Method and apparatus for transferring a video stream between a host device and an electronic descrambling device

摘要

The present invention relates to video data transmission to a USB dongle. A method is proposed in which a video stream derived from a single generator having a creator ID from a host apparatus is transmitted from the host apparatus to an electronic descrambling apparatus for descrambling at least one stream. The host device includes a controller including a bulk pipe-out and a bulk pipe-in during transmission, the method comprising: defining a data chunk from a video stream for each creator; Forming an out-transfer chain; Out transmission chain includes a chain-out descriptor (oqTD) and a linked chain-out header (oqH), the first chain-out descriptor points to an out-of-description packet containing at least one producer ID, and the second and subsequent The chain-out descriptor points to a data chunk that is a data chunk of a particular constructor, and the final chain-out descriptor is configured to generate an interrupt; - forming a transmission chain; - wherein the transport chain comprises a plurality of chains of descriptors iqTD and a chain of linked iQHs, each chain of descriptors pointing to a descrambled chunk of data; Requesting the controller to process the chain; - modifying the description packet by an electronic descrambling device and identifying key data associated with at least one chunk; Using key data to descramble the data chunks; receiving through a bulk pipe in a chunk descrambled by the controller; And triggering an interrupt by receiving a final descrambled chunk.