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Creates random access data (Blob) from an MSStream object.


Indicates that the read has been aborted (for example, by calling abort()).


Performs an asynchronous read of an MSStream object in order to create a Blob object.
Returns partial Blob data representing the number of bytes currently loaded (as a fraction of the total), decoded into memory according to the encoding determination.


No events.


MSStreamReader is a constructor function producing an object that provides methods to asynchronously read an MSStream, and an event model to obtain the results of these reads. MSStreamReader lets you read and interact with MSStream objects. MSStreamReader performs the conversion of multimedia that is in a C++ file format into a format that can be accessed by JavaScript. The original file is accessed as an MSStream that overlays a Blob object. MSStreamReader uses the readAsBlob method to perform an asynchronous read of data from the MSStream when converting it to a Blob. A series of events is used to track the progress of the read and any errors that occur. The MSStreamReader can be in one of three states. The readyState returns the current state. The state is one of the following values:

  • EMPTY. The MSStreamReader object has been created and there are no pending reads. This is the default state of a new MSStreamReader object until the readAsBlob method is called.
  • LOADING. An MSStream is being read. The readAsBlob method is running and no error has occurred during the read.
  • DONE. The entire MSStream has been read into memory, a file error occurred during the read, or the read was aborted using the abort method. The MSStreamReader is no longer reading an MSStream. If readyState is set to DONE, it means that the readAsBlob method has been called at least once.

When the MSStreamReader read operation is done on the MSStream, the result property returns the Blob object that contains the data buffered from the MSStream. The result is returned after the onloadend event has fired.