摘要:
An inter mode for encoding a video macroblock is selected. An initial analysis on the macroblock homogeneity is performed to quickly reduce the number of inter modes for which motion estimation and rate distortion calculation are to be performed. An inter mode is selected based on these calculations and sub-pixel motion estimation, at various sub-pixel interpolation granularities, is performed only on the selected inter mode. Sub-pixel motion estimation may be skipped for macroblocks that exhibit relatively low distortion at the integer pixel level.
摘要:
An inter mode for encoding a video macroblock is selected. An initial analysis on the macroblock homogeneity is performed to quickly reduce the number of inter modes for which motion estimation and rate distortion calculation are to be performed. An inter mode is selected based on these calculations and sub-pixel motion estimation, at various sub-pixel interpolation granularities, is performed only on the selected inter mode. Sub-pixel motion estimation may be skipped for macroblocks that exhibit relatively low distortion at the integer pixel level.
摘要:
A power-scalable hybrid technique to reduce blocking and ringing artifacts in low bit-rate block-based video coding is employed in connection with a modified decoder structure. Fast inverse motion compensation is applied directly in the compressed domain, so that the transform (e.g., DCT) coefficients of the current frame can be reconstructed from those of the previous frame. The spatial characteristics of each block is calculated from the DCT coefficients, and each block is classified as either low-activity or high-activity. For each low-activity block, its DC coefficient value and the DC coefficient values of the surrounding eight neighbor blocks are exploited to predict low frequency AC coefficients which reflect the original coefficients before quantization in the encoding stage. The predicted AC coefficients are inserted into the low activity blocks where blocking artifacts are most noticeable. Subject to available resources, this may be followed by spatial domain post-processing, in which two kinds of low-pass filters are adaptively applied, on a block-by-block basis, according to the classification of the particular block. Strong low-pass filtering is applied in low-activity blocks where the blocking artifacts are most noticeable, whereas weak low-pass filtering is applied in high-activity blocks where ringing noise as well as blocking artifacts may exist. In low activity blocks, the blocking artifacts are reduced by one dimensional horizontal and vertical low-pass filters which are selectively applied in either the horizontal and/or vertical direction depending on the locations and absolute values of the predicted AC coefficients. In high activity blocks, de-blocking and de-ringing is conducted by 2- or 3-tap filters, applied horizontally and/or vertically, which makes the architecture simple.
摘要:
A prediction mode for encoding data is selected using a reduced number of rate-distortion cost computations. This reduction in rate-distortion cost computations is caused by filtering the number of potential intra prediction modes based on two criteria. First, the number of potential prediction modes is reduced based on at least one characteristic of a quantization procedure performed during the encoding procedure. Second, the number of potential prediction modes is reduced based on an error value calculated for each of the potential prediction modes.
摘要:
A prediction mode for encoding data is selected using a reduced number of rate-distortion cost computations. This reduction in rate-distortion cost computations is caused by filtering the number of potential intra prediction modes based on two criteria. First, the number of potential prediction modes is reduced based on at least one characteristic of a quantization procedure performed during the encoding procedure. Second, the number of potential prediction modes is reduced based on an error value calculated for each of the potential prediction modes.
摘要:
Transform based distortion cost estimation, which may be used to calculate a rate distortion cost associated with a mode for encoding a macroblock, is described. In one embodiment of the invention, a distortion value for a particular mode is estimated within the transform domain, which allows for the elimination of both inverse transformation and inverse motion functions in this calculation. A spatial domain residual of an encoding mode is estimated by identifying a difference, within the transform domain, between a motion compensated prediction residual of a macroblock and its corresponding reconstructed signal. The estimated spatial domain residual may then be used in distortion matrix computations to estimate a distortion level, within the transform domain, for an encoding mode.
摘要:
Transform based distortion cost estimation, which may be used to calculate a rate distortion cost associated with a mode for encoding a macroblock, is described. In one embodiment of the invention, a distortion value for a particular mode is estimated within the transform domain, which allows for the elimination of both inverse transformation and inverse motion functions in this calculation. A spatial domain residual of an encoding mode is estimated by identifying a difference, within the transform domain, between a motion compensated prediction residual of a macroblock and its corresponding reconstructed signal. The estimated spatial domain residual may then be used in distortion matrix computations to estimate a distortion level, within the transform domain, for an encoding mode.
摘要:
An inter-mode for encoding a video macroblock is selected based on a comparison of at least two rate-distortion values associated with inter-modes. The number of potential inter-modes for encoding the video macroblock is initially reduced based on the rate-distortion calculation of the SKIP mode between the current macroblock and the collocated macroblock (corresponding to a 0,0 motion vector). Motion estimation is performed on the remaining inter-modes to identify reference blocks and motion vectors. The number of calculations performed in identifying the reference blocks and motion vectors is potentially reduced because associations between inter-modes are recognized and leveraged.
摘要:
An inter-mode for encoding a video macroblock is selected based on a comparison of at least two rate-distortion values associated with inter-modes. The number of potential inter-modes for encoding the video macroblock is initially reduced based on the rate-distortion calculation of the SKIP mode between the current macroblock and the collocated macroblock (corresponding to a 0,0 motion vector). Motion estimation is performed on the remaining inter-modes to identify reference blocks and motion vectors. The number of calculations performed in identifying the reference blocks and motion vectors is potentially reduced because associations between inter-modes are recognized and leveraged.
摘要:
A method for encoding video data to reduce blocking artifacts is provided. The method initiates with identifying a macro-block as being associated with a blocking artifact. For example the macro-block may be identified as a low activity macro-block or a high activity macro-block. Then, blocking artifacts introduced through a compression operation are mitigated by adjusting both a quantization parameter and an amount of bits generated from the quantization parameter. A video encoder and a system for processing image data associated with block based compression are provided.