4k preview freezing while decoding/rendering

[Hariharan J]

Hi Jonas Danielsson,
Thank you for your suggestion regarding the udp-buffer-size parameter and the system-level rmem_max configuration.
I have applied the recommended changes as follows:

  *
Set udp-buffer-size=16777216 in the GStreamer pipeline
  *
Updated the system parameter using:
sysctl -w net.core.rmem_max=16777216

However, the playback issue still persists—particularly stuttering and occasional freezing when playing back the recorded 4K stream. Additionally, we double-checked and confirmed that the stream is H.264 encoded, not AV1, so we are in the process of updating our playback pipeline to use the correct decoder.
We would appreciate any further guidance you could provide, especially on:

  *
Recommended decoding pipelines for 4K H.264 video with low latency
  *
Any known limitations or best practices for high-resolution RTSP decoding and playback
  *
Whether additional buffering, pipeline synchronization, or format adjustments may help improve smoothness

Thanks again for your support.
Best regards,
Hariharan J.

________________________________
From: Jonas Danielsson <jonas.danielsson at spiideo.com>
Sent: Wednesday, May 28, 2025 1:57 PM
To: Discussion of the development of and with GStreamer <gstreamer-devel at lists.freedesktop.org>
Cc: Manikandan Valaguru <manikandan.v at e-consystems.com>; Sandheepkumar M <sandheepkumar.m at e-consystems.com>; Suryaprakash DP <suryaprakash.dp at e-consystems.com>; Hariharan J <hariharan.j at e-consystems.com>
Subject: Re: 4k preview freezing while decoding/rendering

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Hello,

I suspect you  need to set the udp-buffer-size property of the rtspsrc
to handle the large 4K images:
https://gstreamer.freedesktop.org/documentation/rtsp/rtspsrc.html?gi-language=c#rtspsrc:udp-buffer-size

As well as make sure you allow large UDP buffer-size on your host:

Example:
sysctl -w net.core.rmem_max=16777216
rtspsrc udp-buffer-size=16777216

All the best
Jonas

On Wed, 28 May 2025 at 09:40, Manikandan Valaguru via gstreamer-devel
<gstreamer-devel at lists.freedesktop.org> wrote:
>
> Hi,
> We're currently using the following GStreamer pipeline to store 4K video from an RTSP stream:
> "gst-launch-1.0 -e rtspsrc latency=0 location=rtsp://192.168.1.13:5005/videodata ! rtph264depay ! h264parse ! mp4mux ! filesink location=file.mp4"
> The recorded video is then played back using the following pipeline:
> "gst-launch-1.0 filesrc location=videoplayback.mp4 ! qtdemux ! av1parse ! av1dec ! videoconvert ! xvimagesink sync=false "
> However, during playback, we are experiencing stuttering and occasional freezing in the video output. We've attached the video file that exhibits the issue for your reference.
>
> https://drive.google.com/drive/folders/1GvWKAHgY297onzoTD6ff0h17F_6aEWSM
> We suspect the problem might be related to decoding or rendering limitations, possibly due to incorrect pipeline elements or playback configuration. We're especially unsure about the use of av1parse and av1dec, given that the original stream is H.264 encoded.
> We would greatly appreciate your insights on:
>
> Whether the playback pipeline is appropriate for the saved file format.
> If any optimizations or changes can improve the smoothness of playback.
> Any known issues with hardware/software decoding of high-resolution streams.
>
> Thanks in advance for your help!
> Regards,
> Manikandan
>
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