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TheMissingLink2
02-15-2018, 08:38 PM
I have two laptops. The older one is a 1080 display and the newer one is a 4k display. When I use scan converter to send the older 1080 laptop screen to Studio Monitor on the newer 4k laptop, everything appears okay and it transfers about 120mbps of activity over the network. When I use scan converter to send the newer 4k laptop screen to Studio Monitor on the older 1080 laptop, the video stutters and it is only transferring about 20mbps over the network. I have scan converter on high frame rate (although I've tried both just in case) and Studio Monitor is not set to Low Bandwidth. Is there anything else I should try to get it to work properly? The newer 4k display laptop is running the latest version of the NDI tools. The older 1080 display laptop is running the previous version (they are both listed as version 3.0 but the one is slightly older) since I tried installing the newest version and Studio Monitor always crashes when loading. I'm not sure if this would make a difference, but the newer 4k laptop has a dual GPU (Nvidia and Intel) but in the Nvidia control panel I have it set to prefer the Nvidia. I've also tried changing the display scaling but that doesn't seem to make a difference on this issue.

Also, I notice more data is transferred over the network with sending a specific program over Scan Converter instead of sending the desktop (I tested using the exact same video being played in Chrome). Is that normal?

Thanks!

TheMissingLink2
02-16-2018, 03:31 AM
As an update on this, it appears it is something in the latest version of NDI Scan Converter that is causing this issue. On my newer 4k laptop, I removed the current NDI tools and installed the previous version (the same one that is on my older 1080 laptop) and that version of Scan Converter works okay. I was incorrect in the above post where I mentioned the difference in network activity that I notice since I wasn't comparing the same source. I am actually getting about half the network activity in the new version vs. the old version of Scan Converter. Is there any known issue with the latest NDI Scan Converter or is there something I might be doing wrong? Would the fact that I was using an older version of NDI Tools on my older 1080 laptop (since Studio Monitor would crash anytime I opened it when I upgraded to the latest version) and the newest version on my newer 4k laptop possibly have something to do with it? I confirmed that the VLC plugin doesn't seem to have the same issue. I've gone back and forth a couple of times between versions and it is happening consistently without my making any other changes.

Thanks!

ACross
02-16-2018, 04:10 PM
The difference between the older version of Scan Converter and the new one is that there where reports about the quality of the scaling in the previous version and so the new one uses higher quality GPU scaling in order to capture the screen. The reason why this is potentially causing you problems is that a 4K display involves transferring 3840x2160x4 = 33Mb of data per frame. If you have 60Hz enabled, this is 2Gb/s of data that needs to be transferred across the PCIe bus and while you have a dedicated GPU this is still a lot of bandwidth for a laptop ... and once it has been transferred it needs to then be scaled and compressed. It is quite possibly that if you have a dual GPU system that there is also some efficiency related to that and how data transfer is going to happen. Regardless, there is something super secret that we are working on that we will contact you off-line with that I cannot yet talk about publicly.

Andrew

ps. I am more worried about the fact that Studio Monitor crashed for you, QA will contact you on that.

TheMissingLink2
02-17-2018, 01:46 AM
The difference between the older version of Scan Converter and the new one is that there where reports about the quality of the scaling in the previous version and so the new one uses higher quality GPU scaling in order to capture the screen. The reason why this is potentially causing you problems is that a 4K display involves transferring 3840x2160x4 = 33Mb of data per frame. If you have 60Hz enabled, this is 2Gb/s of data that needs to be transferred across the PCIe bus and while you have a dedicated GPU this is still a lot of bandwidth for a laptop ... and once it has been transferred it needs to then be scaled and compressed. It is quite possibly that if you have a dual GPU system that there is also some efficiency related to that and how data transfer is going to happen. Regardless, there is something super secret that we are working on that we will contact you off-line with that I cannot yet talk about publicly.

Andrew

ps. I am more worried about the fact that Studio Monitor crashed for you, QA will contact you on that.

Hi Andrew. I received the info from Tech Support. Thanks for the follow up on this.

olepogam
02-20-2018, 09:02 AM
Hello,
I have similar issues trying to send a 4K display to the Tricaster using NDI Scan Converter : it does not seem to cope correctly, the video looks like 3fps or less ... We have benchmarked the network between both of them, and it supports its full GB. With a 1080p display, everything runs smoothly.
Do you have a solution ? Is there a possibility to downscale before sending through NDI Scan Converter ? Basically, in your opinion, who's the culprit ?
Olivier

ACross
02-21-2018, 09:06 AM
Hello,
I have similar issues trying to send a 4K display to the Tricaster using NDI Scan Converter : it does not seem to cope correctly, the video looks like 3fps or less ... We have benchmarked the network between both of them, and it supports its full GB. With a 1080p display, everything runs smoothly.
Do you have a solution ? Is there a possibility to downscale before sending through NDI Scan Converter ? Basically, in your opinion, who's the culprit ?
Olivier

Oliver,

We would already downscale to 1080p when running in this configuration, but the problem is that we rely on the GPU to download to system memory while scaling and some older GPUs or GPUs on a slower PCIe bus have this significantly impact performance. The problem is not the network bandwidth that is largely immaterial when using Scan Converter because it can easily get pretty good compression due to the nature of the screen content. if you email [email protected] we might be able to put make space on a beta for something new, but you are not going to have to wait long anyway either way.

