Signaling for entry point frames with predicted first field

In a computing device that implements a video decoder, a method comprising:

• receiving, at the computing device that implements the video decoder, an entry point key frame comprising first and second interlaced video fields;
• with the computing device that implements the video decoder, decoding a first syntax element for the entry point key frame at a first syntax level in a bitstream, wherein the first syntax element is a frame coding mode for the entry point key frame, and wherein the frame coding mode indicates that the first and second interlaced video fields are arranged in the bitstream for decoding as individual fields;
• and
• with the computing device that implements the video decoder, decoding a second syntax element for the entry point key frame at the first syntax level in the bitstream, wherein the second syntax element indicates a field type for each of the first and second interlaced video fields in the entry point key frame, wherein the second syntax element can indicate one of plural different combinations of field types for the first and second interlaced video fields, respectively, the plural different combinations of field types including P/I, wherein the first interlaced video field in the entry point key frame is a P-field, and wherein the second interlaced video field in the entry point key frame is an intra-coded field.

In a computing device that implements a video decoder, a method comprising:

• receiving, at the computing device that implements the video decoder, an entry point key frame comprising first and second interlaced video fields;
• with the computing device that implements the video decoder, decoding a first syntax element for the entry point key frame at frame level in a bitstream, the first syntax element comprising a variable length code for a frame coding mode for the entry point key frame, wherein the frame coding mode indicates that the first and second interlaced video fields are arranged in the bitstream for decoding as individual fields;
• and
• with the computing device that implements the video decoder, decoding a second syntax element for the entry point key frame at frame level in the bitstream, the second syntax element comprising a single fixed length code that jointly indicates a field type for each of the first and second interlaced video fields, the second syntax element indicating a combination of different field types for the first and second interlaced video fields, respectively, in the entry point key frame, wherein the combination of different field types is P/I for the first and second interlaced video fields, respectively, wherein the first interlaced video field in the entry point key frame is a P-field, and wherein the second interlaced video field in the entry point key frame is an intra-coded field.