Problems with Datavideo NVS-20

Wowza Streaming Engine
1

Hello!

I have a Datavideo NVS-20 encoder and sending RTMP stream to Wowza server. The box does not have many parameters, just video inout, resolution, bitrate and mpeg profile.

When I choose 720p50 with 4mbit/s the clients experience constant and regular freezes and drops in the video stream. Upstream bandwidth from my site is 10mbit/s and the Wowza server has 1gbit/s connection. Server bandwidth during the live streaming was around 600mbit/s - and I had other events with up to 850mbit/s without any problems but encoded with FMLE at 1mbit/s

When I lowered the bitrate in steps of 500kbit/s the drops decreased but never vanished completely.

I will now try 2mbit/s but I don’t want to go lower because then the quality will be bad.

Do you have any experience with this Datavideo encoder or is there something special to tune for high bitrate streams?

And how to troubleshoot this kind of problems at all?

thanx and greetings,

Stephan

2

Hi Stephan,

Can you try setting your FMLE at 2mbit/s as you suggested and see how that works for you.

You could also look at experimenting with different sort buffer values, say 4000 (4 seconds) and lower.

Paul

3

I tested this coder too, the quality of video is very ugly even on high bitrates.

4

OK, I configured the sort buffer but it did not change the quality or stability with the NVS-20 encoder at 2mbit/s

Then I streamed from FMLE with 4mbit/s and guess what? absoluteley fine and stable.

I also tried the NVS-20 with local streaming mode and I connected a player directly to it - no problems.

My guess is that maybe the IP stack in the NVS-20 is not so efficient over WAN with Path MTU discovery, MSS size, etc …

Will next try and install a Wowza in my LAN and see if the problems persist.

Greetings,

Stephan

5

Update: same problems when streaming at 4 mbit/s over a 1gbit/s LAN to a local Wowza instance

===> NVS-20 is crap!

Best,

Stephan

6

yep, I am in contact with Datavideo Europe already.

This is what the Wowza says constantly when using the NVS-20:

2014-08-09 01:00:06 CEST comment server INFO 200 - TranscodingSession.updateBehindFilter[LamaOle/definst/live]: Video behind filter state change. New state: SKIP1FRAME - - - 122472.506 - - - -

2014-08-09 01:00:11 CEST comment server INFO 200 - TranscodingSession.updateBehindFilter[LamaOle/definst/live]: Video behind filter state change. New state: ALLFRAMESON - - - 122477.654 - - - -

2014-08-09 01:00:25 CEST comment server INFO 200 - TranscodingSession.updateBehindFilter[LamaOle/definst/live]: Video behind filter state change. New state: SKIP1FRAME - - - 122490.895 - - - -

2014-08-09 01:00:34 CEST comment server INFO 200 - TranscodingSession.updateBehindFilter[LamaOle/definst/live]: Video behind filter state change. New state: ALLFRAMESON - - - 122500.023 - - - -

2014-08-09 01:00:44 CEST comment server INFO 200 - TranscodingSession.updateBehindFilter[LamaOle/definst/live]: Video behind filter state change. New state: SKIP1FRAME - - - 122510.2 - - - -

2014-08-09 01:00:53 CEST comment server INFO 200 - TranscodingSession.updateBehindFilter[LamaOle/definst/live]: Video behind filter state change. New state: ALLFRAMESON - - - 122519.423 - - - -

7

These INFO messages “TranscodingSession.updateBehindFilter” typically indicate that Wowza Media Server is overworked and can’t process the packets in time. Typically occurs when CPU utilization or GPU utilization for acceleration is at maximum capacity or beyond workable threshold. Ensure you review the transcoder benchmarks as a basis for your available transcoding capacity.

8

Hi Stephan,

Thanks for the update. It may also be worthwhile passing your findings on to Datavideo to see if they have suggestions with regards to your setup, if you haven’t done that already.

Paul

9

Datavideo NVS-20 supports wowza server?

I was informed by my local Datavideo vendor that NVS-20 doesn’t support Wowza Server or even Akamai Server.