[Bug]: h264Encode sample test from libra-utils uses IDR frame as ref picture all the time

### Which component impacted?

_No response_

### Is it regression? Good in old configuration?

None

### What happened?

I was debugging h264encode sample test app from Libra-utils repo.

The test uses IDR frame as reference frame for all P frames.

I would like to have such option:
1. IDR frame is writing to m_refPic[0]
2. P frame is writing to m_refPic[1] and reads from m_refPic[0]
3. second P fram eis writing to m_refPic[0] and read from m_refPic[1].

I would like to use P frames as reference frames for encoding.

Is it possible even?

Which linux app does this?

Thanks,
Maksym

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

Others

### What impacted?

_No response_

### Debug Information

_No response_

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

None