[Bug]: ffmpeg_presets.py:281 — parse_preset_hardware_acceleration_encode() passes only 2 args to format() when hwaccel_args is a list

[ryzendigo]

Checklist

• I have updated to the latest available Frigate version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in incognito mode to rule out problems with any third party extensions or plugins I have installed.
• I have asked the AI at https://docs.frigate.video about my issue.

Describe the problem you are having

When birdseye.restream is true and hwaccel_args is configured as a list (e.g. VAAPI),
parse_preset_hardware_acceleration_encode() in ffmpeg_presets.py at line 281 calls:

  return arg_map["default"].format(input, output)

This passes only 2 positional arguments, but the default birdseye preset string contains 3 placeholders:

  "{0} -hide_banner {1} -c:v libx264 ... {2}"

{0} = ffmpeg_path, {1} = input, {2} = output. The missing ffmpeg_path causes:

  IndexError: Replacement index 2 out of range for positional args tuple

This crashes create_config.py, which runs on every go2rtc start. go2rtc enters a restart loop and ALL camera streams
go down — not just birdseye.

The fix is to include ffmpeg_path as the first argument:

  return arg_map["default"].format(ffmpeg_path, input, output)

The ffmpeg_path variable is already available in scope at that point.

Steps to reproduce

1. Configure hwaccel_args as a list (not a preset string), e.g. for VAAPI:
   ffmpeg:
   hwaccel_args:
   - -hwaccel
   - vaapi
   - -hwaccel_device
   - /dev/dri/renderD128
2. Enable birdseye restream:
   birdseye:
   enabled: true
   restream: true
3. Start Frigate — go2rtc enters a crash loop, all camera streams fail

Version

0.17.0-f0d69f7

In which browser(s) are you experiencing the issue with?

N/A — backend bug, not browser-related

Frigate config file

ffmpeg:
    hwaccel_args:
      - -hwaccel
      - vaapi
      - -hwaccel_device
      - /dev/dri/renderD128

  birdseye:
    enabled: true
    restream: true
    width: 1920
    height: 1080

docker-compose file or Docker CLI command

will post if needed

Relevant Frigate log output

IndexError: Replacement index 2 out of range for positional args tuple

Relevant go2rtc log output

ERR [exec] timeout source="exec:/usr/lib/ffmpeg/7.0/bin/ffmpeg -hide_banner -f rawvideo -pix_fmt yuv420p -video_size
  1920x1080 -r 10 -i /tmp/cache/birdseye -c:v libx264 -g 50 -profile:v high -level:v 4.1 -preset:v superfast -tune:v
  zerolatency -rtsp_transport tcp -f rtsp rtsp://127.0.0.1:8554/..."

Operating system

Debian

Install method

Docker Compose

Network connection

Wired

Camera make and model

Dahua (multiple models)

Screenshots of the Frigate UI's System metrics pages

dont have any screenshots

Any other information that may be helpful

The bug is in the not isinstance(arg, str) branch of parse_preset_hardware_acceleration_encode().
When hwaccel_args is a string (preset name like "vaapi"), it takes a different code path that works correctly.
The bug only triggers when hwaccel_args is a list of individual arguments.

Workaround: bind-mount a patched ffmpeg_presets.py with line 281 changed to:
return arg_map["default"].format(ffmpeg_path, input, output)

[inkeep-ai-assistant[bot]]

This appears to be a valid bug report. Based on the documentation, when configuring hwaccel_args as a list (rather than using a preset string), the birdseye restream functionality can fail due to the missing ffmpeg_path argument in the format string.(1)(2)

The documentation shows that hwaccel_args can be configured either as a preset string (like "preset-vaapi") or as explicit arguments:(1)

ffmpeg:
  # Optional: global hwaccel args (default: auto detect)
  # NOTE: See hardware acceleration docs for your specific device
  hwaccel_args: "auto"

(1)

Workaround until this is fixed:

Use the preset string format instead of a list for your VAAPI configuration:(2)

ffmpeg:
  hwaccel_args: preset-vaapi

(1), (2)

The preset-vaapi preset is designed for Intel & AMD VAAPI hardware acceleration.(2)

If you need to specify a custom hwaccel_device path that differs from the default, you may need to continue using your bind-mount workaround until the bug is addressed in the codebase.

Your analysis of the root cause (missing ffmpeg_path as the first argument in the format call) and proposed fix appears correct based on the error message and the three-placeholder format string you've identified.

📚 Sources:

1. Full Reference Config
2. FFmpeg presets

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Have another question? Just tag @inkeep.

[hawkeye217]

Resolved in #22462