802.11 app Framework VLC communication problem

[Marwanjk]

Hi all, I'm working with the 802.11 App Framework and I have problems with VLC streaming, the data rate never surpass the 400Kbs. I have the same problem with the LTE App Framework. I don't have problems with PN generator.
I'm working with a Ettus X310 with SBX daughterboard.
Another interest data: When I use a traffic generator (like Ostinato) the data rate is lower than the one I obtain with the PN generator.
My question is if there is some extra configuration to make stream video with this App Framework.
Thks

[joergho]

Hi! The data rate that you can reach should be independent of the data source, i.e. it does not matter if the data is provided by the "PN Data" generator or coming from UDP. However, if you see issues with the throughput when using UDP, then I recommend that you use a traffic generator first to track down the root problem before you try the video streaming. If you set the size and rate of the data packets to the same value as the "PN Data" source, you should get the same throughput over UDP as when using the "PN Data" generator.

[tcap]

Hello Marwanjk,

I am capable of achieving about 888kb/s with the PN and about 1088kb/s with the UDP. 

Can you stream any video or are you just getting a black screen?

Regards, 

[Marwanjk]

Hi tcap, I transmit video with a bitrate lower than 400kbs. A upper bitrate generate a non continuos transmission.  

[tcap]

Hello Marwanjk,

Have you modified the Framework at all or are you just using the default project?
How are you controlling the bitrate of VLC?
What commands are you using to run VLC?
Are you using a loopback?
What is the size of your PN Data Packet in comparison to your VLC data packet?
Do you know if you have a strong firewall that could be slowing down your UDP broadcast?

Regards,

[Marwanjk]

Hi tcap,
I started to make modifications for improve the performances. I'm using the internal loopback.
I eliminated the wait time to increase the Host Loop Update.
I eliminated the queue max size in the transmit queue and the receive queue in the host init.
with all of this modifications i have a better performances. I'm thinking that the problems is in the reader of the UDP packet i send to the framework. because is the same problem with the traffic generator.
The VLC player works well using two computers in the network with the same parameters and in the same computer. I use the graphic panel to the emission (UDP legacy).
the packet length from the VLC is arpox 1029, I attach a image of the energy for loop of the PN generator with the same packet length and with the VLC.

[tcap]

Hello Marwanjk,

I am sorry about my calculations earlier.  The throughput that I am getting is about 1.9Mbit/s to 2Mbit/s on PN and between 900kbit/s and 1.8Mbit/s on UDP.  This variability is is most likely due to the UDP port processing and the speed calculation is from the Basic Tab Receive plot.  I am using an unmodified version of the 802.11 framework, with a packet size of 1316.  For the UDP transmission, I am using the attached batch file to launch VLC.

I agree with joergho.  I think that we should troubleshoot this using PN mode to ensure that we can achieve roughly about 2Mbit/s and then move to the traffic generator or VLC.  

Do you have a lot of parallel applications running that could be slowing down your processing speed?  

What is your CPU usage when you are running the PN generator?

Does your computer have a strong firewall that could be impeding UDP transmission?

Regards, 

[Marwanjk]

Hit tcap,
with the same configuration I obtained the same results, but not with VLC ( more o less 400 Kbit/s), with a traffic generator the same. Changing the Host Loop Update Rate time to 0, up to 8-9 Mbit/s.
I'm not using firewall or antivirus.
The Cpu usage in PN mode is between 81-88%.
I created a test program to only receive from a UDP port and transmit to another but is the same problem with VLC.
I was thinking to chunk a file in parts and transmit this directly (or something that works like PN mode). I start to think that the problems is in the UDP reader.
Regards

[tcap]

Hello Marwanjk,

If your CPU Usage is 81-88% on PN Mode, which only requires a locally hosted random number generator, what is your CPU usage when you are running VLC? VLC, in theory, should be much more computationally intense, because it requires video streaming to UDP and from UDP.

So just to be clear about your test program, you have the same problem when you just have LabVIEW Communications read the UDP port and immediately output the packet to another UDP port? If this is the case, I think that there could be a problem with your computer or how you have VLC set up.

Can you please try to run the GVI that I attached below and run the attached batch script? This should allow use to isolate the issue away from the 802.11 Framework and the USRP RIO. When you run this program, are you experiencing the same problem?

What version of VLC are you using?

Regards,

[Marwanjk]

Thanks tcap
using your test program I was having the same problems, but I start to use another computer on the LAN to transmit the in VLC, and now I obtain the same results you have (a data rate 800-1.1 Mbit/s).
I'm using the VLC 2.2.1 (the last version).
The processor when I use the same computer for the 2 things and the 802.11 is in the order of 84-98%. When I use the other computer to transmit is on 15%.

Regards