Why use Nyxhora for this workflow
Edit MP4 files natively — no conversion needed for most operations, preserving original quality
Trim, split, add captions, transitions, and text overlays to MP4 files in a timeline editor
Export as MP4 (H.264) at the same or different resolution — compatible with every platform and device
Why MP4 is the format you should always use
MP4 with H.264 encoding is the universal standard. Here is why: COMPATIBILITY: every device, platform, browser, and video player supports MP4. YouTube, Instagram, TikTok, Twitter, LinkedIn, Facebook, WhatsApp, email — all accept MP4. QUALITY: H.264 offers excellent quality-to-size ratio. Better compression than older formats (AVI, WMV, MOV with ProRes). SIZE: efficient compression means smaller files without visible quality loss. EDITABILITY: most editors (including Nyxhora) can trim MP4 without re-encoding — lossless cuts in seconds. STREAMING: MP4 supports progressive download and adaptive streaming. THE RULE: if you do not know what format to use, use MP4. It is always the safe choice. The only reasons to use other formats: ProRes for professional editing workflows, WebM for web-optimized transparency, MOV for Apple ecosystem compatibility.
Editing MP4 without re-encoding (lossless trims)
One of MP4's underappreciated features: you can trim it without re-encoding. When you set trim points (in/out), Nyxhora can adjust the MP4's start and end markers without decoding and re-encoding every frame. This means: a 1GB MP4 can be trimmed in seconds, not minutes. Quality is preserved exactly — no generational loss. File size reduction is proportional to the trim. WHEN LOSSLESS TRIM WORKS: cutting the start or end of the file. WHEN RE-ENCODING IS NEEDED: splitting in the middle (requires frame decoding), adding effects or transitions, adding captions or text overlays, changing resolution. PRACTICAL IMPACT: if you just need to trim dead air from the start and end of a recording, Nyxhora does it instantly without quality loss. If you need to add captions or effects, re-encoding is required but quality loss is minimal at high bitrate settings.
MP4 compatibility across every platform
Here is the actual compatibility data: YOUTUBE: MP4 (H.264) is the recommended format. Upload at your recording resolution. INSTAGRAM: MP4 (H.264) with AAC audio. 1080x1920 for Reels. TIKTOK: MP4 (H.264) with AAC audio. 1080x1920 for vertical. TWITTER/X: MP4 (H.264) up to 512MB. Max 2:20 duration. LINKEDIN: MP4 (H.264). 1:1 or 9:16 recommended. FACEBOOK: MP4 (H.264). Supports long-form and Reels. WHATSAPP: MP4 (H.264). Max 16MB for sharing. EMAIL: MP4 supported in most clients, but GIF may be better for auto-play. APPLE: QuickTime supports MP4 natively. WINDOWS: Windows Media Player supports MP4 with H.264. THE BOTTOM LINE: MP4 works everywhere. If a platform accepts video, it accepts MP4.
Changing resolution when editing MP4
Nyxhora lets you export at different resolutions than the source: DOWNscaling: 4K source → 1080p export. Quality improves slightly due to supersampling. File size decreases significantly. UPscaling: 1080p source → 4K export. Quality does NOT improve — you are just making pixels larger. Only do this if the platform requires 4K. SAME resolution: keep source resolution. Best quality preservation. WHEN TO CHANGE: 4K source for social media → export at 1080p (platforms compress to 1080p anyway). 1080p source for YouTube → keep 1080p (YouTube handles the rest). 720p source for presentations → export at 1080p (slight upscale helps on projectors). THE RULE: downscale when the platform compresses anyway. Keep original when quality matters. Never upscale expecting quality improvement.
How it works
Import your MP4 file
Drag and drop your MP4 file into the editor, or click to browse and select from your device. The editor loads MP4 files instantly — no conversion or upload.
Edit the video
Use the timeline to trim, split, rearrange clips. Add captions, text overlays, transitions, and audio adjustments. All edits happen in real-time in your browser.
Export as MP4
Click Export and select MP4 format. Choose target resolution and quality. The edited video encodes to MP4 and downloads to your device.
Frequently asked questions
Is there a file size limit?
Processing is in-browser, limited by device memory. Most devices handle MP4 files up to 2GB without issues. For very large files, ensure you have enough free RAM (8GB+ recommended).
Does editing reduce quality?
Simple trims can be lossless (no quality change). Effects, captions, and transitions require re-encoding with minimal quality impact at default export settings. The quality difference is typically imperceptible.
Can I change resolution when editing?
Yes. Export at original resolution or scale to 720p, 1080p, or 4K. The editor scales frames to fit. Downscaling is fine. Only upscale if the target platform requires it.
What MP4 settings should I use for export?
Default settings (H.264, AAC audio, match source resolution) work for most use cases. For YouTube, export at your recording resolution. For social media, 1080p at default quality is optimal.
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