Collect the actual media details
Use the player’s media information to record codec, resolution and frame rate for the failing source. Compare a known working item rather than assuming two videos are equivalent because both are labelled 4K.
Xiaomi’s current FAQ distinguishes its advertised H.264 and HEVC decoder limits and lists some older formats as unsupported. Apply that information to the exact third-generation model, not to every Xiaomi box or stick.
Keep hardware decoding and application support separate
The manufacturer’s decoder capability is one layer. The installed application’s input and playback path is another. A file working in one player does not establish identical support in a browser or a different television app.
Do not install a Windows codec package onto an Android/Google TV box. Use the device and application’s supported software route.
Use the symptom to narrow the check
| Observed result | Useful evidence |
|---|---|
| Sound but no picture | Video codec, profile and frame rate |
| One file works, another fails | Actual format differences |
| App cannot install | Platform/store requirements |
| Every item fails login | Account format rather than decoder limit |
Retain a bounded conclusion
A successful test establishes the exact source and player on that model. It does not prove every format at the same resolution works. Keep the model generation and application version with the result so the next comparison remains meaningful.