Clarify FLAC "number of channels"

[jwcullen]

§3.11.3

number of channels SHALL be set to 1. number of channels can be ignored because the real value can be determined from the Audio Element OBU and from the Frame_Header.

Note that FLAC adds one to the value in the bitstream to determine the number of channels represented. Signalling 0 represents one channel, signalling 1 represents two channels.

So I suggest clarifying that the spec intends to say the the bitstream must hold "1" and therefore represent two channels. This interpretation matches the pre-existing test vectors and agrees with IAMF-Opus and IAMF-AAC (by signalling two channels). Therefore clarifying this would simply be an editorial change.

I think it is incorrect, but a different reading would be that the bitstream must represents one channel, by holding a "0".