✳ CODEC COMPATIBILITY
Youtube Long AV1 in MP4
youtube-long accepts AV1 in MP4; not the default but a documented supported option.
Low quality risk · AV1 inside MP4 is on YouTube's supported list.
AV1 inside MP4 (with the av01 sample entry) is the modern open-codec upload pair. Modern codec.
ISO/IEC 14496-12 (ISO Base Media File Format) (verified 2026-09-18) · YouTube Supported File Formats (verified 2026-09-18)
Frequently asked
Does Youtube Long support AV1 in MP4?
youtube-long accepts AV1 in MP4; not the default but a documented supported option. Koldflux's compatibility engine reaches this verdict from sourced platform documentation.
Should I convert AV1 in MP4 for Youtube Long?
No conversion is required: this combination is already within Youtube Long's accepted profile.
Will Youtube Long re-encode my file?
AV1 inside MP4 is on YouTube's supported list.