RTSP Stream plays at lower FPS than in ffplay/VLC

[zjarri]

I have an RTSP stream that I'd like to display in my WinUI3 application. Since I need the stream to playback as close as possible to "realtime," I've set the following flags, which work fine for me:

Config.Demuxer.FormatOpt["fflags"] = "nobuffer";
Config.Decoder.LowDelay = true;

Basically, after setting the buffer to 0, the desired result is achieved. However, here comes my issue. When the same input source is played on either ffplay or VLC, everything works correctly—the timing is right, and the video is smooth. But when played through Flyleaf, the timing remains correct, but the video feels like it's playing at only half the FPS; it is not smooth at all.

What can I do about this?

[SuRGeoNix]

Hi @zjarri, did you try to set this?

Config.Player.MaxLatency = TimeSpan.FromMilliseconds(500).Ticks;

[zjarri]

Unfortunately, due to data protection reasons, I cannot share the RTSP stream. In fact, even if that weren’t the case, the stream runs on a local network that is completely isolated from the internet, so external access wouldn’t be possible.

I may be able to provide a trace log later today, but I want to make sure it includes the relevant details. Could you let me know the best way to generate a useful log? If needed, I can also provide a private showcase of the issue—just let me know how you'd like to proceed.

Thanks for your understanding!

[SuRGeoNix]

I would try the following @zjarri

• Disable audio to make sure that issues is with video / format
• Give a try with Flyleaf v3.7.52 that it was using older FFmpeg version to check whether the issue is with FFmpeg
• Set both Flyleaf and FFmpeg logging to trace and I will wait until the issue happens for few seconds
• Increase the Max latency from 500ms to 2seconds and see if that fixes also the issue

Make sure you delete the Urls / hosts / usernames / passwords from the log file and upload it here or send me an email.

[zjarri]

Hi @SuRGeoNix,

I wasn’t able to generate a log today, but I’ll have access to the camera again on Monday. I’ll provide the log as soon as possible after that.

Thanks for your patience!

[zjarri]

Hi @SuRGeoNix,

I’ve just sent you an email with the trace log and a sample video.

Thanks again for your help!

[SuRGeoNix]

Replied by email: probably the issue was by setting the LowDelay to true (which MaxLatency enables either way by default). Should be resolved by disabling it (after setting the MaxLatency)

[SuRGeoNix]

Bit late but this might fixed it now 9c8caff

It seems that FFmpeg sets the skip_frame to Default which might drop frames in rtsp/udp etc...