| 摘要 |
Digital content is extracted from single and multiple-program transport streams for subsequent non-real-time (background) transmission in a bandwidt h- efficient manner. At an encoder (100), several null and/or nonessential (N/N ) packets (e.g., packets of unused programs) in a transport stream are replace d by an annotation packet (AP) to obtain non-real-time packets (410). The non- real time packets are inserted into null packet locations (NU) of a real tim e transport stream. At a decoder (200), the annotation packets are used to regenerate a specified number of null packets to maintain the original separation of packets of the non-real time data (for timing purposes), allowing existing hardware and/or software to decode the selected program. Optionally, the non-real-time packets provide pre-encrypted programs, and decryption information is distributed to the decoders at a formal program release time specified by the program provider.
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