Protecting elementary stream content
Protecting elementary stream media content is described. In one aspect, data segments within elementary stream media content are identified. Each data segment includes a single video or audio frame. Encryption boundaries for protecting the payload packets are selected to correspond to data segment boundaries. The elementary stream media content is then protected using the selected encryption boundaries.
1 . A computer-implemented method comprising:
identifying data segments of elementary stream content, each data segment comprising a single video or audio frame;
selecting encryption boundaries for protection of the elementary stream content, the encryption boundaries corresponding to the data segments; and
protecting the elementary stream content using the encryption boundaries.
2 . The method of claim 1 , wherein the elementary stream content is carried by a transport stream
3 . The method of claim 1 , wherein protecting further comprises encrypting respective ones of the data segments with Advanced Encryption Standard in Counter Mode.
4 . The method of claim 1 wherein protecting further comprises:
analyzing a transport stream to determine portions of the transport stream that are to pass unencrypted; and
wherein protecting further comprises preparing the transport stream for processing that bypasses commonly scrambled portions of the transport stream.
5 . The method of claim 1 , wherein an elementary stream of the elementary stream content comprises Media Access Units (MAUs), and wherein protecting further comprises:
for each MAU of the MAUs, applying a respective set of encryption parameters to each data segment of one or more data segments associated with the MAU, the respective encryption parameters either encrypting the data segment or leaving the data segment in the clear such that respective sets of encryption parameters apply to each separate data segment.
6 . The method of claim 5 , wherein each data segment is a contiguous section of the MAU.
7 . The method of claim 5 , wherein a portion of the MAU is left in the clear.
8 . The method of claim 5 , wherein the transport protocol is the Real-Time Transport Protocol (RTP).
9 . The method of claim 5 , further comprising mapping the MAUs to a MAU Payload Format for encapsulation into a transport protocol.
10 . The method of claim 9 , wherein the MAU Payload Format comprises packet specific information associated with each of the MAUs.
11 . The method of claim 9 , wherein the MAU Payload Format comprises a MAU properties section for describing a particular MAU of the MAUs; and
if the MAU is fragmented, the properties section including information to allow a receiver to parse the MAU when a fragmented portion of the MAU is lost.
12 . The method of claim 9 , wherein the MAU Payload Format comprises a MAU timing section to provide information about timestamps associated with a MAU of the MAUs.
13 . The method of claim 12 , wherein the information comprises a Normal Play Time (NPT) timeline associated with the MAU, the NPT for assisting specification, by a receiver, a position to seek to within a presentation.
14 . The method of claim 12 , wherein the information comprises a presentation time indicating when the receiver is to present content of the MAU.
15 . A computer-implemented method comprising:
receiving encrypted portions of an elementary stream (ES), the ES being represented with multiple Media Access Units (MAUs), each MAU corresponding to a single frame of video or audio of the ES, the ES being associated with information allowing the ES to be processed independent of any other ES, and each MAU being associated with information allowing the MAU to be processed independent of any other MAU; and
processing the ES or at least one MAU of the MAUs.
16 . The method of claim 15 , wherein the elementary stream is carried by a commonly scrambled transport stream.
17 . The method of claim 15 , wherein the ES is encapsulated by Real-Time Transport Protocol (RTP) packets.
18 . The method of claim 15 , wherein the elementary stream is carried by a transport stream, and wherein processing further comprises demultiplexing the transport stream to derive elementary streams.
19 . A computer-implemented method comprising:
identifying Media Access Units (MAUs) of elementary stream content;
for each MAU of the MAUs, the MAU comprising one or more data segments representing a single video or audio frame, selecting encryption boundaries based on the one or more data segments for protection of the single video or audio frame and associated headers; and
protecting the elementary stream content based on the encryption boundaries such that each data segment is associated with a respective set of encryption parameters that is independent of another data segment's corresponding encryption parameters.
20 . The method of claim 19 , wherein the elementary stream content is carried by a transport stream, and wherein protecting further comprises commonly scrambling the transport stream to prepare the transport stream for processing that bypasses encrypted content.