The Quality Problem with Standard Screenshot Methods
When you press PrtScn on Windows or Cmd+Shift+4 on macOS, your OS captures the display buffer — a photograph of your screen. For video, the frame has already been hardware-decoded to the GPU, composited with browser UI, and re-sampled to your monitor's resolution. What gets captured is not the raw decoded frame — it is a downsampled, re-processed version of it. This is why video screenshots from PrtScn look slightly soft even when saved as PNG.
Some browsers also return a black frame for video due to DRM protection. Screenshots Online avoids all of these problems entirely.
How Canvas API Capture Achieves Lossless Quality
Screenshots Online intercepts the video frame directly from the HTML5 decoder output, before any GPU compositing or display scaling. The ctx.drawImage(video, 0, 0) Canvas API call draws the frame at the video's native pixel dimensions. The canvas is then exported as PNG — a lossless format where every pixel is identical to the decoded video frame. No re-encoding, no re-sampling, no quality loss.
Understanding Your Quality Settings
Original (1x) — Use for Most Purposes
Captures at the video's exact native resolution. A 1920×1080 video produces a 1920×1080 PNG. Use this for documentation, archival, and any purpose where you want the exact decoded frame.
High (1.5x) — Use for Cropped Thumbnails
Upscales by 1.5× using canvas interpolation. A 1080p frame becomes 2880×1620. Useful when you need to crop into the image significantly and want extra pixels to work with.
Ultra HD (2x) — Use for Print and Analysis
Doubles the resolution. A 1080p frame becomes 3840×2160. Best for large-format print or detailed analysis of on-screen text. File sizes are 4–8× larger — only use when you genuinely need it.
Choosing the Right Export Format
PNG — Best for Most Uses
PNG is lossless. Every pixel is stored exactly as captured. Use PNG for: thumbnails, graphic design source files, documentation, and any image that will be edited or resized later.
JPEG — Best for Web and Email
JPEG reduces file size dramatically using lossy compression. At 95% quality (what Screenshots Online uses), the visual difference is imperceptible. Files are 5–10× smaller than PNG. Use JPEG for web images where load speed matters.
WebP — Best for Modern Web Apps
WebP achieves smaller file sizes than both PNG and JPEG at equivalent quality. Supported in all modern browsers. Use for web projects where file size is critical.
Tips for Maximum Quality
- Always pause the video before capturing — motion blur is real even in a single decoded frame
- Always work with the highest resolution source file available
- For capturing on-screen text, use PNG and Original resolution for maximum readability
- Avoid dark scenes for text-heavy captures — video encoding allocates fewer bits to dark areas, resulting in more visible noise