System and method for efficient support for short cryptoperiods in template mode

摘要

System and method embodiments are provided herein for efficient representation and use of initialization vectors (IVs) for encrypted segments using template mode representation in Dynamic Adaptive Streaming over Hypertext Transfer Protocol (DASH). An embodiment method includes sending in a media presentation description (MPD), from a network server to a client, a template for generating a universal resource locator (URL) to obtain an IV that is used for encrypting a segment, in absence of an IV value in the MPD, receiving from the client a URL configured according to the template, and upon receiving the URL, returning an IV corresponding to the URL to the client. Another embodiment method includes receiving in a MPD, at a client from a network server, a template for generating a URL to obtain an IV that is used for encrypting a segment, upon detecting an absence of an IV value or IV base value in the MPD, configuring a URL for the IV using the template, sending the URL for the IV, and receiving an IV.

主权项

1. A method for communicating encryption information in template mode in dynamic adaptive streaming over hypertext transfer protocol (DASH), the method comprising:
sending in a media presentation description (MPD), from a network server to a client, a template for generating a universal resource locator (URL) to obtain an initialization vector (IV) that is used for encrypting a segment, wherein the segment is associated with a cryptoperiod where a plurality of segments are encrypted with the same encryption parameters; including, in the MPD, a CryptoTimeline element for deriving one or more cryptoperiods at the client using run-length coding, the CryptoTimeline element indicating a sequence of cryptoperiods of constant duration each including the same number of segments, wherein the CryptoTimeline element includes a first optional attribute for indicating a number of constant-duration cryptoperiods within a timeline, a second mandatory attribute for indicating, by a number of segments, a cryptoperiod duration of every period in the timeline, and a third optional attribute for indicating a number of segments between the end of a previous CryptoTimeline element and the timeline; in absence of an IV value in the MPD, receiving from the client a URL for the IV configured according to the IV URL template associated with at least one of the one or more cryptoperiods within the timeline; and upon receiving the IV URL, returning an IV value corresponding to the IV URL to the client for decrypting each of the plurality of segments associated with the at least one cryptoperiod.