frigate .16.1, go2rtc audio conversion issues?

[jdcynical]

Describe the problem you are having

Image: ghcr.io/blakeblackshear/frigate:0.16.1-tensorrt
go2rtc in the container: go2rtc platform=linux/amd64 revision=fa580c5 version=1.9.9
Running on dedicated hardware, nvidia 3060 8 gig for video acceleration and object detection

Camera in question:
h.265, 2560x1440, 25 fps
mlaw audio, mono, 16 bit 8000 hz

This started after the update from .15.x to .16.1, where this one particular camera no longer would record to the storage. Live streaming still works fine.

I am aware that this is more than likely due to the stricter validation checks when recording files, where ulaw is not allowed in the container.

I found this discussion, and checked my go2rtc config, which was set correctly, with the add of #hardware at the end (I tried removing it to no effect, but would prefer to have it use hardware acceleration if possible).

I'm at a loss as to what I should change at this point.

Version

0.16.1-e664cb2

What browser(s) are you using?

firefox 143.0.4 (64-bit)

Frigate config file

go2rtc:
foscam_sub:
  - rtsp://user:pass@address:88/videoSub
  - ffmpeg:foscam_sub#audio=aac
foscam_main:
  - rtsp://user:pass@address:88/videoMain
  - ffmpeg:foscam_main#audio=aac

Frigate:
  back_porch:
  # foscam floodlight
    live:
      streams:
        foscam_sub: foscam_sub
      inputs:
        # sub
        - path: rtsp://localhost:8554/foscam_sub
          input_args: preset-rtsp-restream
          roles:
            - detect

        # main
        - path: rtsp://localhost:8554/foscam_main
          input_args: preset-rtsp-restream
          roles:
            - record

Relevant Frigate log output

2025-10-11 18:07:11.686595577  [ WARN:[email protected]] global cap.cpp:175 open VIDEOIO(CV_IMAGES): raised OpenCV exception:
2025-10-11 18:07:36.440205  2025-10-11 18:07:11.686599937
2025-10-11 18:07:11.686602770  OpenCV(4.11.0) /io/opencv/modules/videoio/src/cap_images.cpp:267: error: (-215:Assertion failed) number < max_number in function 'icvExtractPattern'
2025-10-11 18:07:36.440231  2025-10-11 18:07:11.686607604
2025-10-11 18:07:36.440240  2025-10-11 18:07:11.686608912
2025-10-11 18:07:11.700391978  [2025-10-11 18:07:11] frigate.record.maintainer      WARNING : Failed to probe corrupt segment /tmp/cache/[email protected]
2025-10-11 18:07:11.701271595  [2025-10-11 18:07:11] frigate.record.maintainer      WARNING : Discarding a corrupt recording segment: /tmp/cache/[email protected]
2025-10-11 18:07:28.049089684  [2025-10-11 18:07:28] ffmpeg.back_porch.record       ERROR   : [mp4 @ 0x5c5a676df0c0] Could not find tag for codec pcm_mulaw in stream #1, codec not currently supported in container
2025-10-11 18:07:28.049441953  [2025-10-11 18:07:28] ffmpeg.back_porch.record       ERROR   : [out#0/segment @ 0x5c5a676ddf00] Could not write header (incorrect codec parameters ?): Invalid argument
2025-10-11 18:07:28.049701826  [2025-10-11 18:07:28] watchdog.back_porch            INFO    : Terminating the existing ffmpeg process...
2025-10-11 18:07:28.049875818  [2025-10-11 18:07:28] watchdog.back_porch            INFO    : Waiting for ffmpeg to exit gracefully...
2025-10-11 18:07:31.697243481  [ WARN:[email protected]] global cap.cpp:175 open VIDEOIO(CV_IMAGES): raised OpenCV exception:
2025-10-11 18:07:36.440264  2025-10-11 18:07:31.697250241
2025-10-11 18:07:31.697255769  OpenCV(4.11.0) /io/opencv/modules/videoio/src/cap_images.cpp:267: error: (-215:Assertion failed) number < max_number in function 'icvExtractPattern'
2025-10-11 18:07:36.440276  2025-10-11 18:07:31.697258213
2025-10-11 18:07:36.440285  2025-10-11 18:07:31.697260569
2025-10-11 18:07:31.959316138  [2025-10-11 18:07:31] frigate.record.maintainer      WARNING : Failed to probe corrupt segment /tmp/cache/[email protected]
2025-10-11 18:07:31.959567375  [2025-10-11 18:07:31] frigate.record.maintainer      WARNING : Discarding a corrupt recording segment: /tmp/cache/[email protected]

