Google publishes a codec list for Chromecast but it's buried in developer docs and doesn't tell you what to do when your file is MKV HEVC 10-bit. Here's the plain-English version, updated for 2026 — plus the LocalCast transcoding trick that makes "unsupported" a non-issue.
H.264 (Baseline, Main, High up to L4.2), HEVC / H.265 (Main / Main10 on 1st-gen Ultra and newer), VP9 (Profile 0 / 2), AV1 (Google TV Streamer and newer). Old Chromecast 1st gen stops at H.264.
LocalCast shows the codec of any file before you cast it. If Chromecast doesn't support it, you'll see an orange flag — no guessing.
Toggle on-device transcoding in Settings. LocalCast re-encodes the stream in real time to a format Chromecast understands. Only the first few seconds lag.
From there on, casting works exactly like a natively-supported file. Play, pause, seek, queue — all standard. The transcoder is automatic.
Yes, as a container — but only if the codecs inside are also supported. A MKV with H.264 video and AAC audio plays natively. A MKV with HEVC 10-bit video and DTS audio usually won't, unless your Chromecast model supports HEVC and you're running LocalCast, which handles DTS via on-device transcoding.
LocalCast transcodes whatever Chromecast can't handle. Free forever.