The status of the reading of sample buffers from the asset.
- iOS 4.1+
- macOS 10.7+
- Mac Catalyst 13.0+Beta
- tvOS 9.0+
This property is thread safe. For possible values, see
The value of this property indicates whether reading is in progress, has completed successfully, has been canceled, or has failed. You should check the value of this property after the
NULL to determine why no more samples could be read.