The Best Video Format for Every Situation

"What format should I use?" is really several different questions wearing one coat. The answer for a WhatsApp clip is the opposite of the answer for an editing master. What changes is which quality you're optimising for: compatibility, small size, editability, or long-term storage. Work out which one matters for your destination and the format almost picks itself.

Messaging apps (WhatsApp, Telegram, Signal)

Use: MP4 / H.264, 720p, AAC audio. Messaging apps care about two things — universal playback on the recipient's phone and staying under an upload cap (WhatsApp's is around 16 MB for a standard send). H.264 in an MP4 plays on every phone, and dropping to 720p with a sensible quality level usually gets a short clip comfortably under the limit without looking bad on a handset screen — OpenConvertVideo's WhatsApp preset applies exactly this recipe in one click. Skip HEVC here — even though it's smaller, some recipients' phones won't decode it.

Email attachments

Use: MP4 / H.264, kept small — or don't attach it at all. Most email providers cap attachments at 20–25 MB, and large attachments are bounced or clog inboxes. A short, well-compressed 720p MP4 is the safe attachment — OpenConvertVideo's Email preset applies exactly that recipe in one click. For anything longer than a few seconds, genuinely consider uploading it somewhere and sending a link instead — it's a better experience for everyone and sidesteps the size limit entirely.

Social platforms (YouTube, Instagram, TikTok)

Use: MP4 / H.264 (or HEVC) at a high bitrate, correct aspect ratio. Every platform re-encodes whatever you upload into its own formats, so your only job is to hand them a clean, high-quality source they can work from. Upload at full resolution and a generous bitrate — starving the file to save space here is counterproductive, because the platform's re-encode will compound any loss. Match the aspect ratio to the destination (vertical 9:16 for Reels/TikTok, 16:9 for standard YouTube) so nothing gets cropped or letterboxed — OpenConvertVideo's Instagram preset handles this automatically.

Video editing

Use: an edit-friendly codec — ProRes or DNxHD ideally; failing that, H.264/HEVC that you accept will be sluggish. Here's a subtlety most people miss: the codecs that compress best are the worst to edit. HEVC and long-GOP H.264 store most frames as differences from their neighbours, so an editor has to reconstruct a lot just to show you a single frame — which makes scrubbing and cutting stutter. Professional "intermediate" codecs like ProRes are larger but store every frame whole, so editing is smooth. If you're editing seriously, transcode to an intermediate first; if you're doing something light, plain H.264 will work, just don't expect buttery scrubbing from a heavily-compressed phone clip.

Long-term storage and archiving

Use: HEVC if you control playback; otherwise keep H.264 or the original. For archiving, size matters and you're often willing to trade a little compatibility for it — HEVC roughly halves the storage a library takes. The counter-argument is future-proofing: H.264 is the format most certain to still play effortlessly in twenty years. A reasonable middle path is HEVC for bulky 4K footage where the space saving is large, and leaving already-small H.264 files as they are.

Self-hosting on the web

Use: MP4 / H.264 as the baseline, optionally WebM / VP9 (or AV1) alongside. If you're embedding video on your own site, H.264 in MP4 is the one source every browser can play, so it's your safety net. To save bandwidth you can additionally provide a VP9 or AV1 version and let the browser pick the more efficient one it supports. If you only want to ship one file, ship the MP4.

Quick reference

When in doubt

If you can't be bothered to reason it through, MP4 with H.264 video and AAC audio is the answer that's never wrong — it may not be the smallest or the most editable, but it will play, upload and share anywhere. Reach for something more specialised only when you have a specific reason: a tight size limit, a serious edit, or a large archive to store.

The takeaway

The "best" format is a function of the destination, not an absolute. Decide whether you're optimising for compatibility, size, editability or longevity, pick accordingly — and keep MP4/H.264 in your back pocket as the choice that always works.