Custom streamer.json didn't apply to WebRTC streamer

[Гурьянов Александр Сергеевич]

Hi, I following this docs https://anbox-cloud.io/docs/ref/webrtc-streamer to override default streamer config.

I created addon hq (means high-quality), and assing it to application. The source of addong is attached. It contains only pre-start hook with following code:

```
#!/bin/bash
mkdir -p /var/lib/anbox
echo '{
    "video": {
        "bitrate_limits": [
            { "num_pixels": 2073600, "fps": 60, "min_kbps": 3000, "max_kbps": 6000 },
        ]
    }
}' > /var/lib/anbox/streamer.json
```

I expect that for video <= 1080p bitrate will be between 3000-6000. However it didn't apply. Actually I tried lot of different variants, and also the code form docs page. When container is started I see following logs:

Dec 01 10:21:00 ams-ce47vs858reg22tli930 anbox-starter[149]: 2022/12/01 10:21:00 Executing hook pre-start for addon hq
...
Dec 01 10:21:00 ams-ce47vs858reg22tli930 anbox-starter[149]: I1201 10:21:00.262367 239 platform.cpp:183] Using display configuration: 960x540@25
...
platform.cpp:255] Loading streamer configuration from /var/lib/anbox/streamer.json
Dec 01 10:21:00 ams-ce47vs858reg22tli930 anbox-starter[149]: W1201 10:21:00.553076 239 platform.cpp:258] No streamer configuration available, using default settings
Dec 01 10:21:00 ams-ce47vs858reg22tli930 anbox-starter[149]: I1201 10:21:00.554193 239 platform.cpp:282] WebRTC platform successfully initialized

As you can see from logs, the streaming resolution is 960x540@25, so my rule should apply, but there is a message:
"No streamer configuration available, using default settings"

Evenmore if I connect to container with shell, I can see that file exists:

ubuntu@ip-172-31-12-114:~$ amc shell ce47vs858reg22tli930
root@ams-ce47vs858reg22tli930:~# cat /var/lib/anbox/streamer.json
{
    "video": {
        "bitrate_limits": [
            { "num_pixels": 2073600, "fps": 60, "min_kbps": 3000, "max_kbps": 6000 },
        ]
    }
}
root@ams-ce47vs858reg22tli930:~#

Either an error in the documentation or something does not work as expected.

[Simon Fels (morphis)]

Hey,

thanks for reporting your issue!

The reason your streamer.json doesn't get loaded is because it contains invalid JSON:

{
    "video": {
        "bitrate_limits": [
            { "num_pixels": 2073600, "fps": 60, "min_kbps": 3000, "max_kbps": 6000 },
        ]
    }
}

The comma at the bitrate limit line is not allowed and will fail the parser. You can verify yourself in a linter like https://jsonlint.com/

The following streamer.json will work and will be accepted by Anbox:

{
    "video": {
        "bitrate_limits": [
            { "num_pixels": 2073600, "fps": 60, "min_kbps": 3000, "max_kbps": 6000 }
        ]
    }
}

Anbox can be more verbose about logging such errors and we will improve that.

[Гурьянов Александр Сергеевич (caiiiycuk)]

Yep, this works!

Docs of anbox https://anbox-cloud.io/docs/ref/webrtc-streamer also contains invalid json. Please fix it.

Thank you for fast answer.

[Simon Fels (morphis)]

No problem. We will update the documentation as well to correct this.

[Simon Fels (morphis)]

Fixed by https://github.com/anbox-cloud/discourse-docs/pull/205