Understanding go2rtc vs. camera streams and configuration

[natevw]

There's several things that are really unclear to me about "streams" to me. For starters, I think I kind of get how I can set up multiple separate streams per-camera, like:

go2rtc:
  streams:
    some_name: 
      - "ffmeg/rtsp:…"
    some_name_sub: 
      - "…"

That mostly makes sense, but already a few things don't seem super well-documented. How important is the name of each stream? Is the suffix _sub specially meaningful or could I just as well pick any other arbitrary name/ending like some_name_alternate or lofi-some_name? I wouldn't think the names had any meaning at all except that I noticed that with full redundancy like:

go2rtc:
  streams:
    exact_shared_name: 
      - "ffmpeg:…"

cameras:
  exact_shared_name:
    ffmpeg:
      inputs:
        - path: rtsp:https://127.0.0.1:8554/exact_shared_name

then Frigate would enable multiple options mse and webrtc but if I tried to split up the more permanent camera device/host name from a more semantic "where this camera is currently deployed/aimed" name like:

go2rtc:
  streams:
    device_name: 
      - "ffmpeg:…"

cameras:
  name_how_used:
    ffmpeg:
      inputs:
        - path: rtsp:https://127.0.0.1:8554/device_name

then Frigate would revert back to only showing the jsmpeg option alone. So it seems I'm really "supposed to" keep the names the same everywhere which is a bit of a bummer; is there a way to get the mse option without having the go2rtc section names matching exactly the camera section names?

---

The other thing that's still fairly unclear even after reading the camera-related guide pages repeatedly is all the multiple lines and places that all the options can go. For example in the go2rtc guide it gives an example:

go2rtc:
  streams:
    back:
      - rtsp:https://user:[email protected]:554/cam/realmonitor?channel=1&subtype=2
      - "ffmpeg:back#video=h264"

Now if I reference rtsp:https://127.0.0.1:8554/back as my camera ffmpeg path, which of those do I get? The first "rtsp" line or the second "h264" line? What does it mean to put multiple URLs within a single stream config block?

And also in the Reolink guides I see some examples like:

go2rtc:
  streams:
    your_reolink_camera: 
      - "ffmpeg:http:https://reolink_ip/flv?port=1935&app=bcs&stream=channel0_main.bcs&user=username&password=password#video=copy#audio=copy#audio=opus"

cameras:
  reolink:
    ffmpeg:
      inputs:
        - path: rtsp:https://127.0.0.1:8554/your_reolink_camera?video=copy&audio=aac
          input_args: preset-rtsp-restream

Now why does that have lines for #video=copy#audio=copy#audio=opus both in the go2rtc config section, but then also in the camera inputs there's a separate ?video=copy&audio=aac line in its link too! Under what circumstances would I need to or want to add video=copy also in the camera section instead of just in the go2rtc section?

Sorry for the long post with several questions, but I suspect they're all kind of interrelated. E.g. I just noticed in this last Reolink example that that go2rtc name does NOT match exactly the camera name, which seems to sort of halfway break Frigate in practice and force it to use only jsmpeg.

My best guess is that even within a single "stream" go2rtc actually can negotiate multiple video/audio suboptions — at least at the codec level? But then to actually provide a different resolution you can't do that as a suboption but have to set up a whole separate stream?

[NickM-27]

then Frigate would revert back to only showing the jsmpeg option alone. So it seems I'm really "supposed to" keep the names the same everywhere which is a bit of a bummer; is there a way to get the mse option without having the go2rtc section names matching exactly the camera section names?

this is covered in the live view docs

Now if I reference rtsp:https://127.0.0.1:8554/back as my camera ffmpeg path, which of those do I get? The first "rtsp" line or the second "h264" line? What does it mean to put multiple URLs within a single stream config block?

it depends what you request, if what is requested can be satisfied by the first stream then that is used. If the first stream is h265 and you request h264 specifically then go2rtc will engage the second line to try to satisfy that request.

Now why does that have lines for #video=copy#audio=copy#audio=opus both in the go2rtc config section, but then also in the camera inputs there's a separate ?video=copy&audio=aac line in its link too! Under what circumstances would I need to or want to add video=copy also in the camera section instead of just in the go2rtc section?

The ?video=copy... has been removed from the docs for 0.13 due to it being incorrect in some cases and confusing.

My best guess is that even within a single "stream" go2rtc actually can negotiate multiple video/audio suboptions — at least at the codec level? But then to actually provide a different resolution you can't do that as a suboption but have to set up a whole separate stream?

yes that is accurate