Compact signal coding method and apparatus
View Patent ↗A compact signal coding method and apparatus including obtaining cumulative probabilities for successive quantized samples of a signal, determine the direct probability for the leading one of the successive quantized samples, and encode the quantized sample based at least in part on the determined direct probability.
1. A computer-implemented method of encoding data, the method comprising:
obtaining, in a computer, a first cumulative probability for a quantized sample of a signal to be greater than or equal to a quantized sample x i of the signal;
obtaining a second cumulative probability for a quantized sample of the signal to be greater than or equal to a quantized sample x i +1;
computing a direct probability for the quantized sample x i of the signal, using the obtained first and second cumulative probabilities; and
encoding the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal to produce a decodable representation of the data.
2. The method of claim 1 , wherein at least one of said obtaining is based at least in part on a selected one from a group consisting of a known cumulative probability distribution for the signal, and an estimated cumulative probability distribution for the signal.
3. The method of claim 1 , wherein the obtaining of the first cumulative probability comprises obtaining the first cumulative probability by sub-sampling a cumulative probability distribution for a quantized sample of the signal being greater than or equal to x i , when the signal is quantized with a first quantization step size, the cumulative probability being nested monotonic.
4. The method of claim 1 , wherein the obtaining comprises retrieving the first cumulative probability from a table having a cumulative probability for a quantized sample of the signal to be greater than or equal to x i , when the signal is quantized with a first quantization step size, the cumulative probability being nested monotonic.
5. The method of claim 4 , wherein the method further comprises receiving the first quantization step size.
6. The method of claim 1 , wherein the computing comprises computing a difference between the obtained first and second cumulative probabilities.
7. The method of claim 1 , wherein the encoding comprises generating a prefix code for the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal.
8. method of claim 7 , wherein the generating is further based on the first cumulative probability.
9. The method of claim 8 , wherein the generating comprises selecting a number of most significant bits from a binary representation of the first cumulative probability, the number being dependent on the determined direct probability.
10. The method of claim 9 , wherein the generating comprises selecting a number of most significant bits from a binary representation of a difference between the first cumulative probability and the determined direct probability, the number being dependent on the determined direct probability.
11. The method of claim 1 , wherein the encoding comprises generating a Shannon code for the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal.
12. The method of claim 1 , wherein the encoding comprises generating a Gilbert-Moore code for the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal.
13. The method of claim 1 , wherein the method further comprises selecting the quantized sample x i of the signal.
14. The method of claim 13 , wherein the method further comprises receiving a plurality of quantized samples of the signal, and the quantized sample x i of the signal is selected from the received plurality of quantized samples of the signal.
15. The method of claim 14 , wherein the method further comprises repeating the selecting, the two obtaining, the computing and the generating for another quantized sample x i of the signal selected from the received plurality of quantized samples of the signal.
16. The method of claim 1 , wherein the signal is selected from the group consisting of a video signal, an image signal, and an audio signal.
17. An encoder to encode data, the encoder comprising:
a storage medium having stored therein a plurality of programming instructions, which when executed enable the encoder to:
obtain a first cumulative probability for a quantized sample of a signal to be greater than or equal to a quantized sample x i of the signal,
obtain a second cumulative probability for a quantized sample of the signal to be greater than or equal to a quantized sample x i +1,
compute a direct probability for the quantized sample x i of the signal, using the obtained first and second cumulative probabilities, and
encode the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal to produce a decodable representation of the data; and
at least one processor coupled to the storage medium to execute the plurality of programming instructions.
18. The encoder of claim 17 , wherein at least one of said obtainings of a cumulative probability for a quantized sample of the signal is based at least in part on a selected one from the group consisting of a known cumulative probability distribution of the signal, and an estimated probability distribution of the signal.
19. The encoder of claim 17 , wherein the storage medium further comprises a table having a cumulative probability for a quantized sample x i of the signal to be greater than or equal to x i , when the signal is quantized with a first quantization step size, the cumulative probability being nested monotonic.
20. The encoder of claim 17 , wherein the plurality of programming instructions are operative to perform the computing by computing a difference between the obtained first and second cumulative probabilities.
21. The encoder of claim 17 , wherein the plurality of programming instructions are operative to perform the encoding by generating a prefix code for the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal.
22. The encoder of claim 17 , wherein the plurality of programming instructions are operative to perform the encoding by generating a Shannon code for the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal.