Relevant go2rtc log output

2025-10-11 18:25:27.020320370  [INFO] Preparing new go2rtc config...
2025-10-11 18:25:27.434623634  [INFO] Starting go2rtc...
2025-10-11 18:25:27.508704690  18:25:27.508 INF go2rtc platform=linux/amd64 revision=fa580c5 version=1.9.9
2025-10-11 18:25:27.508708801  18:25:27.508 INF config path=/dev/shm/go2rtc.yaml
2025-10-11 18:25:27.509181704  18:25:27.509 INF [api] listen addr=:1984
2025-10-11 18:25:27.509363834  18:25:27.509 INF [rtsp] listen addr=:8554
2025-10-11 18:25:27.509799341  18:25:27.509 INF [webrtc] listen addr=:8555
2025-10-11 18:25:36.534602815  [INFO] Starting go2rtc healthcheck service...

FFprobe output from your camera

Input #0, rtsp, from 'rtsp://$user:$pass@$address:88/videoMain':
  Metadata:
    title           : IP Camera Video
    comment         : videoMain
  Duration: N/A, start: 0.000000, bitrate: N/A
  Stream #0:0: Video: hevc (Main), yuv420p(tv), 2560x1440, 25 fps, 25 tbr, 90k tbn
  Stream #0:1: Audio: pcm_mulaw, 8000 Hz, 1 channels, s16, 64 kb/s

Frigate stats

No response

Operating system

Other Linux

Install method

Docker Compose

Object Detector

Other

Network connection

Mixed

Camera make and model

foscam F41

Screenshots of the Frigate UI's System metrics pages

Any other information that may be helpful

No response

[inkeep-ai-assistant[bot]]

The issue you're experiencing is related to the pcm_mulaw audio codec not being supported in MP4 containers for recording. The error message [mp4 @ 0x5c5a676df0c0] Could not find tag for codec pcm_mulaw in stream #1, codec not currently supported in container indicates that your camera's mulaw audio format needs to be converted to AAC for recording (1).

Your go2rtc configuration appears correct, but there might be an issue with how the ffmpeg transcoding is being applied. When using the ffmpeg module in go2rtc, you should ensure the audio conversion is properly configured (1).

Try updating your go2rtc configuration to use the ffmpeg module explicitly:

go2rtc:
  streams:
    foscam_sub:
      - ffmpeg:rtsp://user:pass@address:88/videoSub#video=copy#audio=aac#hardware
    foscam_main:
      - ffmpeg:rtsp://user:pass@address:88/videoMain#video=copy#audio=aac#hardware

(1)

If you need to convert both audio and video streams, you can use:

go2rtc:
  streams:
    foscam_main:
      - rtsp://user:pass@address:88/videoMain
      - "ffmpeg:foscam_main#video=h264#audio=aac#hardware"

(1)

When using the ffmpeg module directly, you would add AAC audio like this:

go2rtc:
  streams:
    foscam_main:
      - "ffmpeg:rtsp://user:pass@address:88/videoMain#video=copy#audio=copy#audio=aac#hardware"

(1)

The key difference is using the ffmpeg module directly in the stream URL rather than creating a separate transcoding stream. This ensures that the audio conversion happens at the source level before Frigate attempts to record the stream.

📚 Sources:

1. Configuring go2rtc

---

Have another question? Just tag @inkeep.

[hawkeye217]

The AI is correct. Another easy way to transcode would be to use the preset-record-generic-audio-aac output args preset.

ffmpeg:
  ...
  output_args: 
    record: preset-record-generic-audio-aac

This was covered in the breaking changes in the 0.16 release notes.

[jdcynical]

Right, this did do the trick, changing the go2rtc config to ffmpeg:$rtspurl.

I don't quite understand why this particular format is needed, but it's working now as it did previously.

I can't wait to get rid of this camera, it's been a pain with it's oddball stream and lack of controls. Thanks for the quick confirmation. 👍

[hawkeye217]

Great! Glad it's working for you now.