SCALABLE VIDEO CODING USING REFERENCE AND SCALED REFERENCE LAYER OFFSETS
A process for determining the selection of filters and input samples is provided for scalable video coding. The process provides for re-sampling using video data obtained from an encoder or decoder process of a base layer (BL) in a multi-layer system to improve quality in Scalable High Efficiency Video Coding (SHVC). In order to accommodate other applications such as interlace/progressive scalability and to increase the resolution of the alignment between layers, it is proposed that the phase offset adjustment parameters be signaled.
1 - 23 . (canceled)
24 . A device for implementing a video coding process for decoding a current picture, said decoder comprising:
a processor configured to:
determine whether offsets and phase shifts are present in at least one syntax structures at a picture level, where said offsets include a left offset, a top offset, a right offset, and a bottom offset, where said phrase shifts include a x phase shift and a y phase shift;
parse the at least one picture level syntax structures for the offsets and phase shifts for deriving an inter-layer reference picture, wherein the offsets and phase shifts signaled in syntax elements at the picture level are adaptive per picture;
derive the inter-layer reference picture from a decoded reference picture using the offsets and phase shifts, wherein the decoded reference picture is in a first layer in a plurality of layers and the inter-layer reference picture is in a second layer in the plurality of layers;
the derivation including a prediction of a value at a sample location in a current picture based on at least one corresponding value in the decoded reference picture;
the derivation including use of the offsets that specify at least one offset between a first picture sample in the current picture that is collocated with a picture sample of the decoded reference picture and a second picture sample in the current picture, the offsets for adjusting the predicted value sample location; and
decoding the current picture using the inter-layer reference picture including the predicted value at the adjusted predicted value sample location.
25 . The device of claim 24 , wherein the offsets are signaled in a pps_multilayer_extension syntax that is conditional on a pps_extension_type_flag[i] flag.
26 . The device of claim 24 , wherein the offsets are signaled conditional on a scaled_reference_offset_present_flag flag.
27 . The device of claim 24 , further comprising:
determining if a pps_extension_type_flag[i] is set to indicate presence of the pps_multilayer_extension syntax structure;
parsing the pps_multilayer_extension syntax structure if the pps_extension_type_flag[i] is set indicating presence of the pps_multilayer_extension syntax structure; and
determining if a scaled_reference_offset_present_flag flag is set to determine whether the offsets and phase shifts are present in the at least one syntax structures at the picture level.
28 . The device of claim 24 , wherein at least one of the offsets specifies an offset between a picture sample in the current picture that is collocated with a bottom-right picture sample of the decoded reference picture in the first layer and a bottom-right picture sample of the current picture.
29 . The device of claim 24 , wherein at least one of the offsets specifies an offset between a picture sample in the current picture that is collocated with a top-left picture sample of the decoded reference picture in the first layer and a top-left picture sample of the current picture.
30 . The device of claim 24 , wherein at least one of the offsets specifies a horizontal component and at least one of the offsets specifies a vertical component.
31 . The device of claim 30 , wherein for at least one of the horizontal component, a scaled_ref_layer_left_offset syntax element and a scaled_ref_layer_right_offset syntax element specifies the horizontal component of the at least one of the offsets, and for the vertical component at least one of, a scaled_ref_layer_top_offset syntax element and a scaled_ref_layer_bottom_offset syntax element specifies the vertical component of the at least one of the offsets.
32 . The device of claim 30 , wherein at least one of the offsets specifying a horizontal component and a vertical component specifies a horizontal offset between a picture sample in the current picture that is collocated with a top-left picture sample of the decoded reference picture in the first coding layer and a top-left picture sample of the current picture.
33 . The device of claim 30 , wherein at least one of the offsets specifying a horizontal component and a vertical component specifies a vertical offset between a picture sample in the current picture that is collocated with a bottom-right picture sample of the decoded reference picture in the first coding layer and a bottom-right picture sample of the current picture.
34 . The device of claim 24 wherein said left offset specifies a horizontal offset between an upper-left luma sample of the inter-layer reference picture and the current picture.
35 . A method that includes a processor for decoding a current picture by a decoder, said method comprising:
determining whether offsets and phase shifts are present in at least one syntax structures at a picture level, where said offsets include a plurality of offsets, where said phrase shifts include a plurality of phase shifts;
parsing the at least one picture level syntax structures for the offsets and phase shifts for deriving an inter-layer reference picture, wherein the offsets and phase shifts signaled in syntax elements are adaptive per picture;
deriving the inter-layer reference picture from a decoded reference picture using the offsets and phase shifts, wherein the decoded reference picture is in a first coding layer in a plurality of coding layers and the inter-layer reference picture is in a second coding layer in the plurality of coding layers;
the derivation including a prediction of a value at a sample location in the current picture based on at least one value in the decoded reference picture;
the derivation including use of the offsets that specify at least one offset between a first picture sample in the current picture with a picture sample of the decoded reference picture, the offsets for adjusting the predicted value sample location; and
decoding the current picture using the inter-layer reference picture including the predicted value at the adjusted predicted value sample location.
36 . A method that includes a processor for decoding a current picture by a decoder, said method comprising:
determining whether offsets and phase shifts are present in at least one syntax structures at a picture level, where said offsets include a plurality of offsets, where said phrase shifts include a plurality of phase shifts;
parsing the at least one picture level syntax structures for the offsets and phase shifts for deriving a reference picture, wherein the offsets and phase shifts signaled in syntax elements are adaptive per picture;
deriving the reference picture from a decoded reference picture using the offsets and phase shifts;
the derivation including a prediction of a value at a sample location in the current picture based on at least one value in the decoded reference picture;
the derivation including use of the offsets that specify at least one offset between a first picture sample in the current picture with a picture sample of the decoded reference picture, the offsets for adjusting the predicted value sample location; and
decoding the current picture using the reference picture including the predicted value at the adjusted predicted value sample location.