Pcap field bit 15

[boxerab]

This line:

Pcap = 0x00020000; //for jph, Pcap^15 must be set

Here, you are setting 17th bit of Pcap.

Also, is the Pcap field not 16 bits ?

[aous72]

Pcap is 32 bits. Whenever a Pcap bit is set, a corresponding Ccap field shall be included in the CAP header; Ccap is 16 bits.

Pcap bits are counted from the most significant bit; perhaps, this is due to the big-endianness. For HTJ2K, Pcap^15 should be set. Perhaps the comment can be improved by saying "for jph, Pcap^15 must be set; the 15th MSB bit." I know this might seem weird, but this is how it is.

Cheers,
Aous

[boxerab]

Thanks, Aous. Yes, it is weird :) It's not clear from the standard that this is the case, and I couldn't find where it specifies that Pcap is 32 bits. Thanks for clarifying this :)

[boxerab]

Actually, I still don't think this is correct :) Even if it is big endian, the 15th MSB bit set should be
0x00008000 rather than 0x00020000 which is the 17th MSB.

[aous72]

Pcap is not in the original Part 1. It was added later. It is in the latest edition of Part 1.

The attached picture should make it clear; Pcap¹⁵ indicates JPH -- Perhaps describing it as 15th MSB is still not very clear.

It is weird because it is counted from the MSB, and because it starts with 1, not 0.
Cheers,
Aous.

Edit: corrected "addition" to "edition"

[boxerab]

Alright, I think I understand :) , but yes, I find this unusual.
Thanks,
Aaron