🔗 Segment Management and WebM Merging】 ・📑 Each segment retains the reason for splitting (Initial / Fade / Pause / Silence / Manual, etc.), a sequential number, length, and an optional name. ・💾 The segment list can be restored from IndexedDB even after closing the pop-up. ・🧩 Since simple concatenation of multiple WebM files can easily corrupt the EBML, we interpret Matroska/EBML and merge them into a correct single file with consistent cluster timing (also correcting end clusters derived from streaming before merging). 【🎛️ Operation UI and Licensing】 ・⏱️ Elapsed time, pause/resume, activity log, toast notifications. ・📂 Settings are organized using an accordion (e.g., video quality, audio, fade, auto-split matrix). ・🔑 Available features switch based on the license. ・☁️ License verification links to Firebase authentication and cache (Refer to the product version screen for details). 【🔒 Data Handling (Privacy Guidelines)】 ・💾 The recorded content is stored in IndexedDB/Memory. ・👆 Saving and downloading clips require user action. ・🏠 Since this is not a recording pipeline that automatically sends video files to the cloud, it is best suited for uses where you want to keep the content locally first (e.g., internal procedures, unreleased content). (Communication may occur during authentication or license verification). ・🏢 File storage and sharing must comply with organizational policies. 【🛠️ Design Goals】 We prioritize using browser standard APIs and lightweight logic, making it difficult to break by focusing on: long duration = chunk sequential writing + memory guard, and merging = EBML consistency. We aim to make it easy to retain reliable files using only the browser, even if they are intended to be re-encoded later with external tools. 【💡 Suggested Scenarios and Tuning Tips】 ・📡 Live / Webinars: Easy to structure chapters using fades and silence, making it easy to hand off units to editing software. ・🎬 Anime / Dramas / Movies (Browser Playback): Fades are useful markers for scene changes or blocks (OP/ED areas, commercials, etc.). Silence and pauses can also be used to mark title rolls or static cut breaks. Long recordings are easy to handle with IndexedDB and splitting, and stereo audio helps retain the atmosphere of music, sound effects, and dialogue (Please use within the scope of rights and regulations). ・🖱️ Operation Demos: Intent is easily conveyed with cursor + tab audio + microphone commentary. ・🎓 Classes / Training: Use IndexedDB for stable long-form recording while balancing the free 15-minute limit with the Pro limit relaxation. ・📶 Quality Presets: From low-bandwidth settings for mobile viewing to high bitrate for large-screen viewing. The optimal values for automatic detection depend on the tempo and lighting of the program. It is best to experiment with the target content to determine the thresholds, continuation times, segment head grace periods, and seconds for pause/silence. Combinations like "split on fade but don't stop on silence" can also be adjusted. Toast notifications and activity logs make it easy to track "where it was split" after a long recording. 【📝 Summary】 Browser Tab Recorder is an extension that not only saves video displayed on the browser screen in high quality but also covers the entire operational workflow: stable long-term recording, splitting/stopping based on fades/pauses/silence, managing segments without loss, and merging them into a correct WebM. It covers a wide range of use cases, from business applications to organizing entertainment videos like anime, dramas, and movies. Starting with short test recordings to gauge the feel of quality, audio, and auto-splitting helps reduce issues during live use. ⚠️ Disclaimer: Depending on the Chrome Web Store review and display space, the boundaries, limits, and expressions between free and paid features should be adjusted according to the product's internal labeling and policies at the time of publication. Browser Tab Recorder is an extension that records video displayed on the browser screen as a video file with high-quality stereo audio. It is particularly compatible with screen recording of long-form videos like anime, dramas, and movies, and its strength is the easy auto-splitting based on fades or silence (Please adhere to the terms of service and copyright of the respective services for use and recording). ・💾 Stable long-form video recording via chunk writing to IndexedDB. ・🎚️ Flexible audio settings: Sample rate / Mono-Stereo / Tab Only / Tab + Mic. ・✂️ Auto-splitting and segment management based on fades, pauses, and silence (easy to mark video breaks). ・🔗 WebM merging considering EBML (combining multiple clips into one video). This is a highly functional extension with all the features listed above.