H264 timestamp

Hardware Platform (Jetson / GPU) NX
• DeepStream Version 6.1.1
• JetPack Version (valid for Jetson only) 5.02
• TensorRT Version 8.4

I used ffmpeg to input a h264 stream. processing like foloows:
H.264 >> NVV4L2 >> NV12 buffer
I want to know whether NV12 buffer contains the timestamp of h264.
If yes, how to get it?
if no, where can I get it?
Thank you.

The pts is in the gstbuffer, not NV12 buffer.

Thank you.