Recognition of voice-activated commands

1. A method performed in a digital home communication terminal (DHCT), the method comprising:

storing a program audio signal corresponding to a program tuned by the DHCT, wherein the program audio signal is stored as a plurality of time-shifted versions of the program audio signal;

storing an incoming audio signal carrying speech;

removing from the incoming audio signal a portion of the incoming audio signal that corresponds to the program audio signal, thus producing an improved version of the incoming audio signal;

selecting one of a plurality of voice-activated commands that corresponds to the improved version of the incoming audio signal; and

performing a function corresponding to the selected voice-activated command.

2. The method of claim 1 , wherein the incoming audio signal is received from a remote control.

3. The method of claim 1 , further comprising:

confirming the selected one of the voice-activated commands with a user before performing the function.

4. The method of claim 1 , wherein the number of time-shifted versions is configurable.

5. The method of claim 1 , wherein the improved version of the incoming audio signal includes a plurality of candidate incoming audio signals, and the removing further comprises:

generating each of the candidate incoming audio signals by subtracting a respective one of the time-shifted versions of the program audio signal from the incoming audio signal;

and the selecting further comprises:

selecting the one of the voice-activated commands by comparing each of the candidate incoming audio signals to a dictionary of voice-activated commands.

6. A method performed in a digital home communication terminal (DHCT), the method comprising:

storing a program audio signal, corresponding to a program tuned by the DHCT, as samples in a program audio buffer;

receiving an incoming audio signal carrying speech;

storing the incoming audio signal as samples in an incoming audio buffer;

generating a plurality of candidate signals by subtracting, from the samples in the incoming audio buffer, a portion of samples in the incoming audio signal that corresponds to the samples stored in the program audio buffer;

determining a best match within a dictionary of voice-activated commands based on the candidate signals; and

performing a function corresponding to the best match voice-activated command.

7. The method of claim 6 , wherein the incoming audio signal is received from a remote control.

8. The method of claim 6 , further comprising:

confirming the determined one of the voice-activated commands with a user before performing the function.

9. The method of claim 6 , wherein the buffers are implemented as circular buffers.

10. The method of claim 6 , wherein the program audio buffer includes a plurality of time-shifted portions, each time-shifted portion storing a different time-shifted version of the program audio signal, wherein the generating further comprises:

generating each of the candidate signals by subtracting the samples in a respective one of the time-shifted portions of the buffer from the samples in the incoming audio buffer.

11. The method of claim 10 , wherein at least some of the time-shifted portions overlap.

12. The method of claim 10 , wherein the number of time-shifted versions is configurable.

13. A method performed in a digital home communication terminal (DHCT), the method comprising:

demultiplexing a received transport stream into a compressed audio stream and a control stream;

decoding the compressed audio stream;

storing audio corresponding to a tuned program;

storing a start and length of a no-active-speech command, wherein the skipping utilizes the start and the length;

separating the stored audio from the compressed audio stream by subtracting the stored audio from the decoded audio stream, until the no-active-speech command is found in the control stream; and

responsive to the no-active-speech command, skipping the subtracting for a period corresponding to a duration of the no-active-speech command.

14. The method of claim 13 , further comprising:

receiving the control stream from a remote control.

15. The method of claim 13 , wherein the decoding begins upon finding a start command in the control stream.

16. The method of claim 13 , wherein the decoding ends upon finding a stop command in the control stream.

17. The method of claim 13 , the separating further comprising subtracting samples of the stored audio from a program buffer from the samples of the decoded audio stream from a speech buffer, the method further comprising:

responsive to the no-active-speech command, advancing a consumer index in the program buffer by an amount corresponding to a duration of the no-active-speech command.