Transmissão UDP RTSP GStreamer & Correção de latência para câmeras térmicas

Streaming RTSP com GStreamer – Uma verdadeira pergunta do cliente&Um caso (UDP versus TCP)

This article documents a real customer support conversation regarding RTSP streaming from our câmeras térmicas usando GStreamer.
We are sharing it in a Q&A dialog format so other customers facing similar issues can quickly follow the troubleshooting process.

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1. RTSP Stream Address

Customer:
Olá, we received your thermal cameras, everything works fine, obrigado, but we can’t seem to find the address for the RTSP stream. What is the /stream/sub?

Apoio, suporte:
Our camera RTSP stream URL is:

rtsp://192.168.2.254:554/live

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2. RTSP Latency Concern

Customer:
We tested the RTSP stream and noticed considerable latency compared to the management panel preview.

Apoio, suporte:
This is expected behavior. The web management preview uses an internal optimized pipeline, while RTSP depends on network conditions and client buffering.

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3. UDP Streaming Requirement

Customer:
The RTSP stream also doesn’t work on my player that expects UDP. How can I get a UDP stream?

Apoio, suporte:
May I know what player you are using? VLC?

Customer:
My player is GStreamer integrated in an Android app.

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4. UDP Unicast vs UDP Multicast

Apoio, suporte:
If the GStreamer client accesses the device using Multicast UDP, this is currently não suportado.
We need to clarify whether you are using UDP unicast ou Multicast UDP.

Customer:
My GStreamer pipeline uses rtspsrc com udp set in the protocols parâmetro.
I did not use the udp-mcast valor, so it should be UDP unicast.

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5. Platform Clarification

Apoio, suporte:
Is this GStreamer running on Windows, Linux, or Android?
Our software engineer would like to test on our side.

Customer:
My app uses GStreamer on Android, mas rtspsrc can also be tested on Linux.

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6. Known Linux GStreamer Issue (Reference Case)

Apoio, suporte:
We found a similar issue discussed in a Chinese technical forum.

Solução:
Uninstall the following plugin:

sudo apt-get remove gstreamer1.0-plugins-ugly

This plugin may send RTSP headers that some cameras cannot recognize, resulting in a denial-of-service error.

Referência:
https://forums.developer.nvidia.com/t/rtsp-gstreamer-simple-recieve-and-store-in-file/157535/14

Could you provide your rtspsrc pipeline (Linux preferred)? An app version is also acceptable for testing.

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7. RTSP DESCRIBE Header Compatibility

Apoio, suporte:
Another possible reason is that if the RTSP DESCRIBE request does not contain:

application/sdp

the device may refuse the service.

This validation logic may be too strict, and we plan to relax this condition in future firmware updates.

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8. Android GStreamer Version Confirmation

Customer:
On Android, I am using:

• gstreamer-1.0-android-universal-1.26.8

It does not include ugly plugins. My Makefile contains:

GSTREAMER_PLUGINS := \
    coreelements \
    playback \
    typefindfunctions \
    rtsp \
    rtp \
    rtpmanager \
    udp \
    tcp \
    videoparsersbad \
    androidmedia \
    opengl

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9. Suggested GStreamer Runtime Parameters

Apoio, suporte:
We recommend trying short-header=true em rtspsrc.

Customer:
Is that header for UDP?

Apoio, suporte:
It is an RTSP header option and often improves compatibility.

Exemplos:

gst-launch-1.0 rtspsrc location=rtsp://<ip>:<port>/<path> short-header=true

gst-launch-1.0 rtspsrc location=rtsp://<ip>:<port>/<path> do-rtcp=false short-header=true

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10. Internal Test Results (Linux)

Apoio, suporte:
Our engineer tested the RTSP stream using GStreamer 1.0 on Linux, and it worked correctly.

TCP example:

gst-launch-1.0 rtspsrc location="rtsp://192.168.2.254/live" \
  name=src \
  latency=0 \
  protocols=tcp \
src. \
  ! decodebin \
  ! autovideosink

UDP example (remove protocols=tcp):

gst-launch-1.0 rtspsrc location="rtsp://192.168.2.254/live" \
  name=src \
  latency=0 \
src. \
  ! decodebin \
  ! autovideosink

The internal logic between Linux and Android GStreamer is the same, so behavior should be consistent across platforms.

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11. Conclusão

This case highlights several important points when using RTSP with GStreamer:

• RTSP URL: rtsp://<camera_ip>:554/live
• UDP unicast é suportado; UDP multicast is not
• Avoid problematic plugins (Linux only)
• Tentar short-header=true for better compatibility
• Linux test results can generally be applied to Android

If you encounter similar issues, please provide your GStreamer pipeline or test client, and our engineering team will assist further.