2.2.4.2.1.4 RFX_PROGRESSIVE_CONTEXT
The RFX_PROGRESSIVE_CONTEXT structure provides information about the compressed data. It is optional and SHOULD appear before the RFX_PROGRESSIVE_FRAME_BEGIN (section 2.2.4.2.1.2) block. If the block appears after the RFX_PROGRESSIVE_FRAME_BEGIN block, the decoder SHOULD process it.
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blockType |
blockLen |
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ctxId |
tileSize |
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flags |
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blockType (2 bytes): A 16-bit unsigned integer that specifies the block type. This field MUST be set to WBT_CONTEXT (0xCCC3).
blockLen (4 bytes): A 32-bit unsigned integer that specifies the size, in bytes, of the RFX_PROGRESSIVE_CONTEXT block. This field MUST be set to 10 (0x0000000A).
ctxId (1 byte): An 8-bit unsigned integer that specifies the context ID. This field SHOULD be set to 0x00. The decoder SHOULD ignore this value.
tileSize (2 bytes): A 16-bit unsigned integer that indicates the width and height of a square tile. This field MUST be set to 0x0040.
flags (1 byte): An 8-bit unsigned integer that contains context flags.
-
Flag
Meaning
RFX_SUBBAND_DIFFING
0x01
Indicates that sub-band diffing is enabled.