✳ CODEC COMPATIBILITY
Facebook Reels H.264 / AVC in MKV (Matroska)
H.264 / AVC in MKV (Matroska) is not in facebook-reels's documented upload list. Convert before uploading.
Quality impact not documented · MKV not in Facebook Reels upload list.
H.264 inside MKV is supported by FFmpeg and most desktop players. Not listed.
Choose a compatible conversion →Matroska specification (verified 2026-09-18) · Facebook Video Format Help (verified 2026-09-18)
Frequently asked
Does Facebook Reels support H.264 / AVC in MKV (Matroska)?
H.264 / AVC in MKV (Matroska) is not in facebook-reels's documented upload list. Convert before uploading. Koldflux's compatibility engine reaches this verdict from sourced platform documentation.
Should I convert H.264 / AVC in MKV (Matroska) for Facebook Reels?
H264 inside MKV is not the recommended upload for facebook-reels; H264 inside MP4 is.
Will Facebook Reels re-encode my file?
MKV not in Facebook Reels upload list.