[Iaxclient-devel] How is the subclass of video packets calculated?

[Alexander V. <ava...@vo...>]

HI all,

I am examining the video code of iaxclient, and have one question. I 
cannot understand the bitwise operations used to calculate the subclass 
of video packets, in the following code:

for encoding the subclass:
fh->csub = compress_subclass(fr->af.subclass & ~0x1) | ((fr->af.subclass 
& 0x1) << 6);

for decoding the subclass:
subclass = uncompress_subclass(fh->csub & ~0x40) | ((fh->csub >> 6) & 0x1);
 
Could someone explain this, I think it would be useful to all to have 
this documented.

Best regards
Alexander Vassilev