Disable 2020B unless Codec2 provides it.

[tmiw]

Due to build issues with v1.8.0 as reported in #255 and in-progress Codec2 API changes in master, 2020B must be disabled in the source code by default. This PR will allow 2020B to be enabled as an option if Codec2/LPCNet master are used for the build.

[drowe67]

So if we are checking out codec2 v1.0.3 ... how do we get 2020B?

[tmiw]

The user would need to edit this script to use master instead (or link against a Codec2 built manually from it).

[drowe67]

@tmiw - the general approach looks fine 👍

[tmiw]

Hmm, slight problem. It appears lpcnet_get_hash() isn't in v0.2. That particular function was added in this commit. Should a v0.3 be released that's tagged at that commit? Is there another commit that should be used for v0.3 instead?

[drowe67]

Hmm, that's curious - so we have been using that function for two years, and I guess several freedv-gui releases. How have we been building and packaging freedv-gui? Perhaps we have just been using LPCNet/master?

[tmiw]

Hmm, that's curious - so we have been using that function for two years, and I guess several freedv-gui releases. How have we been building and packaging freedv-gui? Perhaps we have just been using LPCNet/master?

Yeah, we've just been using master. I'd say to just continue using master except that there are likely API changes vs. 0.2, right?

[drowe67]

Yes good point about the LPCNet API changing. That in turn implies the need for codec2/master, or, as you suggest, and earlier version of LPCNet, if we stick with codec2 1.0.3

Yikes, this is all getting messy 🤔

How about this:

1. I'll look at codec2/master and see if I can make the minimum changes to make freedv_api.h compatible with existing applications - it was really just that one variable/structure.
2. I wont worry about the 2020C work for now, will do that later.
3. This implies we'll release 2020B into the wild now, which I'm not 100% happy with (as I'd like to compare it with 2020C first). Meh.
4. We can then have a another try at a codec2 1.0.4 release, and do a 0.3 LPCNet release off LPCNet/master.

Does that plan work for you @tmiw ?

[tmiw]

Does that plan work for you @tmiw ?

That works. Once (4) is done, I'll update the build scripts again, confirm that all platforms build, then merge and release 1.8.1. 👍