[Bug]: program hung while qsv_h264 decoder always got MFX_WRN_DEVICE_BUSY

[siriusht]

Which component impacted?

Decode

Is it regression? Good in old configuration?

No, this issue exist a long time

What happened?

1. System requirement:
   Windows FFmpeg version 4.4, which enabled qsv_h264 decoder, use libmfx (version1.25) as frontend.

2. Reproduce step:
   I use FFmpeg libs in my video conference application. That is running as client app on Windows 10 system.
   Client APP receive 9 video streams(differenct video resolution) simutanously, which decoded by qsv_h264 decoder.

3. Errors:
   MFXVideoDECODE_DecodeFrameAsync always returns MFX_WRN_DEVICE_BUSY, that cause dead loop.

What's the usage scenario when you are seeing the problem?

Video Conference

What impacted?

Please fix it ASAP.

Debug Information

FFmpeg output no error message.

Do you want to contribute a patch to fix the issue?

Yes, I'm glad to submit a patch to fix it