Interpolation of video compression frames
Coding techniques for a video image compression system involve improving an image quality of a sequence of two or more bi-directionally predicted intermediate frames, where each of the frames includes multiple pixels. One method involves determining a brightness value of at least one pixel of each bi-directionally predicted intermediate frame in the sequence as an equal average of brightness values of pixels in non-bidirectionally predicted frames bracketing the sequence of bi-directionally predicted intermediate frames. The brightness values of the pixels in at least one of the non-bidirectionally predicted frames is converted from a non-linear representation.
1. A method of video compression, the method comprising:
providing an input sequence of frames each including picture regions; and
processing, with a processor, the input sequence of frames to generate an output sequence of frames including referenceable frames and at least one bi-directionally predicted frame,
wherein:
the processing comprises determining unequal weights, the unequal weights being used to interpolate pixel values of at least one picture region of at least one bi-directionally predicted frame by reference to two or more referenceable frames in the input sequence,
the frames comprise chroma signal components and luminance signal components,
the processing comprises processing the chroma signal components of the frames differently from processing the luminance signal components of the frames, and
the unequal weights are utilized for pixel luminance values and pixel chroma values of at least the one picture region.
2. The method of claim 1 , wherein the referenceable frames comprise predicted frames and intra frames.
3. The method of claim 1 , further comprising encoding the picture region of the bi-directionally predicted frame by reference to two or more subsequent referenceable frames in the sequence.
4. The method of claim 1 , further comprising identifying at least one of the two or more referenceable frames.
5. The method of claim 1 , further comprising providing access to a first weight that is less than zero and a second weight that is greater than +1.0.
6. The method of claim 1 , further comprising providing access to the unequal weights in a range of −1.0 to +2.0.
7. The method of claim 1 , further comprising providing access to at least one weight of +2.0 or greater.
8. The method of claim 1 , further comprising encoding using unequal pixel values of selected picture regions from the two or more referenceable frames.
9. The method of claim 8 , further comprising scaling at least one of a plurality of motion vectors by a frame scale fraction of less than zero or greater than one.
10. The method of claim 9 , wherein a motion vector delta corresponds to each motion vector.
11. A video image compression system for video image compression, the system comprising:
a processor configured to execute instructions to process an input sequence of frames each including picture regions to generate an output sequence of frames including referenceable frames and at least one bi-directionally predicted frame,
wherein:
the processing of the processor comprises executing instructions to determine unequal weights, the unequal weights being used to interpolate pixel values of at least one picture region of at least one bi-directionally predicted frame by reference to two or more referenceable frames in the input sequence,
the frames comprise chroma signal components and luminance signal components,
the processing comprises processing the chroma signal components of the frames differently from processing the luminance signal components of the frames, and
the unequal weights are utilized for pixel luminance values and pixel chroma values of at least the one picture region.
12. The system of claim 11 , wherein the referenceable frames comprise predicted frames and intra frames.
13. The system of claim 11 , further comprising an encoder configured to encode the picture region of the bi-directionally predicted frame by reference to two or more subsequent referenceable frames in the sequence.
14. The system of claim 11 , wherein the processor is configured to execute instructions to identify at least one of the two or more referenceable frames.
15. The system of claim 11 , wherein at least a first weight is less than zero and a second weight that is greater than +1.0.
16. The system of claim 11 , wherein the unequal weights are in a range of −1.0 to +2.0.
17. The system of claim 11 , wherein at least one weight of the unequal weights is +2.0 or greater.
18. The system of claim 11 , further comprising an encoder configured to encode using unequal pixel values of selected picture regions from the two or more referenceable frames.
19. The system of claim 18 , wherein at least one of a plurality of motion vectors is scaled by a frame scale fraction of less than zero or greater than one.
20. The system of claim 19 , wherein a motion vector delta corresponds to each motion vector.
21. The system of claim 11 , further comprising:
a data storage system;
an input port; and
an output port.
22. A method of video decoding, the method comprising:
receiving a coded input sequence of frames each including picture regions; and
processing, with a processor, the input sequence of frames to generate an output sequence of frames including referenceable frames and at least one bi-directionally predicted frame,
wherein the processing comprises:
receiving unequal weights, the unequal weights being used to interpolate pixel values of at least one picture region of at least one bi-directionally predicted frame by reference to two or more referenceable frames in the input sequence, the frames comprise chroma signal components and luminance signal components,
processing the chroma signal components of the frames differently from processing the luminance signal components of the frames, and
utilizing the unequal weights for pixel luminance values and pixel chroma values of at least the one picture region.
23. A method of video decompression, the method comprising:
utilizing an input sequence of frames each including picture regions; and
processing, with a processor, the input sequence of frames to generate an output sequence of frames including referenceable frames and at least one bi-directionally predicted frame,
wherein:
the processing comprises determining unequal weights, the unequal weights being used to interpolate pixel values of at least one picture region of at least one bi-directionally predicted frame by reference to two or more referenceable frames in the input sequence,
the frames comprise chroma signal components and luminance signal components, and
the processing comprises determining separate weights for the chroma signal components and the luminance signal components.
24. The method of claim 23 , further comprising performing video decompression with a decoder in a video image system.
25. The method of claim 23 , further comprising performing the processing with a decoder.