A media-capability result can report whether a described configuration is supported and may provide smoothness or power-efficiency information. It is a prediction or capability response for that query, not proof that a complete program has played successfully.
Keep the requested configuration and runtime environment with the result.
Read every part of the query
Codec, dimensions, rate and other fields can define the configuration being asked about. A result for one set of values should not be generalized to all media using the same codec family. Audio and encrypted-playback requirements can add separate questions.
The W3C Media Capabilities document is a working specification describing these interfaces. Its existence does not guarantee identical implementation across browsers or devices. Record the actual browser and version when using a capability result.
A positive support response does not inspect your specific file’s correctness, source availability or account entitlement. Those are different dependencies. The media can still fail for reasons outside the queried decoding configuration.
Compare prediction and observation
For an authorized developer test, retain the exact configuration object and result without private media URLs. Then play an appropriate known test source in the same environment. Record opening, sustained motion, sound and any exposed dropped-frame information.
If the prediction and playback differ, preserve both. Do not rewrite the report so that a positive response becomes a passed viewing test. A mismatch is useful evidence for implementation or source investigation.
| Result or check | What it concerns |
|---|---|
| Supported response | The queried configuration in this implementation |
| Smooth/power-efficient response | Reported capability characteristics |
| Successful playback | An observed source and runtime result |
| Service access | A separate source/account dependency |
Keep consumer claims narrow
One browser query does not establish universal device compatibility. Nor should it infer a measured battery saving from a power-efficiency response. Actual sustained tests need their own method and conditions.
For ordinary viewers, exact model and application support remain the most practical starting points. If a capability diagnostic is used by support, keep its output alongside the real symptom. That combination is more informative than either one alone.
- Record the complete queried media configuration.
- Keep browser/device/software identity.
- Retain the actual capability response.
- Compare with an authorized runtime source test.
- Report predictions and observations as separate evidence.
Useful answers
Does a positive capability response prove a movie played?
No. It describes the queried configuration and does not replace actual playback evidence.
Does a power-efficient response measure my battery life?
No. A battery claim needs an appropriate observed measurement under stated conditions.