Andrew

JPulera
02-21-2018, 09:21 AM
Question to OP - I haven't used a 4k laptop, but can't you go into Display Settings and change to 1920x1080, so that you are not trying to compress 4K to NDI? Unless you truly need 4K resolution for whatever you are doing.

Thanks

Jeff

TheMissingLink2
02-22-2018, 02:39 AM
Question to OP - I haven't used a 4k laptop, but can't you go into Display Settings and change to 1920x1080, so that you are not trying to compress 4K to NDI? Unless you truly need 4K resolution for whatever you are doing.

Thanks

Jeff

Hi Jeff,

Newtek was able to offer me a different solution that works great but I decided to give this a try anyway. Changing the resolution to 1920x1080 does seem to eliminate the problem. Thanks for the suggestion.

I also want to say thanks to Andrew and everyone at Newtek that assisted me with the problems I had with Scan Converter and Studio Monitor. They were able to provide me with a solution to both problems. I was really impressed with how quickly they responded to this.

TheMissingLink2
03-01-2018, 02:59 AM
I've been playing around with the NDI Tools in order to see the quality of NDI. I have noticed that using Scan Converter or the VLC plugin seems to result in the video not being completely smooth. I've tested this on my old and new laptop. At first I thought it was possibly a network issue, so I ordered a new switch to try, but then I realized I could use Scan Converter or the VLC plugin on the same computer that I'm using NDI Monitor to rule out the network and I notice the same thing. I even screen captured the video and went frame by frame through it and noticed there would be pauses for a single frame at different points. Sometimes the video would speed up in the frame right before the pause (like it skipped a frame and then it would pause to catch up).

I was wondering if Scan Converter/the VLC plugin is not the best way to test NDI when trying to see how smooth it is? Does the Tricaster converting sources to NDI do it in a different manner where it avoids things like I am seeing? Overall I think the quality is very good aside from these single frame pauses that I'm noticing (it doesn't happen on the majority of frames, but happens enough to notice it).

I've also noticed that Isocorder (the free version) on my new laptop seems to have a lot more paused frames when I'm watching it compared to NDI Monitor. Has anyone else noticed that?

Thanks!

TheMissingLink2
03-01-2018, 03:21 AM
I decided to screen capture the original source that I was playing in VLC and I do notice some pauses there as well so it is possible VLC is inserting some pauses. I tried screen capturing the source earlier, but didn't notice any glitches then, but in NDI Monitor it seems to be more consistent. I know the video is not the problem since it happens at different times in the video. I have watched the video playing in VLC as well as in NDI Monitor, and the glitches in NDI Monitor have been more apparent to me (although that may only be because I was looking more closely for them). I would still like to know if the Tricaster/NC1 are better at converting sources to NDI without paused frames compared to Scan Converter/VLC plugin and also what may be causing Isocorder to have more paused frames than I am seeing in NDI Monitor.

Thanks!

kanep
03-01-2018, 09:26 AM
I wouldn't use NDI Scan Converter as the reference, grabbing the screen depends greatly on the performance on the computer in question along with it's graphics card. It possible to get full frame rate using this tool with a system that has the performance to do so.

I use the VLC Player NDI plug-in all the time and have had good success with it. However, I've not gone back and looked frame by frame to see if they are all there, but I'm not noticing pauses or drops in the video when I use it. Also what frame rate are you trying to examine? 30fps? 60fps?

The other possibility is what is the computer you are running these tools on? Can it keep up with what NDI is trying to to? Not just on the source side (NDI Scan Conveter/VLC Player) but also the receiving side (NDI Studio Monitor). Is the system in question 64-bit or 32-bit? 64-bit is highly recommended for NDI on both the operating system and applications (there is a 64-bit version of VLC).

The NDI used between NDI Tools and what is in the TriCaster is the same. However the TriCaster has very powerful GPU and CPU capabilities, while NDI is very efficient, it is still possible to have a system that doesn't have the performance to keep up with that real-time performance it needs.

TheMissingLink2
03-01-2018, 11:46 AM
The older laptop I've tried it on has an Intel Core I7-Q840 CPU with an NVIDIA GeForce GTX 460M graphics card. The newer laptop I've tried it on has an Intel Core I7-6700HQ CPU with an NVIDIA GeForce GTX 980M and an Intel HD Graphics 530 graphics card. On the new laptop I have it set to prefer the NVIDIA graphics card at all times, but I don't believe it is possible to actually disable the Intel Graphics which I guess could be causing problems. Both laptops are 64 bit and I have the 64 bit version of VLC installed. The videos I've tried are 1080P, 30 frames. I would think these would be powerful enough, especially my newer laptop, but is it possible that laptops in general are not powerful enough to handle NDI? As I said, I have been able to get good results, just not perfect when examined closely.

Thanks!

TheMissingLink2
03-03-2018, 03:37 AM
After playing around with this some more, it does appear that I'm getting paused frames in the source, whether it is VLC or a Youtube video, so it is likely something with my laptops processing 1080p video that cause the paused frames. It is not noticeable when watching normally, but since I was watching closely (and even going frame by frame through screen captures) to monitor the quality of NDI, it stood out to me.

I also figured out why I was getting worse quality with Isocorder than what I was seeing in Studio Monitor. Apparently I was recording the desktop in Isocorder instead of the actual program, while playing the actual program in Studio Monitor. Capturing the desktop seems to not get as good quality as capturing the actual program. I was already aware of that, but what I think happened is I would be screen capturing a specific program in Isocorder originally and then I would close that program to capture a different program, then Isocorder would switch to the desktop capture and I didn't realize it.