audioChannels property
Channels in the first audio track, 0 when the file has none.
Read because Apple refuses a preview over it, in an error that names
something else. A silent cut was refused with MOV_RESAVE_STEREO —
a channel layout code, for a file with no audio stream at all — after
the upload and a round trip through the ingestion queue. Apple's stated
requirement is stereo, and the track count is four boxes from the ones
already being walked, so the answer is free here and expensive there.
Implementation
final int audioChannels;