[PDF] Roku Digital Video Player Getting Started
I found this when researching Trick Play and how they do Fast Foward and Rewind over the Internet where the can't just scan for I Frames on a local disk they way most traditional STB's achieve this.
Instead they use a BIF file. (Base Index Frame), that contains still images such as JPEG's ever 10 seconds or so and they play though those to give the illusion of a fast forward.
3.3 Trick Mode Support
Two types of trick mode support (FF/REW/SEEK) are provided. For developers who generate and publish image archives in Roku’s BIF (Base Index Frame) file format, scene based trick-mode using index frames will be supported. A specification is available which details the BIF file format and data required. If this data is published and available for a given title, scene based trick-modes will be available. The content meta-data indicates the availability of this data on a per title basis by providing URL’s for the HD and SD versions of these assets.
In cases where the BIF file is either not supported or unavailable, the system will present a time-based method of supporting trick modes. The user will be presented with a progress bar showing their location in the show and be allowed to seek using the normal trick play controls. Since scene information is not available, the user will only have a visual timeline and numeric time information to locate their desired position in the movie. Once the new location is selected, the system will buffer a minimal amount of stream data and begin playback.
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