2.2.4.2.1.2 RFX_PROGRESSIVE_FRAME_BEGIN
The RFX_PROGRESSIVE_FRAME_BEGIN structure marks the beginning of the frame in the codec payload. This block MUST appear only once, before any RFX_PROGRESSIVE_REGION (section 2.2.4.2.1.5) blocks but after the RFX_PROGRESSIVE_CONTEXT (section 2.2.4.2.1.4) block.
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blockLen |
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frameIndex |
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regionCount |
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regions (variable) |
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blockType (2 bytes): A 16-bit unsigned integer that specifies the block type. This field MUST be set to WBT_FRAME_BEGIN (0xCCC1).
blockLen (4 bytes): A 32-bit unsigned integer that specifies the size, in bytes, of the RFX_PROGRESSIVE_FRAME_BEGIN block, excluding the size of the regions field. This field MUST be set to 12 (0x0000000C).
frameIndex (4 bytes): A 32-bit unsigned integer that specifies the frame index. This value SHOULD be ignored by the decoder.
regionCount (2 bytes): A 16-bit unsigned integer that specifies the number of RFX_PROGRESSIVE_REGION blocks that follow this RFX_PROGRESSIVE_FRAME_BEGIN block.
regions (variable): An array of RFX_PROGRESSIVE_REGION (section 2.2.4.2.1.5) blocks. The number of elements in this array is specified by the regionCount field. If the number of elements specified by the regionCount field is larger than the actual number of elements in the regions field, the decoder SHOULD ignore this inconsistency.