Method of identifying multiple digital streams within a multiplexed signal
View Patent ↗In a subscriber television system with a host terminal, the present invention allows the identification of the individual packets from two separate MPEG transport streams that have been multiplexed together for decoding by a single external conditional access or point-of-deployment (POD) module. The decoding of individual packets from two separate MPEG transport streams supports the use of multiple tuner host terminals for such functions as picture-in-picture (PIP) program viewing and the viewing of one program while recording a second program.
1. A system comprising:
a processor configured to assign a unique designator to a source device of a packetized data stream, wherein the unique designator identifies the source device and allows a decryptor to determine decryption parameters based on the identification of the source device wherein the processor is further configured to create a unique designator signal that includes the unique designator;
a multiplexer configured to multiplex a portion of the packetized data stream with a second packetized data stream to create a multiplexed signal; and
a transmitter configured to transmit the unique designator in conjunction with the multiplexed signal wherein the transmitter is further configured to transmit the unique designator signal in conjunction with the multiplexed signal, wherein the unique designator signal provides the unique designator at the start of a byte of the packetized data stream.
2. The system of claim 1 , wherein the packetized data stream is in a format compliant with one of Moving Picture Experts Group type 2 (MPEG-2) standard, Moving Picture Experts Group type 4 (MPEG-4) standard, Asynchronous Transfer Modulation (ATM) standard, and Internet Protocol (IP) standard.
3. The system of claim 1 , wherein the processor is further configured to encrypt the multiplexed signal before it is transmitted.
4. The system of claim 1 , further comprising an encryptor configured to encrypt the multiplexed signal.
5. A method comprising:
receiving, at a terminal, a signal, the signal including a unique designator indicating the source device of at least a portion of the signal wherein receiving the signal comprises receiving a unique designator signal in conjunction with the signal, wherein the unique designator signal provides the unique designator at the start of at least one packet of the signal;
demultiplexing at least the portion of the signal; identifying the source device of the portion of the signal from the unique designator; and
determining decryption parameters based on the identification of the source device.
6. The method of claim 5 , wherein the signal is in a format compliant with one of Moving Picture Experts Group type 2 (h4PEG-2) standard, Moving Picture Experts Group type 4 (MPEG-4) standard, Asynchronous Transfer Modulation (ATM) standard, and Internet Protocol (IP) standard.
7. The method of claim 5 , wherein the signal is received in an external conditional access module configured to decrypt the at least one packet of the signal based on the source device of the signal indicated by the unique designator.
8. The method of claim 5 , further comprising decrypting the received signal.
9. The method of claim 5 , wherein the signal is received from a host terminal.
10. A method of decryption comprising:
receiving an RF signal in a first tuner; assigning to the first tuner, a first address;
producing from the first tuner, a first output signal comprising a first encrypted signal;
transmitting to a point-of-deployment (POD) module, the first encrypted signal together with the first address;
determining decryption parameters based on the first address;
receiving the RF signal in a second tuner;
assigning to the second tuner, a second address;
producing from the second tuner a second output signal comprising a second encrypted signal;
transmitting to the POD module, the second encrypted signal together with the second address;
providing a second authorization information to the POD module;
identifying the second encrypted signal using the second address; and
decrypting the second encrypted signal conditional to a second grant of authorization contained in the second authorization information.
11. The method of claim 10 , further comprising: providing a first authorization information to the POD module; and identifying the first encrypted signal using the first address.
12. The method of claim 11 , further comprising: decrypting the first encrypted signal conditional to a first grant of authorization contained in the first authorization information.
13. The method of claim 10 , further comprising: generating a multiplexed signal by multiplexing the first and second encrypted signals together with the first and second addresses; transmitting the multiplexed signal to the POD module; and demultiplexing the multiplexed signal in the POD module.
14. The method of claim 13 , further comprising: providing at least one of the first and second authorization information through an out-of-band signal contained in the RF signal.