Posting Video on X: Limits, Specs, Muted Feeds
X’s video rules read nothing like domestic platforms: duration is capped by account tier, the timeline preview crops your framing, and most viewers scroll on mute — the publishing strategy changes with the parameters.
The hard limits
Free accounts cap video at 140 seconds (2:20); Premium extends to hours. Single files top out at 512MB. These two numbers shape content form: under 140 seconds goes up directly; longer content either becomes a thread of posts (community convention) or gets compressed into the cap.
Duration triage matters more than compression settings: cut the content to target length first, then argue about quality — jamming overtime content in by crushing bitrate yields long-and-blurry, the worst of both.
Encoding and the framing safe area
H.264 + AAC is the reliable pairing: friendliest to the platform’s transcode chain. Start at 1080p 30fps (60fps works, but 30 is plenty in a feed) with 8-12Mbps source — leave margin for the recompress.
Aspect ratio is free (16:9 and 9:16 both post), but the timeline preview shows a fixed window: vertical video renders as a center strip with empty sides. Put key information and subtitles in the center safe area — design the framing for the preview window, not fullscreen.
Publishing for muted autoplay
X’s feed autoplays muted by default: three seconds without a visual hook — big captions, motion, a contrast beat — and the scroll continues. Subtitles must be burned in: in a muted feed, burned-in captions are the only information channel; external files and voices do not exist.
Pick a cover frame at an action peak or a text-information frame; give the track enough (AAC 128kbps+) because plenty of viewers wear headphones. Platform recompression applies as always — ample source bitrate is the universal defense.