Expedited digital signal decoding
View Patent ↗Expedited digital signal decoding. A multicast or unicast data stream is sent from a headend to a set-top box at a natural rate. A decoder buffer in the set-top box begins to fill. Once the buffer is partially full, a decoder begins to decode the data at a rate lower than the natural rate. Images are displayed to the user before the buffer is full, allowing for a faster channel change.
1. A method for buffering Moving Picture Exert Group (MPEG) digital signals of at least a unicast or a multicast data streams in a home communication terminal, the method comprising the steps of:
reading data into a decoder buffer at a first data rate;
obtaining a first occupancy level in said decoder buffer, wherein said first occupancy level is a level at which the decoder buffer reaches a key frame of MPEG;
responsive to determining that the data in the decoder buffer includes the key frame and responsive to obtaining the first occupancy level, outputting data from said decoder buffer at a second data rate, wherein said second data rate is less than said first data rate, and displaying images on a display using data output at said second rate;
obtaining a second occupancy level in said decoder buffer; and
responsive to obtaining the second occupancy level, outputting data from said decoder buffer at a third data rate, wherein said third data rate is greater than said second data rate, and displaying images on the display using data output at the third data rate;
wherein a channel alternation occurs as a result of said home communication terminal outputting said digital signals from said decoder buffer prior to said decoder buffer reaching said second occupancy level at said second data rate.
2. The method of claim 1 , wherein said third data rate is equal to said first data rate.
3. The method of claim 1 , wherein said first data rate is a data rate at which a data stream comprising the data is sent.
4. The method of claim 1 , wherein said step of obtaining said second occupancy level comprises allowing said decoder buffer to fill.
5. The method of claim 1 , wherein said step of obtaining said second occupancy level comprises obtaining a full decoder buffer.
6. The method of claim 1 , further comprising tuning a home communications terminal to a multicast data stream and reading from said multicast data stream.
7. The method of claim 1 , further comprising reading the key frame into said decoder buffer prior to outputting data from said decoder buffer at said second data rate.
8. The method of claim 1 , further comprising tuning the home communications terminal to a unicast data stream and reading from said unicast data stream.
9. The method of claim 8 , further comprising closing said unicast data stream upon reaching a second third occupancy level of said decoder buffer and tuning to a multicast data stream to be read into said decoder buffer.
10. A method for buffering Moving Picture Exert Group (MPEG) digital signals of at least a unicast or a multicast data stream in a home communication terminal, the method comprising the steps of:
tuning to said unicast data stream;
reading said unicast data stream into a buffer wherein said first occupancy level is a level at which the buffer reaches a key frame of MPEG;
responsive to determining that the buffer includes a key frame and to obtaining the first occupancy level, outputting data from said buffer at a second data rate, wherein said second data rate is less than said first data rate, and displaying images on a display using data output at said second rate;
obtaining a second occupancy level in said buffer, wherein said second occupancy level is greater than said first occupancy level;
responsive to obtaining the second occupancy level, closing said unicast data stream;
tuning to said multicast data stream;
reading said multicast data stream into said buffer;
obtaining a third occupancy level in said buffer, wherein said third occupancy level is greater than said second occupancy level; and
responsive to obtaining the third occupancy level, outputting data from said buffer at a third data rate, wherein said third data rate is greater than said second data rate, and displaying images on the display using data output at the third data rate;
wherein a channel alternation occurs as a result of said home communication terminal outputting said digital signals from said decoder buffer prior to said decoder buffer reaching said second occupancy level at said second data rate.
11. The method of claim 10 , wherein said third data rate is equal to said first data rate.
12. The method of claim 10 , wherein said first data rate is a data rate at which a data stream comprising the data is sent.
13. The method of claim 10 , wherein a channel alteration occurs prior to said buffer being full.
14. The method of claim 10 , further comprising reading the key frame into said buffer prior to outputting data from said buffer at said second data rate.
15. A decoder buffer apparatus facilitating fast channel change before the decoder buffer is full comprising receiving digital signals of at least a unicast or a multicast Moving Picture Exert Group (MPEG) data streams in a home communication terminal at a first data rate to obtain a first occupancy level that represents a partially full buffer, wherein said first occupancy level is a level at which the decoder buffer reaches a key frame of MPEG, for outputting said data at a second data rate which is less than said first data rate in response to the first occupancy level and in response to determining that the digital signals received at the first data rate include said key frame, and for obtaining a second occupancy level wherein said second occupancy level is greater than said first occupancy level in order to output said data for display at a third data rate that is greater than said second data rate; wherein a channel alternation occurs as a result of said home communication terminal outputting said digital signals from said decoder buffer prior to said decoder buffer reaching said second occupancy level at said second data rate.
16. The decoder buffer of claim 15 , wherein said third data rate is equal to said first data rate.
17. The decoder buffer of claim 15 , wherein said first data rate is a data rate at which a data stream comprising the digital signals is sent.
18. The decoder buffer of claim 15 , wherein said second occupancy level is a full buffer.
19. The decoder buffer of claim 15 , wherein channel alterations may occur a channel alteration occurs prior to said buffer being full.