APPARATUSES AND METHODS FOR PARAMETER SELECTION DURING RATE-DISTORTION OPTIMIZATION
Apparatuses and methods for parameter selection are disclosed. An example apparatus may include an encoder configured to receive a coding unit and to provide coefficients based on the coding unit. The encoder may further be configured to quantize the coefficients using a first quantization parameter to provide a first set of quantized coefficients and to quantize the coefficients using a second quantization parameter to provide a second set of quantized coefficients. The encoder may further be configured to provide a first rate-distortion pair based on the first set of quantized coefficients and to provide a second rate-distortion pair based on the second set of quantized coefficients. The encoder may further be configured to provide a rate-distortion curve based on the first and second rate-distortion pairs and to provide a Lagrangian parameter based on the rate-distortion curve. The encoder may be configured to encode the coding unit using the Lagrangian parameter.
1 . An apparatus, comprising:
an encoder configured to receive a coding unit and to provide coefficients based on the coding unit, the encoder further configured to quantize the coefficients using a first quantization parameter to provide a first set of quantized coefficients and to quantize the coefficients using a second quantization parameter to provide a second set of quantized coefficients, the encoder further configured to provide a first rate-distortion pair based on the first set of quantized coefficients and to provide a second rate-distortion pair based on the second set of quantized coefficients, the encoder further configured to provide a rate-distortion curve based on the first and second rate-distortion pairs and to provide a Lagrangian parameter based on the rate-distortion curve;
wherein the encoder is further configured to encode the coding unit using the Lagrangian parameter.
2 . The apparatus of claim 1 , wherein the Lagrangian parameter is a first Lagrangian parameter, and wherein the encoder is further configured to optimize the first set of quantized coefficients using a second Lagrangian parameter.
3 . The apparatus of claim 1 , wherein the Lagrangian parameter is based on a slope of the rate-distortion curve.
4 . The apparatus of claim 3 , wherein the Lagrangian parameter is based on an absolute value of the slope of the rate-distortion curve.
5 . The apparatus of claim 1 , wherein the first quantization parameter is specified by a mode decision.
6 . The apparatus of claim 1 , wherein the encoder is configured to quantize coefficients associated with the coding unit using the Lagrangian parameter.
7 . The apparatus of claim 1 , wherein the encoder is further configured to provide the rate-distortion curve using linear regression, polynomial curve fitting, or combinations thereof.
8 . An encoder, comprising:
a parameter selection block configured to provide a plurality of rate-distortion pairs based on a set of coefficients, each of the rate-distortion pairs indicative of a rate and a distortion for encoding the set of coefficients with a respective quantization parameter, the parameter selection block further configured to provide a Lagrangian parameter based on the plurality of rate-distortion pairs; and
a quantization block coupled to the parameter selection block and configured to receive the Lagrangian parameter, the quantization block configured to quantize the set of coefficients based on the Lagrangian parameter.
9 . The encoder of claim 8 , wherein the parameter selection block is further configured to quantize the set of coefficients using each of the plurality of quantization parameters.
10 . The encoder of claim 9 , wherein the parameter selection block is configured to provide a rate-distortion curve based on each of the plurality of rate-distortion pairs.
11 . The encoder of claim 8 , further comprising:
a mode decision block configured to provide the plurality of quantization parameters.
12 . The encoder of claim 8 , wherein the Lagrangian parameter is based on a slope of a rate-distortion curve, the rate-distortion curve based on the plurality of rate-distortion pairs.
13 . The encoder of claim 12 , wherein the rate-distortion curve is based on at least one of linear regression or polynomial curve fitting.
14 . A method, comprising:
providing, using an encoder, coefficients of a coding unit of a video signal;
performing a plurality of encodes of the coefficients to provide a plurality of rate-distortion pairs, each of the encodes performed using a respective quantization parameter;
providing a rate-distortion curve based on the plurality of rate-distortion pairs; and
providing a Lagrangian parameter, the Lagrangian parameter corresponding to a slope of the rate-distortion curve.
15 . The method of claim 14 , wherein performing a plurality of encodes of the coefficients to provide a plurality of rate-distortion pairs comprises:
optimizing quantized coefficients, the quantized coefficients based on the coefficients.
16 . The method of claim 15 , wherein optimizing quantized coefficients comprises:
optimizing the quantized coefficients based on a plurality of Lagrangian parameters.
17 . The method of claim 15 , wherein optimizing quantized coefficients comprises:
optimizing the quantized coefficients using dynamic programming.
18 . The method of claim 14 , wherein providing a rate-distortion curve based on the plurality of rate-distortion pairs comprises:
providing a rate-distortion curve based on the plurality of rate-distortion pairs using linear regression, polynomial curve fitting, or combinations thereof.
19 . The method of claim 18 , providing a Lagrangian parameter comprises:
determining an absolute value of the slope of the rate-distortion curve.
20 . The method of claim 14 , further comprising:
quantizing the coding unit based on the Lagrangian parameter.
21 . The method of claim 14 , further comprising:
determining, using a mode decision block, a mode for encoding the coding unit based on the Lagrangian parameter.