✳ CODEC COMPATIBILITY
X (Twitter) H.265 / HEVC in MP4
H.265 / HEVC in MP4 is not in x's documented upload list. Convert before uploading.
Quality impact not documented · HEVC is not in X Media Studio list.
HEVC inside MP4 is supported by modern platforms; older phones may not play it back. Not listed.
Choose a compatible conversion →ISO/IEC 14496-12 (ISO Base Media File Format) (verified 2026-09-18) · X Media Studio Library (verified 2026-09-18)
Frequently asked
Does X (Twitter) support H.265 / HEVC in MP4?
H.265 / HEVC in MP4 is not in x's documented upload list. Convert before uploading. Koldflux's compatibility engine reaches this verdict from sourced platform documentation.
Should I convert H.265 / HEVC in MP4 for X (Twitter)?
H265 inside MP4 is not the recommended upload for x; H264 inside MP4 is.
Will X (Twitter) re-encode my file?
HEVC is not in X Media Studio list.