1. A method comprising: extracting one or more features corresponding to one or more objects from a file containing two or more codestreams for a selected viewport of a page of the file, including extracting at least one of the one or more features without decoding; predicting a next viewport of the page from a plurality of different viewports based on a relationship of the next viewport to the selected viewport within the page, the predicted next viewport including one or more predicted objects from the file; ranking document objects based on a task being performed by an application, the one or more extracted features, and an overlap of document objects with the selected viewport that is to be displayed; selecting a set of the document objects based on rank and at least one constraint for the selected viewport; ranking the one or more predicted objects based on the task being performed by the application, the one or more extracted features for the document objects, and a probability that document objects overlap two or more of a plurality of different potential next viewports; and selecting a second set of document objects based on the predicted next viewport of the page and the ranking of the one or more predicted objects without receiving a client request associated with the predicted next viewport.
1. A method comprising: extracting one or more features corresponding to one or more objects from a file containing two or more codestreams for a selected viewport of a page of the file, including extracting at least one of the one or more features without decoding; predicting a next viewport of the page from a plurality of different viewports based on a relationship of the next viewport to the selected viewport within the page, the predicted next viewport including one or more predicted objects from the file; ranking document objects based on a task being performed by an application, the one or more extracted features, and an overlap of document objects with the selected viewport that is to be displayed; selecting a set of the document objects based on rank and at least one constraint for the selected viewport; ranking the one or more predicted objects based on the task being performed by the application, the one or more extracted features for the document objects, and a probability that document objects overlap two or more of a plurality of different potential next viewports; and selecting a second set of document objects based on the predicted next viewport of the page and the ranking of the one or more predicted objects without receiving a client request associated with the predicted next viewport. 23. The method of claim 1 , wherein a first predicted object is selected for the second set before a second predicted object, the second predicted object having a higher ranking based on the ranking of the one or more predicted objects, when the first predicted object overlaps the predicted next viewport.