Log hydrophone changes, map to L/R channels

[scottveirs]

As a system administrator, bioacoustic scientist, or developer
I want to be able to map the left and/or right channel of an audio data file (streamed HLS/DASH and/or archived FLAC) back to the make and model of the hydrophone(s), and ideally a unique identifier like a serial number.

Possible solutions:

1. Add .env variables for channel 1 vs 2 source description, ideally in a standard format like Make_Model_SN (e.g. Labcore_40_0023 or CRT_SQ26-08_SN003).
2. upload the .env file (minus any credentials) along with the latest.txt file OR log any metadata changes and/or field notes in some other mechanism, like a database with API, so it can be associated with the raw audio data and/or utilized dynamically in apps like the Orcasound player (context for hydrophone feed in v3 drawer).
3. An alternative to (2) above might be to include such variables within a swarm management tool and log any changes to them in a way that can be associated with the raw audio data...

[scottveirs]

• confirm how left/right mono inputs map to ring/tip on input jacks and on to final output channels (L/R in headphones) when CHANNELS=2 vs CHANNELS=1
• think about whether more explicit mapping of input/output channels is warranted as we move towards less ambiguity to support e.g localization or calibration efforts.
• consider if/when hydrophone specs should make it into raw audio filename and/or internal metadata (e.g. mp3 comment fields)

[scottveirs]

Struggled with this issue when troubleshooting a failing hydrophone in the new dual-element deployment at the MaST Center this week. No breakthroughs yet in efforts to add filtering by channel as ffmpeg flags within stream.sh ... but this is likely a helpful resource for further efforts -- https://trac.ffmpeg.org/wiki/AudioChannelManipulation