How to convert MOV to MP4
iPhone and Mac save video as MOV, but Windows, Android, and most websites prefer MP4. Here's how to convert MOV to MP4 free, privately, without uploading your video anywhere.
MOV is Apple's QuickTime container. The video inside is usually H.264 — the same codec MP4 uses — which is why conversion is fast and quality stays identical. You're mostly just repackaging the stream, not degrading it.
Convert MOV to MP4 in 3 steps
- Open JSM-Video.com — the converter loads in your browser, nothing to install.
- Drop your .mov file and make sure the output format says MP4 - Universal.
- Click Convert, then download. If the stars align, the tool uses instant remux (no re-encoding) and it finishes in seconds.
Will I lose quality?
Usually no. When the MOV already contains H.264 video and AAC audio, JSM-Video.com tries a direct stream copy first — the video data isn't touched at all, so quality is bit-for-bit identical and conversion is nearly instant. If your MOV uses an unusual codec (ProRes, HEVC from newer iPhones), it re-encodes to H.264 with the Balanced quality preset, which is visually transparent for normal viewing.
Why not just rename .mov to .mp4?
Renaming the extension sometimes works in VLC but breaks in browsers, editors, and phones, because the container structure differs. A proper remux writes a real MP4 container with correct metadata — do that instead; it takes seconds.
Batch: convert many MOV files
Select up to 10 MOV files at once. Each gets its own card — set MP4 once via the Popular conversions shortcut (MOV → MP4) and hit Convert all. Files convert one after another automatically.
Common issues
- "File is over 1 GB": browser memory limits apply — split the video or use a desktop tool for huge files.
- HEVC/H.265 iPhone video: converts fine, just slower, since it must re-encode to H.264.
- Video plays sideways after conversion: use the Rotate control before converting.
Understanding what's inside your MOV file
Before converting, it helps to know what you're working with. iPhones record MOV files with different codecs depending on settings:
- H.264 + AAC (most common): Default on older iPhones and most Android phones shooting MOV. Converts to MP4 via instant remux — seconds, zero quality loss.
- HEVC/H.265 + AAC (iPhone "High Efficiency" mode): Newer iPhones default to this. Better compression, but MP4 players on older devices may not handle H.265 — so conversion re-encodes to H.264. Slower, tiny quality cost.
- ProRes (iPhone Pro models, "ProRes" toggle): Enormous files, editing-grade quality. Always needs full re-encode to H.264 for sharing.
You can check which you have: on Mac, open in QuickTime → Window → Show Movie Inspector. On Windows, MediaInfo (free) shows the codec in one glance.
Remux vs re-encode: what the tool chooses and why
When you drop a MOV into JSM-Video.com, it first inspects the streams. If it finds H.264 video and AAC audio, it performs a stream copy (ffmpeg -c copy): the compressed data is lifted out of the MOV container and placed into an MP4 container untouched. A 200MB file converts in under 10 seconds with bit-for-bit identical quality.
If it finds HEVC, ProRes, or anything exotic, it falls back to re-encoding with H.264 at the Balanced preset (CRF 23). A 2-minute 4K HEVC clip might take 2-4 minutes on a laptop. The quality loss at CRF 23 is invisible in normal viewing — but keep your original MOV as the master if you plan to edit later.
Settings that matter for MOV conversion
- Output: MP4 Universal — H.264 + AAC, plays everywhere. Don't pick WebM for iPhone footage unless you specifically need it for web.
- Resolution: keep Original unless you need a smaller file. Downscaling iPhone 4K to 1080p is the biggest size lever if the remuxed file is still too large to send.
- Rotate: iPhone videos store orientation as metadata, not baked-in pixels. Some Windows players ignore the metadata flag and show video sideways. If that happens, use the Rotate control during conversion — it bakes the rotation into the pixels permanently.
- Date metadata: Conversion preserves the creation date in most cases, so your Photos library stays sorted.
Batch converting an iPhone camera roll
After a trip you might have 40 MOV clips. Select up to 10 at a time in the converter — each gets its own card. Use the MOV → MP4 shortcut under Popular conversions to set the output on all cards at once, then Convert all. Files process sequentially; a batch of ten 1-minute clips typically finishes in 2-5 minutes since most remux instantly. Download each (or use your browser's multi-download) and you're done.
Frequently asked questions
Will converting MOV to MP4 reduce quality?
Not when the MOV contains H.264 — the tool copies the stream untouched. Re-encoding (for HEVC/ProRes sources) at CRF 23 is visually transparent.
Why won't my MOV play on Windows?
Windows Media Player and many Windows apps lack MOV container support, even when the video codec inside is fine. Converting to MP4 fixes it permanently.
Can I convert MOV to MP4 on my iPhone directly?
Yes — JSM-Video.com runs in mobile Safari and Chrome. Drop the MOV from your Files app, convert, and save back. Everything stays on your phone.
What's the difference between MP4 and M4V?
Almost nothing — M4V is Apple's name for MP4 files, sometimes with DRM on iTunes purchases. For your own footage, MP4 is the interoperable choice.
My converted MP4 has no sound — what happened?
Rare, but some MOVs use PCM or ALAC audio which remuxes fine, while others have an unusual track the copy step skips. Re-run with a full re-encode (change any setting, e.g. resolution) and the audio will be converted to AAC properly.
Should I delete the MOV after converting?
Keep it if it's your only copy of something irreplaceable — the MOV is your master. Delete only duplicates once you've verified the MP4 plays correctly everywhere you need it.