Muxer Could Not Multiplex Stream – Buffer Has No PTS

Issue Overview

Users are experiencing a "Buffer has no PTS" error when attempting to multiplex video streams using the Jetson Orin NX platform with DeepStream 6.2 and JetPack 5.1.1. The issue arises during the processing of RTSP streams from various camera models. While certain camera models (specifically from Amcrest) work without issue, others (such as those from Honeywell and Valucam) encounter this error after varying periods of operation, leading to instability in the streaming application. The error messages indicate that the muxer cannot multiplex the stream due to missing presentation timestamps (PTS), which are crucial for synchronizing multimedia streams.

Relevant Hardware and Software Specifications

• Hardware Platform: Jetson Orin NX
• DeepStream Version: 6.2
• JetPack Version: 5.1.1
• TensorRT Version: 5.1.1-b56
• Camera Models Tested:
  • Working: Amcrest NC224-XD/U, IP5M-T1277EW-AI, IP5M-T1179EB-28MM
  • Failing: Honeywell HBW2PER2, Starlight VD-2FR41-ZS, Valucam VC-EB4431R-Z

Possible Causes

1. Camera Compatibility Issues: The differing behavior between camera models suggests that some cameras may not be providing the necessary PTS data in their RTSP streams, leading to the muxer error.
2. GStreamer Pipeline Configuration: The configuration of the GStreamer pipeline may not handle certain input streams correctly, especially if multiple buffers with identical PTS values are received.
3. Buffer Management: When multiple buffers are received without unique PTS values, it can lead to situations where subsequent buffers are marked with Gst.CLOCK_TIME_NONE, causing the muxer to fail.
4. Software Bugs or Limitations: There may be inherent limitations or bugs within the version of DeepStream or GStreamer being used that affect how timestamps are processed.

Troubleshooting Steps, Solutions & Fixes

Step-by-Step Instructions

1. Verify Camera Stream Output:

   • Use a tool like gst-launch-1.0 to test the RTSP stream directly and check for PTS values:

     gst-launch-1.0 -e rtspsrc location=rtsp://<user:pwd>@<URL>:<port> latency=3000 drop-on-latency=true ! rtph264depay ! h264parse ! fakesink
     

   • Monitor the output for any PTS-related warnings or errors.

2. Inspect GStreamer Pipeline:

   • Review and modify the GStreamer pipeline to ensure that it can handle cases where multiple buffers have the same PTS:
     • Add probes to each element’s pads to print out PTS/DTS values for debugging.

3. Modify Buffer Handling Logic:

   • If possible, implement logic in your application to patch or assign PTS values manually when they are missing:
     • For example, use the PTS from the first buffer received when subsequent buffers lack valid timestamps.

4. Test with Different Camera Models:

   • Isolate and test each camera model individually to determine if specific models consistently fail or succeed in providing valid PTS data.

5. Consult GStreamer Community:

   • Since the issue is related to GStreamer, consider reaching out to the GStreamer community for insights or potential patches related to handling PTS in multiplexing scenarios.

6. Update Software Versions:

   • Ensure that you are using the latest versions of DeepStream and JetPack as updates may include bug fixes related to stream handling.

Recommended Fixes

• Users have found success by modifying their GStreamer pipelines to handle missing PTS values better and by adding logic to patch these values when necessary.
• Engaging with both NVIDIA’s DeepStream support and the GStreamer community may yield additional solutions or workarounds.

Best Practices for Future Prevention

• Regularly update both DeepStream and JetPack versions to benefit from improvements and bug fixes.
• Maintain thorough documentation of camera models used and their performance characteristics when integrated into your pipeline.
• Implement robust error handling in your streaming applications to gracefully manage issues related to buffer timestamps.

Unresolved Aspects and Further Investigation

• The root cause of why certain camera models fail while others succeed remains unclear; further investigation into specific camera firmware or RTSP implementation may be necessary.
• Users continue to seek more detailed guidance on modifying buffer handling within their applications as well as potential updates from NVIDIA regarding this issue.

By following these troubleshooting steps and solutions, users can address issues related to multiplexing streams on the Jetson Orin NX platform effectively while utilizing DeepStream SDK features.