DERIVATION OF RESAMPLING FILTERS FOR SCALABLE VIDEO CODING
A method for determining a resampling filter for resampling a video signal used in scalable video coding includes estimating a set of row filters based on a video signal. The video signal has a base resolution that is resampled to provide an output signal that enables more efficient coding of the video signal with an enhanced resolution higher than a base resolution. The set of row filters is applied to the video signal to generate a first output signal having rows that are interpolated to the enhanced resolution. A set of column filters is estimated based on the first output signal for resampling the columns in the video signal. The set of column filters is applied to the first output signal to generate a second output signal having columns as well as rows that are interpolated to the enhanced resolution.
1 . A method for determining a resampling filter for resampling a video signal for use in scalable video coding, comprising:
estimating a first set of filters based on a video signal and a second set of filters based on the video signal, the first set of filters being one of row or column filters for respectively resampling rows or columns in the video signal and the second set of filters being the other one of row or column filters for respectively resampling rows or columns in the video signal, the video signal having a base resolution that is resampled to provide an output signal that enables more efficient coding of the video signal with an enhanced resolution higher than a base resolution;
applying the first set of filters to the video signal to generate a first output signal having rows or columns that are interpolated to the enhanced resolution; and
applying the second set of filters to the first output signal to generate a second output signal having rows and columns that are interpolated to the enhanced resolution.
2 . The method of claim 1 wherein the filters in the first and second sets of filters are upsampling filters and further comprising transmitting coefficients of the filters from an encoder encoding an enhanced layer of the video signal to a decoder decoding the enhanced layer of the video signal.
3 . The method of claim 1 wherein the coefficients are transmitted at a unit level including at least one of sequence parameter set (SPS), picture parameter set (PPS), slice, largest coding unit (LCU), coding unit (CU), prediction unit (PU) and per color component.
4 . The method of claim 1 wherein estimating the first set of filters further comprises determining the first set of filters by minimizing an error between an upsampled version of the video signal and a target output.
5 . The method of claim 4 wherein the target output is the video signal with full resolution.
6 . The method of claim 1 further comprising transmitting a difference between coefficients of the filters and a specified set of coefficients from an encoder to a decoder.
7 . The method of claim 1 wherein the filters are selected per at least one of sequence, picture, slice, largest coding unit (LCU), coding unit (CU) and prediction unit (PU) levels.
8 . A resampling device for use in a video coder, comprising:
a first module for estimating a first set of filters based on a video signal, the video signal having a base resolution that is resampled to provide an output signal that enables more efficient coding of the video signal with an enhanced resolution higher than a base resolution, the first set of filters being one of row or column filters for respectively resampling rows or columns in the video signal and a second set of filters being the other one of row or column filters for respectively resampling rows or columns in the video signal;
a second module for applying the first set of filters to the video signal to generate a first output signal having rows or columns that are interpolated to the enhanced resolution;
a third module for estimating the second set of filters based on the first output signal for resampling rows or columns in the video signal; and
a fourth module for applying the second set of filters to the first output signal to generate a second output signal having columns as well as rows that are interpolated to the enhanced resolution.
9 . The resampling device of claim 8 wherein the filters in the first and second sets of filters are upsampling filters and further comprising transmitting coefficients of the filters from an encoder encoding an enhanced layer of the video signal to a decoder decoding the enhanced layer of the video signal.
10 . The resampling device of claim 8 wherein the coefficients are transmitted at a unit level including at least one of sequence parameter set (SPS), picture parameter set (PPS), slice, largest coding unit (LCU), coding unit (CU), prediction unit (PU) and per color component.
11 . The resampling device of claim 8 wherein estimating the first set of filters further comprises determining the first set of filters by minimizing a mean square error (MSE) between an upsampled version of the video signal and a target output.
12 . The resampling device of claim 11 wherein the target output is the video signal with full resolution.
13 . The resampling device of claim 8 further comprising transmitting a difference between coefficients of the filters and a specified set of coefficients from an encoder to a decoder.
14 . The resampling device of claim 8 wherein the filters are selected per at least one of sequence, picture, slice, largest coding unit (LCU), coding unit (CU) and prediction unit (PU) levels.
15 . One or more computer-readable storage media containing instructions which, when executed by one or more processors perform a method for determining a resampling filter for resampling a video signal for use in scalable video coding, the method comprising:
estimating a first set of filters based on a video signal, the video signal having a base resolution that is resampled to provide an output signal that enables more efficient coding of the video signal with an enhanced resolution higher than a base resolution, the first set of filters being one of row or column filters for respectively resampling rows or columns in the video signal and a second set of filters being the other one of row or column filters for respectively resampling rows or columns in the video signal;
applying the first set of filters to the video signal to generate a first output signal having rows or columns that are interpolated to the enhanced resolution;
estimating the second set of filters based on the first output signal for resampling rows or columns in the video signal;
applying the second set of filters to the video signal to generate a second output signal having rows or columns that are interpolated to the enhanced resolution; and
updating the estimate of the first set of filters based on the second output signal video.
16 . The one or more computer-readable storage media of claim 15 further comprising:
applying the updated first set of filters to the video signal to generate an updated first output signal having rows or columns that are interpolated to the enhanced resolution; and
updating the estimate of the second set of filters based on the updated first output signal for resampling rows or columns in the video signal.
17 . The one or more computer-readable storage media of claim 15 wherein estimating the second set of filters further includes estimating the second set of filters based on the video signal with full resolution.
18 . The one or more computer-readable storage media of claim 15 wherein estimating the first set of filters further comprises determining the first set of filters by minimizing an error between an upsampled version of the video signal and a target output.
19 . The one or more computer-readable storage media of claim 18 wherein the target output is the video signal with full resolution.
20 . The one or more computer-readable storage media of claim 15 further comprising transmitting a difference between coefficients of the filters and a specified set of coefficients from an encoder to a decoder.