Open the inspector for the actual file
In QuickTime Player, open the media file and choose Window, Show Movie Inspector, or press Command-I. Apple documents video information including HDR format, aspect ratio, compression, bit depth, size and frame rate, plus audio-format and data-rate information where available.
Record the fields actually shown for that file rather than filling absent values from the filename or a poster. A label containing 4K or HDR can be a personal name; the inspector provides a different kind of evidence. Keep its result attached to the exact source or export version inspected.
Use window controls for a different question
Apple separately documents Actual Size and Fit to Screen. The former uses the source size; the latter scales the movie to the screen. A larger playback window therefore does not, by itself, increase the encoded dimensions or establish that the source contains more detail.
In full-screen presentation, Fill Screen can scale and crop, while Panoramic changes the outer horizontal presentation to avoid cropping. These are view choices, not evidence that the original file was re-encoded. If an edge disappears only with one view choice, record that presentation state before assuming the source is missing pixels.
Build a reference that another person can compare
Save the file identity, relevant inspector values and the view mode used for the observation. If comparing two exports, inspect both separately. Similar duration and a shared image do not establish identical codecs, dimensions or audio tracks.
For a target device, compare the recorded properties with its complete container/video/audio requirements. Inspector data helps identify the candidate file; it is not a performed compatibility test or proof that every frame is intact. A known opening can still be followed by a later problem that requires its own playback observation.
Keep output-display claims outside the file report
The monitor’s current resolution, HDR state and audio destination are additional observations. A file described as HDR can be presented through a different output path, and its inspector label does not certify what an external screen is actually receiving.
No file or Mac display was tested for this article. It explains Apple’s documented metadata and view controls, allowing a support note to distinguish encoded properties from window scaling and the separate display chain.
Sources and scope
Scope notes distinguish published documentation, supplied information and editorial methods. They do not report a hands-on service test.
- Apple: MovieInspector properties — Officialcurrentindexedfields and WindowShowMovieInspector/CommandI; no fileinspectionperformed.
- Apple: QuickTime view modes — OfficialindexedActualSize/Fit/Fill/Panoramic definitions; display/rendering controls notencodedfileconversion.
