Method and system for rate control in a video encoder
Presented herein are systems, methods, and apparatus for real-time high definition television encoding. In one embodiment, there is a method for encoding video data. The method comprises estimating amounts of data for encoding a plurality of pictures in parallel; generating a plurality of target rates corresponding to the plurality of pictures based on the estimated amounts of data for encoding the plurality of pictures; and lossy compressing the plurality of pictures based on the target rates corresponding to the plurality of pictures.
1 . A method for encoding video data, said method comprising:
classifying a set of pictures on a block-by-block basis;
generating a set of quantization maps for the set of pictures; and
encoding the set of pictures based on the set of quantization maps.
2 . The method of claim 1 , wherein classifying the set of pictures is a parallel process.
3 . The method of claim 1 , wherein encoding the set of pictures is a parallel process.
4 . The method of claim 1 , wherein classifying further comprises:
measuring a persistence of a portion of a picture in the set of pictures.
5 . The method of claim 4 , wherein a quantization map that corresponds to the picture comprises a relative quantization parameter that corresponds to the portion, and wherein a finer quantization is indicated when the persistence is relatively long.
6 . The method of claim 1 , wherein classifying further comprises:
measuring an intensity of a portion of a picture in the set of pictures.
7 . The method of claim 6 , wherein a quantization map that corresponds to the picture comprises a relative quantization parameter that corresponds to the portion and wherein the relative quantization parameter indicates a finer quantization when the intensity is relatively low.
8 . The method of claim 1 , wherein classifying further comprises:
generating a detection metric based on a statistical probability that a portion of a picture in the set of pictures contains an object with a perceptual quality.
9 . The method of claim 8 , wherein a quantization map that corresponds to the picture comprises a relative quantization parameter that corresponds to the portion and wherein the relative quantization parameter indicates a finer quantization when the perceptual quality of the object is important to a viewer of the picture.
10 . The method of claim 8 , wherein a quantization map that corresponds to the picture comprises a relative quantization parameter that corresponds to the portion and wherein the relative quantization parameter indicates a coarser quantization when the perceptual quality of the object is unimportant to a viewer of the picture.
11 . The method of claim 8 , wherein a quantization map is updated based on a comparison of a feedback signal to the statistical probabilities.
12 . The method of claim 11 , wherein the quantization map adjusts a nominal quantization parameter which is adjusted to obtain a desired rate profile.
13 . A system for encoding video data, said system comprising:
a master; and
a plurality of encoders, wherein each encoder comprises:
a classification engine for classifying a picture on a block-by-block basis;
a quantization map for storing a set of relative quantization parameters according to the classification;
a quantizer for lossy compressing the picture, wherein a quantization is controlled by the master and based on the quantization maps from other encoders.
14 . The system of claim 13 , wherein each encoder further comprises:
an intensity calculator for measuring an intensity of a portion of the picture, wherein a relative quantization parameter in the quantization map indicates a finer quantization when the intensity is relatively low.
15 . The system of claim 13 , wherein each encoder further comprises:
a persistence generator for measuring a persistence of a portion of the picture, wherein a relative quantization parameter in the quantization map indicates a finer quantization when the persistence is relatively long.
16 . The system of claim 13 , wherein each encoder further comprises:
a block detector for generating a detection metric based on a portion of the picture, wherein a relative quantization parameter in the quantization map indicates a finer quantization when an object of perceptual significance is detected according to the detection metric.
17 . The system of claim 15 , wherein the relative quantization parameter in the quantization map indicates a coarser quantization when an object of perceptual insignificance is detected according to the detection metric.
18 . The system of claim 13 , wherein the quantization map adjusts a nominal quantization parameter which is adjusted to obtain a desired rate profile.