Page 1 of 1

NDI stream fps flagged incorrectly

Posted: Thu May 21, 2020 23:18
by SalG
Greetings,

It appears that Resolume is not flagging/tagging NDI streams correctly according to composition frame rate settings. The NDI stream appears to be always flagged 60fps regardless of composition settings.

While Sienna NDI Monitor on Mac will count the actual frames and report this info, NDI Studio Monitor and other apps report the frame rate always as 60fps.

Any plans to fix this soon?

We were evaluating PVP and Resolume Arena for NDI video playout and just ran into this issue. Our preference would be Resolume Arena but this issue appears to be a show stopper.

Thanks!
Sal

Re: NDI stream fps flagged incorrectly

Posted: Fri May 22, 2020 09:18
by Zoltán
Resolume frame rate is variable. If you have set a specific maximum FPS in the composition settings, that only caps the frame rate to the value. If you throw a lot of layers and effects at Resolume, your playback FPS will drop. The number you see in the review monitor is an average of the last 1 second.
The NDI stream obviously can't have the specified number of max frames, only the rendered amount. The stream data rate will also drop with less frames.

Changing the FPS flag in the stream dynamically could introduce issues on the receiver, and as I said, we only have an average number for it at any time, so it's not changed in the stream.

I'm wondering, how is this a show stopper for you?

Re: NDI stream fps flagged incorrectly

Posted: Fri May 22, 2020 20:54
by tauromesa
Reading through this was super useful, I was just having issues with my stream FPS and I was just thinking it had to do with the amount of layers and effects, guessing I'm going to be using a more simple relay and notification scheme from now on. Thank you so much

Re: NDI stream fps flagged incorrectly

Posted: Sat May 23, 2020 22:10
by SalG
Hi Zoltan,

In a broadcast/live event environment, an NDI receiver/converter (for example NDI to HDMI or SDI) will use this flag/tag and produce a 60fps signal (or may not produce anything at all as 60p is not broadcast standard). Depending on your signal chain and hardware (switch, router,etc), this may not be supported. The behavior in live streaming software is similar, vMix and others, for example, will struggle with this 60fps flagged signal as it’s expecting 60fps but not receiving 60fps, this results in frame drops reported and stuttered playback.

Supporting 23.98, 24, 25, 50, 29.97 & 59.94fps correctly tagged/flagged NDI streams would make Arena & Avenue fully compatible with broadcast and live event hardware. And one of the most powerful playback solutions out there (NDI Audio would also be important).

Our use case would be Resolume Avenue or Arena playing out (3) 1920x1080 29.97fps NDI streams, that in turn would be picked up by three NDI to SDI converters going into a switcher driving three screens (or directly to projectors). If we’re also live streaming the event, we would use something like vMix to pickup the NDI streams and incorporate those into the live stream.

The only software we’ve found that does this correctly is PVP (ProVideoPlayer) from Renewed Vision.But much less powerful than Arena, and not updated as often. Then you have the uber expensive playout software for tv stations from softron.tv, where you’re paying $1k per screen or output.

UPDATE: Dynamically changing NDI frame rate isn’t desired, however setting NDI frame rate to the same value as the max composition frame rate (set by user) is highly advantageous. Then it’s up to the user/artist to manage their layers and/or hardware to get consistent/constant frame rate.

Re: NDI stream fps flagged incorrectly

Posted: Tue May 26, 2020 12:47
by Zoltán
SalG wrote:
Sat May 23, 2020 22:10
Dynamically changing NDI frame rate isn’t desired, however setting NDI frame rate to the same value as the max composition frame rate (set by user) is highly advantageous. Then it’s up to the user/artist to manage their layers and/or hardware to get consistent/constant frame rate.
This could be doable. We'll see what we can do.