摘要:
A spatial activity metric for characterizing an image is established, typically based one of the image variance, image gradient or DCT coefficients. The spatial activity metric is then reduced by the amount of the estimated noise in the image so that upon the spatial activity metric in connection with spatial masking, the likelihood of unmasked distortion caused by the presence of noise, such as film grain will be reduced. The effectiveness of such a spatial activity metric can be determined by determining similarity of the measures made by the spatial activity metric for regions in the image of similar texture and by determining the difference in the measures made by the spatial activity metric for regions of different texture in the image.
摘要:
A method and apparatus are provided for rate control accuracy in video encoding. The apparatus includes a video encoder for encoding image data in a single encoding pass using rate control. The rate control involves defining a quantization step size value and a rounding offset value and refining at least the rounding offset value. The image data is encoded responsive to the quantization step size value and the refined rounding offset value.
摘要:
There are provided methods and apparatus for improved quantization rounding offset adjustment for video encoding and decoding. An apparatus includes a video encoder for encoding an input coding unit by determining a residual for the input coding unit corresponding to a difference between the input coding unit and a reference coding unit, applying a transform to the residual to obtain at least one transform coefficient, and quantizing the at least one transform coefficient by selecting a particular quantization step size and a rounding offset.
摘要:
There are provided methods and apparatus for improved quantization rounding offset adjustment for video encoding and decoding. An apparatus includes a video encoder for encoding an input coding unit by determining a residual for the input coding unit corresponding to a difference between the input coding unit and a reference coding unit, applying a transform to the residual to obtain at least one transform coefficient, and quantizing the at least one transform coefficient by selecting a particular quantization step size and a rounding offset.
摘要:
Methods and apparatus are provided for rate control accuracy in video encoding and decoding. An apparatus includes a video encoder for encoding image data using rate control. The rate control involves estimating a quantization step size and adjusting a rounding offset. The rounding offset is capable of being non-constant during the encoding.
摘要:
The present principles provides a method and apparatus for jointly adjusting the rounding offset and the quantization step size on a macroblock level to improve the perceptual quality of the fine details of the encoded image. In one implementation, the content of the pictures is analyzed and the smooth regions are identified. A quantization step size value for the picture is initially defined and a rounding offset is adaptively assigned to each macroblock based on the content characteristics. The quantization step size is then calculated for the a particular macroblock according to another content characteristic of the macroblock such that the encoding of the particular macroblock is performed in response to the calculated quantization step size and the rounding offset value of the first block.
摘要:
There are provided methods and apparatus for efficient first-pass encoding in a multi-pass encoder. An apparatus includes a multi-pass video encoder for performing a first-pass encoding of input image data for at least one picture by sub-sampling at least a portion of the input image data prior to the first-pass encoding. The sub-sampling is at least one of spatial sub-sampling and temporal sub-sampling.
摘要:
There are provided methods and apparatus for enhanced performance in a multi-pass video encoder. An apparatus includes a video encoder for encoding a video bitstream. The apparatus further includes a video quality analyzer, in signal communication with the encoder, for performing a video quality analysis of the video bitstream for a given encoding pass to detect encoder compression artifacts in the video bitstream, and providing to the encoder information relating to the encoder compression artifacts to enable a re-encoding setup of the encoder to reduce an occurrence of the encoder compression artifacts in subsequent re-encoding passes. At least one of the video quality analysis and the re-encoding setup are automated.
摘要:
There are provided methods and apparatus for enhanced performance in a multi-pass video encoder. An apparatus includes a video encoder for encoding a video bitstream. The apparatus further includes a video quality analyzer, in signal communication with the encoder, for performing a video quality analysis of the video bitstream for a given encoding pass to detect encoder compression artifacts in the video bitstream, and providing to the encoder information relating to the encoder compression artifacts to enable a re-encoding setup of the encoder to reduce an occurrence of the encoder compression artifacts in subsequent re-encoding passes. At least one of the video quality analysis and the re-encoding setup are automated.
摘要:
A method and apparatus are provided for improved video encoding using region of interest information. The apparatus includes an encoder for encoding a plurality of regions of a picture by determining, using region of interest detection, a respective probability that each of the plurality of regions belong to a region of interest, and adaptively controlling a respective quality of each of the plurality of regions based on a value of the respective probability.