1/We Claim;
1. A method comprising:
for a first interlaced video frame in a video sequence, encoding/decoding a bitplane signaled at frame layer for the first interlaced video frame, wherein the bitplane represents field/frame transform types for plural macroblocks of the first interlaced video frame; and
for a second interlaced video frame in the video sequence, for each of at least one but not all of plural macroblocks of the second interlaced video frame, processing a per macroblock field/frame transform type bit signaled at macroblock layer.
2. The method as claimed in claim 1, wherein the second interlaced video frame includes one or more intra macroblocks and one or more inter macroblocks, and wherein the per macroblock field/frame transform type bit is signaled for each of the one or more intra macroblocks but none of the one or more inter macroblocks.
3. The method as claimed in claim 2, wherein a different bitstream element represents field/frame transform type for each of the one or more inter macroblocks.
4. The method as claimed in claim 1, wherein the first interlaced video frame is an interlaced I-frame and the second interlaced video frame is an interlaced P-frame.
5. The method as claimed in claim 1, wherein the encoding/decoding the bitplane includes selecting an encoding/decoding mode from among plural available encoding/decoding modes.
6. The method as claimed in claim 5, wherein the plural available encoding/decoding modes include row-skip, column-skip, pair-wise VLC, group-of-six VLC, and one or more differential modes,
7. The method as claimed in claim 1, wherein for the first interlaced video frame, after decoding the bitplane, for each of the plural macroblocks of the first interlaced video frame, processing macroblock layer information for the macroblock based at least in part on the field/frame transform type signaled for the macroblock in the bitplane.
8. A decoder comprising:
means (980) for decoding bitplanes signaled at frame layer, wherein the bitplanes include a first bitplane for a first interlaced video frame, and wherein the first bitplane represents field/frame transform types for plural macroblocks of the first interlaced video frame; and
means (980,930) for processing per macroblock field/frame transform type bits signaled at macroblock layer, wherein the per macroblock field/frame transform type bits include a per macroblock field/frame transform type bit for each of one or more but not all of plural macroblocks of a second interlaced video frame.
9. The decoder as claimed in claim 8, wherein the second interlaced video frame is a motion-compensated frame, and wherein the means for processing per macroblock field/frame transform type bits processes macroblock field/frame transform type bits for intra macroblocks but not inter macroblocks of the second interlaced video frame.
10. The decoder as claimed in claim 8, wherein the first interlaced video frame is an interlaced 1-frame and the second interlaced video frame is an interlaced P-frame.
11. The decoder as claimed in claim 8 wherein a means is provided for selecting a bitplane decoding mode from among plural available bitplane decoding modes.
12. The decoder as claimed in claim 11, wherein the plural available decoding modes include row-skip, column-skip, pair-wise VLC, group-of-six VLC, and one or more differential modes.
13. The decoder as claimed in claim 8, wherein said means comprises entropy decoder (980).
14. A method comprising:
selecting a bitplane mode from a group of plural available bitplane encoding/decoding modes; and
processing a bitplane according to the selected bitplane mode, wherein the bitplane indicates AC prediction status information for plural macroblocks of a video picture.
15. The method as claimed in claim 14, wherein the AC prediction status information
indicates for each of the plural macroblocks whether or not the macroblock is coded
using AC prediction.
16. The method as claimed in claim 14, wherein the video picture is a progressive intra frame, an interlaced intra frame, or an interlaced intra field.
17. The method as claimed in claim 14, wherein for a second video picture, for each of at least one but not all of plural macroblocks of the second video picture, an AC prediction status bit signaled at macroblock layer is processed.
18. The method as claimed in claim 17, wherein the second video picture includes one or more intra macroblocks and one or more inter macroblocks, and wherein a per macroblock AC prediction status bit is signaled for each of the one or more intra macroblocks but not for any of the one or more inter macroblocks.
19. The method as claimed in claim 14, wherein the plural available bitplane encoding/decoding modes include row-skip, column-skip, pair-wise VLC, group-of-six VLC, and one or more differential modes.
20. The method as claimed in claim 14, wherein the processing comprises encoding.
21. The method as claimed in claim 14, wherein the processing comprises decoding.
22. A method comprising:
encoding a bitplane that indicates AC prediction status information for plural macroblocks of a video picture; and
signaling the encoded bitplane.
23. The method as claimed in claim 22, wherein the bitplane includes one AC prediction status bit for each of the plural macroblocks to indicate whether or not the macroblock is coded using AC prediction.
24. The method as claimed in claim 22, wherein the encoded bitplane is signaled at field or frame layer in a bitstream.
25. The method as claimed in claim 22, wherein for each of one or more intra macroblocks of a second video picture, an AC prediction status bit is signaled per macroblock at macroblock layer.
26. The method as claimed in claim 25, wherein the second video picture is a motion compensated picture.
27. The method as claimed in claim 25, wherein the second video picture is an intra-coded picture.
28. A method comprising:
receiving an encoded bitplane ; and
decoding the bitplane, wherein the bitplane indicates AC prediction status information for plural macroblocks of a video picture.
29. The method as claimed in claim 28, wherein the bitplane includes one AC prediction
status bit for each of the plural macroblocks to indicate whether or not the macroblock is
coded using AC prediction.
30. The method as claimed in claim 28, wherein the encoded bitplane is signaled at field or frame layer in a bitstream.

31. The method as claimed in claim 28, wherein for each of one or more intra macroblocks of a second video picture, an AC prediction status bit per macroblock is received at macroblock layer.
32. The method as claimed in claim 31, wherein the second video picture is a motion compensated picture,
33. The method as claimed in claim 31, wherein the second video picture is an intra-coded picture,