topic Re: [IMX8MP] How to resolve VCEncStrmEncode: ERROR HW bus access error in i.MX Processors

[IMX8MP] How to resolve VCEncStrmEncode: ERROR HW bus access error

b_m — Thu, 16 Jan 2025 00:29:34 GMT

Hi Community

I am trying to make an app that performs asynchronous encoding/decoding over multiple threads, using VPU wrapper. Each thread has an infinite loop and within that loop the following is performed:

1. Create VPU encoder/decoder instance via VPU_EncOpen/VPU_DecOpen
2. Perform actual encoding/decoding
3. Close VPU encoder/decoder instance via VPU_EncClose/VPU_DecClose

The app seems to run fine at first, but after few hours (at least 2 hours) VPU_EncEncodeFrame from above #2 returns -1,
and VPU log shows "VCEncStrmEncode: ERROR HW bus access error".

It is safe to assume that this error is due to multiple VPU instances running, but isn't this a supported feature of IMX8MP's VPU? Meaning, the app does not need to handle anything regarding multiple VPU instances running (e.g. checking if VPU is busy) since this would be taken care of by the VPU wrapper, supposedly.

Since there is no VPU manual specifically for IMX8MP, I'm attaching below IMX6's manual. I assume Multi-Instances feature is also supported in IMX8MP.

Re: [IMX8MP] How to resolve VCEncStrmEncode: ERROR HW bus access error

Bio_TICFSL — Thu, 16 Jan 2025 14:09:53 GMT

Hello,

Multiple instances are supported but in this apparently the vpu is full checking the stream encodes, try to give more latency the vpu just can process one image at the time, so give it more time to complete the action.

Regards

Re: [IMX8MP] How to resolve VCEncStrmEncode: ERROR HW bus access error

b_m — Fri, 17 Jan 2025 02:12:20 GMT

Hi @Bio_TICFSL , thanks for replying.

Are you suggesting to add intentional delays (e.g. doing std::this_thread::sleep_for(X)); after every encoding/decoding? This doesn't sound optimal especially for real-time systems.

It would have been helpful if VPU wrapper has an API to check VPU status (like the vpu_IsBusy() from i.MX 6 VPU API) so I could encode/decode only when VPU is actually free.

Re: [IMX8MP] How to resolve VCEncStrmEncode: ERROR HW bus access error

Bio_TICFSL — Fri, 17 Jan 2025 13:56:08 GMT

Hello,

I agree with you this must not happens, I will send a request to developers in order to upgrade the driver for VPU.

Regards