Selective prediction for intra-coding video data block
In a method of video data compression a video frame in a sequence of frames is divided into a number of macroblocks, a particular macroblock being adjacent to a number of previously coded macroblocks including both intra-coded and inter-coded macroblocks. The method includes selecting either a full prediction or limited prediction type in encoding the particular macroblock to provide a corresponding data bit stream, full prediction using both adjacent inter-coded and intra-coded macroblocks, and limited prediction using intra-coded macroblocks only. A signal is provided along with the bit stream to indicate the selected prediction type to a decoder disposed to recover data from the bit stream. The prediction type may be either signaled explicitly, such as by providing a code word in the bit stream, or may be inferred implicitly by selected values or levels of a coding variable.
1. A method of video data compression for use with a specified block included in a number of blocks derived by selectively dividing a video frame in a sequence of frames, said specified block being adjacent to a number of previously coded blocks including both intra-coded blocks and inter-coded blocks, said method comprising the steps of:
selecting a prediction type from a set comprising full prediction and limited prediction types, said full prediction type based on one or more of said intra-coded blocks and also one or more of said inter-coded blocks, and said limited prediction type based on one or more of said intra-coded blocks only;
using said selected prediction type in encoding said specified block to generate a data bit stream corresponding to said specified block; and
providing a signal along with said bit stream to indicate said selected prediction type to a decoder disposed to recover data of said specified block.
2. The method of claim 1 wherein:
said selected prediction type is signaled explicitly by a code word in said bit stream.
3. The method of claim 1 wherein:
said prediction type is signaled explicitly by a code word in a bit stream for a macroblock.
4. The method of claim 1 wherein:
said specified block is grouped together with a number of other blocks, and said selected prediction type is signaled explicitly by a code word in a bit stream for said group of blocks.
5. The method of claim 1 wherein:
said selected prediction type is signaled explicitly by a code word in the bit stream for said frame containing said specified block.
6. The method of claim 1 wherein:
said selected prediction type is signaled explicitly by a code word in a bit stream for said sequence of frames.
7. The method of claim 1 wherein:
said selected prediction type is signaled implicitly by the value of a selected coding variable.
8. The method of claim 1 wherein:
said selected prediction type is signaled implicitly by the quantization level of a quantizer.
9. The method of claim 1 wherein:
said prediction type applies to pixel levels of luma and chroma.
10. The method of claim 1 wherein:
said prediction type applies to transform coefficients for luma and chroma.
11. The method of claim 1 wherein:
said prediction is allowed over segment boundaries.
12. The method of claim 1 wherein:
said prediction is allowed only inside a segment containing said specified block.
13. The method of claim 1 wherein:
said specified block comprises a 16×16 macroblock.
14. The method of claim 1 wherein:
said selected prediction type is signaled implicitly by the choice of optional coding tools.
15. The method of claim 1 wherein:
said selected prediction type is signaled implicitly by a choice of profiles and/or levels.