QMultimedia rtsp delay (or how to provide ffmpeg flags)

VLopez

Using Qt 6.5.1 from binaries.
I have managed to view a rtsp stream with QML setting the source to "rtsp://127.0.0.1:8554/back" in the mediaplayer example.

But the playback has 1-2 second delay. The server and client are on the same machine, and the camera is running at 640x480 30fps, it is not a bandwidth/cpu issue.

Furthermore, if I use ffplay to stream from the same server with this command
ffplay -rtsp_transport tcp rtsp://localhost:8554/back I see a similar delay.

But if I run with ffplay -rtsp_transport tcp rtsp://localhost:8554/back -fflags nobuffer -flags low_delay the delay is gone.

How can I pass these flags to the ffmpeg backend? I need this for a Linux and Android application.

SGaist

Hi and welcome to devnet,

AFAIK, it's currently not possible to do that kind customization.

You should check the bug report system to see if there's something related.

ivorymasters

@SGaist said in QMultimedia rtsp delay (or how to provide ffmpeg flags):

Hi and welcome to devnet,

AFAIK, it's currently not possible to do that kind customization.

You should check the bug report system to see if there's something related.

I finally understood the problem. Thank you!

lemons

@ivorymasters try setting the playbackRate to 0 before playing the stream.