Methods and devices for temporal resampling modes and temporal resampling post filtering

A method for encoding a video, the method comprising:

• obtaining, by a device comprising a memory storing instructions and a processor in communication with the memory, a video;
• determining, by the device based on the video, a sequence-level temporal restoration flag for a picture sequence, and encoding the sequence-level temporal restoration flag into a coded video bitstream;
• when the sequence-level temporal restoration flag indicates that temporal sampling is enabled, determining, by the device based on the video, whether an interpolation mode or an extrapolation mode is used for the temporal sampling, and encoding a temporal restoration mode into the coded video bitstream;
• when the temporal restoration mode indicates the interpolation mode, determining, by the device based on the video, an interpolation ratio index indicating a temporal resampling ratio, and encoding the interpolation ratio index into the coded video bitstream;
• when the temporal restoration mode indicates the extrapolation mode, determining, by the device based on the video, an extrapolation ratio index indicating a temporal resampling ratio, and encoding the extrapolation ratio index into the coded video bitstream;
• and
• encoding, by the device, the video into the coded video bitstream by downsampling based on the temporal resampling ratio.

A non-transitory computer-readable storage medium storing a video bitstream that is generated by a video encoding method, the video encoding method comprising:

• signaling a sequence-level temporal restoration flag in the video bitstream, wherein the sequence-level temporal restoration flag is determined for a picture sequence in a video;
• when the sequence-level temporal restoration flag indicates that temporal sampling is enabled, signaling a temporal restoration mode in the video bitstream, wherein the temporal restoration mode is determined based on the video to indicate whether an interpolation mode or an extrapolation mode is used for the temporal sampling;
• when the temporal restoration mode indicates the interpolation mode, signaling an interpolation ratio index in the video bitstream, wherein the interpolation ratio index is determined based on the video to indicate a temporal resampling ratio;
• when the temporal restoration mode indicates the extrapolation mode, signaling an extrapolation ratio index in the video bitstream, wherein the extrapolation ratio index is determined based on the video to indicate a temporal resampling ratio;
• and
• encoding the video into the video bitstream by downsampling based on the temporal resampling ratio.