Question 1

Is recording my screen online safe? Will my video be uploaded to any server?

Accepted Answer

100% safe and processed entirely on your local machine!

① Client-Side Architecture:
This tool utilizes the browser-native Screen Capture API and MediaRecorder API. All video capture, audio track mixing, and encoding occur within your local device memory.

② Zero Cloud Uploads:
Without your explicit action, no data is ever transmitted to a server. Even when using PRV5 private share, the file is handed over directly between browser tabs via postMessage memory transfer without touching intermediary proxy servers.

Question 2

How do I capture both system audio and my microphone commentary simultaneously?

Accepted Answer

This tool incorporates real-time Web Audio API track mixing:

① System Sound:
When the browser prompt appears after clicking "Start Recording", choose "Entire Screen" or "Chrome Tab" and ensure the "Also share system audio / tab audio" checkbox is enabled.

② Microphone Voiceover:
Enable "Record Microphone Voiceover" in the settings and select your desired microphone hardware. The tool combines both inputs into a unified stereo stream seamlessly.

Question 3

What screen resolutions are supported? Does it work with 4K or ultra-wide (21:9) monitors?

Accepted Answer

All native display resolutions and aspect ratios are fully supported:

① Native Pixel Capture:
We do not hardcode or downscale width and height constraints. Capture runs at full native resolution, including 1080p, 2K, 4K, 32:9 ultra-wide displays, and vertical secondary monitors.

② Responsive Viewport:
The preview player utilizes an adaptive aspect container that naturally scales to any aspect ratio without black-bar cropping or stretch distortion.

Question 4

What video format is produced? Why is WebM (VP9/Opus) preferred?

Accepted Answer

Modern video codecs are selected dynamically based on browser capabilities:

① Modern Open Standard:
On Chrome, Edge, and Firefox, Google VP9 video with Opus high-fidelity audio packaged in WebM is selected by default. VP9 provides superior compression compared to legacy H.264, preserving sharp text edges at smaller file sizes.

② Safari & Apple Ecosystem Compatibility:
On macOS and iOS Safari, the recorder automatically switches to MP4 (H.264/AAC), ensuring broad cross-device playback compatibility.

Question 5

Why do some online WebM recordings lack a seekable timeline, and how is it fixed here?

Accepted Answer

This addresses a known long-standing Chromium MediaRecorder quirk:

① The Root Cause:
Because real-time recording duration is unknown in advance, Chromium outputs WebM files with an unknown Segment Duration in the EBML header, causing media players to disable scrubbing and timeline jumping.

② In-Memory Header Patching:
Upon completion, our engine inspects the EBML structure at the byte level and injects the exact duration in milliseconds into the Segment Info block. The body data is rejoined zero-copy via Blob.slice, ensuring instant seekability in VLC, QuickTime, and web players.

Question 6

Are there file size limits when using "Send to PRV5 Private Share"? How does it work?

Accepted Answer

Smalltools enforces no file size hard cap on the sending side:

① Cross-Window Handshake:
Clicking share opens the dedicated PRV5 receiver tab. The two windows verify identity using strict origin matching before transferring the in-memory File object via postMessage.

② Quotas Enforced by PRV5:
Smalltools does not artificially limit your video size. All transfer limits conform to PRV5 policies (2.5 GB for guest uploads, 5 GB for registered accounts), providing seamless recording and sharing.

Question 7

Will recording long sessions consume all my computer memory?

Accepted Answer

Keep browser tab memory limits in mind for very long sessions:

① In-Memory Buffer Model:
Pure client-side recording stores encoded chunks in browser memory. At 2.5 Mbps, one hour of video produces approximately 1.1 GB of data, which modern computers handle with ease.

② Single-Session Memory Hygiene:
To prevent tab crashes from runaway memory consumption, this tool maintains a single active recording. Clicking "Record Again" promptly revokes the previous Blob URL to prevent leaks. For multi-hour marathons, consider recording in chapters or using "Storage Saver" mode.

Online Screen Recorder

Audio Input & Voiceover Settings

Frequently Asked Questions & Guide7 Q&As