A/B video comparison tool for precise codec inspection
Experience synchronized A/B playback, frame-by-frame stepping, and a draggable slider to inspect two encodings side by side. Vivict, created by Gustav Grusell, runs in the browser and targets video compression engineers, streaming developers, and QA testers. It supports local files, HLS and DASH streams, keyboard shortcuts, and zoom-and-pan for artifact analysis. The web version needs no installation, while Vivict++ offers a native Windows installer and broader codec support via FFmpeg.
What does Vivict let you inspect?
Vivict compares two video sources with synchronized playback and multiple viewing modes: side-by-side, split-screen with a draggable divider, and overlay. The tool supports local file drag-and-drop and URL input including HLS and DASH streams. Frame-by-frame navigation and zoom-and-pan focus allow pixel-level inspection of compression artifacts, and the Slider mode toggles between encodings on a single frame for immediate visual differences.
How reliable is synchronization and playback alignment?
Synchronization is high precision, keeping both videos aligned during playback and seeking, which is critical for visual A/B tests. The web app runs inside modern browsers so codec availability depends on the browser (typical support: MP4, H.264, AV1). For files outside browser-supported codecs, the desktop Vivict++ uses FFmpeg to expand format compatibility.
Is it safe to use with local video files?
Vivict processes files locally in the browser, so video data isn't uploaded to a server when using the web version. The desktop option runs offline. Permission and security exposure are limited to local file access in the browser or the desktop installer; no external upload step occurs during normal operation.
Does it require technical knowledge to operate correctly?
Targeted at specialists, the interface gives keyboard shortcuts, precise seeking, and codec-dependent behavior that assume familiarity with encoding workflows. Casual users can load files and use the basic views, but compression engineers gain most from frame stepping, Slider comparisons, and the desktop version's FFmpeg integration for uncommon formats.
Vivict suits engineers who need focused, visual codec comparison
Vivict is a practical, lightweight option for professionals who must compare encodings visually and require frame-accurate alignment. The main limitation is browser-dependent codec support in the web version, though the Vivict++ desktop build addresses this with FFmpeg support. Use the web build for quick A/B checks and the desktop build when you need broader format handling or offline operation.
