Nvv4l2decoder is changing aspect ratio

[p.promny]

• Hardware Platform (Jetson / GPU) Tesla T4
• DeepStream Version 5.1
• JetPack Version (valid for Jetson only)
• TensorRT Version
• NVIDIA GPU Driver Version (valid for GPU only) 470.57.02
• Issue Type( questions, new requirements, bugs) bug
• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing)
• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)

We discovered that the following pipeline is changing the resolution and aspect ratio of input video:

gst-launch-1.0 rtspsrc location=rtsp://  ! queue ! rtph264depay ! nvv4l2decoder ! nvv4l2h264enc ! h264parse ! splitmuxsink

If the input video is 2688x1520 then the output is the same. However in case of 848x480 (16:9) the output is 640x480 (4:3) and the video is extended vertically. This is a huge problem for us because we are running nvinfer on this video.

I was trying caps before nvv4l2decoder but it didn’t change the result.

[kesong]

I don’t see any plugin change the resolution in your pipeline. Do you mean loss pixel aspect ratio information?

[p.promny]

No I mean the output video is squeezed.
If I use:

gst-launch-1.0 rtspsrc location=rtsp://  ! queue ! rtph264depay ! h264parse ! splitmuxsink

On the same stream the output is 848x480.
with nvv4l2decoder ! nvv4l2h264enc I got 640x480 that is squeezed

[kesong]

Suppose video encoder/decoder shouldn’t change resolution. Can you add gst-launch-1.0 -v rtspsrc … to show the caps of the pipeline?

[p.promny]

Sorry. Issue was on my side I didn’t see that camera has:

Width: 640
Height: 480
Pixel aspect ratio: 126/95

That’s why pure gstreamer pipeline was producing 848x640 resolution and deepstrem was producing 640x480.
Thanks for your help.