23. The encoder of claim 17 , wherein the plurality of programming instructions are operative to perform the encoding by generating a Gilbert-Moore code for the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal.
24. An encoder, coupled to a system, to encode data, the encoder comprising:
means for obtaining a first cumulative probability for a quantized sample of a signal to be greater than or equal to a quantized sample x i of the signal;
means for obtaining a second cumulative probability for a quantized sample of the signal to be greater than or equal to a quantized sample x i +1;
means for computing a direct probability for the quantized sample x i of the signal, using the obtained first and second cumulative probabilities; and
means for encoding the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal to produce a decodable representation of the data.
25. The encoder of claim 24 , wherein at least one of said means for obtaining is operative to perform the obtaining based at least in part on a selected one from the group consisting of a known cumulative probability distribution of the signal, and an estimated cumulative probability distribution of the signal.
26. The encoder of claim 24 , wherein the encoder further comprises means for storing a table having a cumulative probability for a quantized sample of the signal to be greater than or equal to x i , when the signal is quantized with a first quantization step size, the cumulative probability being nested monotonic.
27. A decoder, coupled to a system, to decode encoded data, the decoder comprising:
means for receiving an encoded quantized sample x i of a signal;
means for decoding the encoded quantized sample x i of the signal by performing an inverse operation on the encoded quantized sample x i of the signal, based at least in part on a direct probability for the encoded quantized sample x i of the signal; and
means for rendering the decoded sample.
28. The decoder of claim 27 , wherein the decoder is further operative to perform the inverse operation based on a cumulative probability for a quantized sample of the signal to be greater than or equal to the quantized sample x i of the signal.
29. The decoder of claim 27 , wherein the decoder is further operative to perform the inverse operation based on the encoded quantized sample x i of the signal having been Shannon code generated, based at least in part on the computed direct probability for the quantized sample x i of the signal.
30. The encoder of claim 27 , wherein the decoder is further operative to perform the inverse operation based on the encoded quantized sample x i of the signal having been Gilbert-Moore code generated, based at least in part on the computed direct probability for the quantized sample x i of the signal.
31. The decoder of claim 27 , wherein the decoder further comprises means for storing a table having a cumulative probability for a quantized sample of the signal to be greater than or equal to x i , when the signal is quantized with a first quantization step size, the cumulative probability being nested monotonic.
32. A system comprising:
an encoder operative to:
obtain a first cumulative probability for a quantized sample of a signal to be greater than or equal to a quantized sample x i of the signal,
obtain a second cumulative probability for a quantized sample of the signal to be greater than or equal to a quantized sample x i +1,
compute a direct probability for the quantized sample x i of the signal, using the obtained first and second cumulative probabilities, and
encode the quantized sample x i of the signal, based at least in part on the computed direct probability for the quantized sample x i of the signal to produce a decodable representation of the data; and
a transmitter coupled to the encoder to transmit the decodable representation of the data.
33. The system of claim 32 , wherein at least one of said obtainings of a cumulative probability for a quantized signal is based at least in part on a selected one from the group consisting of a known cumulative probability distribution of the signal, and an estimated cumulative probability distribution of the signal.
34. The system of claim 32 , wherein the encoder further stores a table having a cumulative probability for a quantized sample of the signal to be greater than or equal to x i , when the signal is quantized with a first quantization step size, the cumulative probability being nested monotonic.
35. The system of claim 32 , wherein the system is selected from the group consisting of a palm sized computing device, a wireless mobile phone, a digital personal assistant, a set-top box, a digital versatile disk player, a television, and a display monitor.
36. A system comprising:
a receiver operative to receive an encoded quantized sample x i of a signal;
a decoder coupled to the receiver and operative to decode the received encoded quantized sample x i of the signal by performing an inverse operation on the encoded quantized sample x i of the signal, based at least in part on a direct probability for the quantized sample x i of the signal; and
a renderer coupled to the decoder to render the decoded quantized sample x i of the signal.
37. The system of claim 36 , wherein the encoder is further operative to store a table having a cumulative probability for a quantized sample of the signal to be greater than or equal to x i , when the signal is quantized with a first quantization step size, the cumulative probability being nested monotonic.
38. The system of claim 36 , wherein the system is selected from the group consisting of a palm sized computing device, a wireless mobile phone, a digital personal assistant, a set-top box, a digital versatile disk player, a television, and a display monitor.