Online and offline selection of extended long term reference picture retention
An encoder includes circuitry configured to receive a video, determine a plurality of long-term reference frames, determine a long-term reference retention time, and encode the video into a bitstream including the determined plurality of long-term reference fames and the determined retention time. Related apparatus, systems, techniques and articles are also described.
1. A video processor comprising:
a motion compensation processor;
an inverse quantizer and inverse transformer, wherein a plurality of pictures being reconstructed by using the inverse transformer and inverse quantizer to inverse transform and inverse quantize residual signals, and adding the residual signals to predictors generated by the motion compensation processor, the plurality of reconstructed pictures including first, second, and third reconstructed pictures; and
a buffer for storing the reconstructed pictures including the first, second and third pictures,
wherein the reconstructing comprises:
reconstructing the first picture by determining a first list of active reference pictures from the pictures in the buffer, one of the active reference pictures being a long term reference picture, and reconstructing a block of said first picture using a predictor from the long term reference picture;
reconstructing the second picture by determining a second list of active reference pictures from the pictures in the buffer, said second list not including the long term reference picture and, in response to at least one parameter generated by an encoder, determining that the long term reference picture has a status where it is inactive as a reference picture for the second picture while continuing to be stored in the buffer and eligible to be an active reference picture for a third picture; and
reconstructing the third picture by determining a third list of active reference pictures from the pictures in the buffer including, in response to at least one parameter generated by an encoder, changing the determination of the long term reference picture from inactive to active as a reference picture, and including the long term reference picture in the third list, and reconstructing a block from the third picture using a predictor from the long term reference picture,
the long term reference picture then being marked as unused for reference so that it is not eligible to be used as a reference picture for a subsequent picture and is removed from the buffer.
2. The video processor of claim 1 where the plurality of pictures are single view pictures.
3. The video processor of claim 1 wherein the long term reference picture is removed from the buffer when an increasing counting parameter reaches a predetermined value.
4. The video processor of claim 3 wherein the increasing counting parameter is a time related parameter.