The error I am getting when I render a hardware vaapi loaded video with audio using h264_vaapi.mp4 is:

Assertion pic->display_order == pic->encode_order failed at libavcodec/vaapi_encode_h264.c:421

The code in libavcodec/vaapi_encode_h264.c is exactly the same for 8.1 as 9.0.2. I am continuing to investigate.

The errors Andrew reported are:

RenderFarmClient::main_loop: client started
[AVHWFramesContext @ 0xafddc0c0] Unsupported format: vaapi.
Failed to initialize HW frame context.
err: Invalid argument
[h264_vaapi @ 0xa7ddaf00] A hardware frames reference is required to
associate the encoding device.
FFMPEG::open_encoder err: Invalid argument
int FFMPEG::open_encoder(const char*, const char*):
open failed h264_vaapi:/dev/shm/dnxhd.mkv
Render::render_single: Session finished.
Render::render_single: Session finished.
** rendered 1 frames in 2.310 secs, 0.433 fps
FFMPEG::open_decoder: some stre