Platform Requirements for Video: Formats, Limits and What Happens on Upload

A clip that looks excellent on your computer can turn soft, jerky or cropped after upload. Each platform processes uploads by its own rules, and knowing them saves rework.

What happens to a file on upload

Platforms almost always transcode video: converting to their codec, bitrate and sometimes resolution. The goal is uniform playback and bandwidth economy, not preserving your quality.

Hence a practical consequence: upload with quality to spare. A file you compressed will be compressed again, and the losses add up.

Aspect ratio

The commonest cause of a ruined result. The platform will crop or add bars if the format does not match what it expects.

• Short vertical formats: 9:16, full screen.
• Social feeds: 4:5 or 1:1 — they occupy more screen height than horizontal.
• Horizontal platforms: 16:9.
• Profile covers: each platform has its own proportions, and they differ between mobile and desktop.

Safe zones

The interface covers the frame edges. At the top, indicators and the author's name; at the bottom, captions, buttons, a reply field. Together up to a fifth of the height in vertical formats.

In practice: keep the face and key elements in the central zone, leaving the edges to the interface. Always check the result inside the app rather than in an editor.

Duration

Formats set not only a maximum but an optimum. The maximum allowed length is usually far beyond what is actually watched through.

For short vertical formats the optimum is the opening seconds: if movement has not begun immediately, the clip is scrolled past regardless of what follows.

File size and bitrate

Size limits rarely trouble short generated clips — they are markedly lighter than ordinary footage. If a limit is exceeded, compress once and as gently as possible.

The first frame as a thumbnail

Many platforms take the clip's first frame as a static thumbnail. If the clip opens on a dark frame or mid-movement, the thumbnail will be poor.

In practice: make the first frame a self-sufficient image. Some platforms let you choose a cover frame manually — worth using.

Muted autoplay

Standard behaviour nearly everywhere. The clip must be comprehensible without sound; if the content rests on audio, add subtitles or on-screen text.

For generated clips this is usually not a problem — they are silent anyway — but keep it in mind when adding music: most viewers will not hear it.

A pre-publication checklist

1. Does the format match the platform without cropping anything important?
2. Is the face clear of the zones covered by the interface?
3. Does the movement start within the first second?
4. Does the first frame work as a thumbnail?
5. Is the clip comprehensible without sound?
6. Is the file uploaded at original quality, without extra compression?