Metadata key coming through empty from AAF - causing parse error

[timlehr]

Move issue from AcademySoftwareFoundation/OpenTimelineIO#520

Hey team,

Just stumbled across this issue, which was a fun one to try and debug! When reading an AAF out of Media Composer (a test project for us to look at TITLES clips) we're seeing an issue with how the metadata is being presented, causing a crash in the C++ JSON parser. Within the "Parameters" block, the first Key is empty, with a value of false e.g.

"Parameters": {
    "": false, 
    "Angle  ": "135", 
    "AvidEffectID": {}, 
    "AvidParameterByteOrder": 18761, 
    "Blue   ": "0", 
    "Bold": false, 
    "Color Gradient": false, 
    "Descenders": true, 
    ...
}

Any one have an idea as to what this field is supposed to be? If I manually add in a field it parses fine, but the OTIO that's being generated is coming out this way, meaning there's currently no way for us to read it without manually manipulating it.
AAF that's causing the error here:

TitlesTest_EmptyMetadataKey_190528.aaf.zip

If you generate an OTIO from this file, the offending code is on line 760, and again on line 854:

TitlesTest_EmpterMetadataKey_190528.aaf.otio.zip

[timlehr]

I confirmed this is still an issue with the main branch, we need to check this with #44.

[peter-targett]

Running otioconvert with the tip of OpenTimelineIO and the AAF adapter (with referenced changes in #44) worked for me.