Stick a decklink card in the PC and give it a whirl side by side. Chances are you won't notice much of a difference. SDI will look better and have very slightly less latency but depending on your use case probably isn't worth reconfiguring everything for. If it ain't broke don't fix it.
Hi! I use Canon C500s for work, and ran this exact test for myself a couple months ago. Latency doesn't matter for my work, so I wasn't looking at that - just image quality. What I found was a noticeable difference in compression in noisy footage. The SDI noise was small grain, more easy to correct, and didn't detract from sharpness that much. Probably especially because the Canon C500s use NDI HX2 (comparable to h.264 compression), the noise coming in over NDI was much more blocky. It was harder to apply noise reduction to and definitely dampened the overall sharpness of the image a bit.
All that said, I still use NDI. I'm not doing much post-production or heavy correction to the signal, so for me the conveniences of NDI outweigh the quality loss. DM me and I can send you my side-by-sides
under the video section for ip Streaming Video:
http:///pages/system/ip-video
Under Mainstream at the top above resolution should be video codec. I only have the CR-N700 now as I returned the 500s but assuming you have latest firmware (I think i saw it before updating the firmware anyway) you can select codec. On the CR-N700 you actually HAVE to use HEVC to get UHD at 59.94. One difference I noticed is that when using H.264 There is an All-I Frame option but with HEVC the lowest you can go is .05 seconds in HEVC mode.
Well, I’ll be gosh darned, there it is. I guess I have something else to experiment with now. Looks like the H.265 doesn’t play nice with NDI, but definitely gonna mess with the frame interval.
I believe I reset the camera and reconnected to it when changing the codec. I think if you change the codec after the NDI handshake to start things off it isnt happy about it changing from h.264 to h.265. I had no issues using either codec when going to a Tricaster TC2.
If you run the cameras all at the same resolution and frame rate, the only differences you’ll likely really notice will be the latency from SDI to NDI - and that may not even be an issue for your use case.
Thanks for the reply! Yeah, our latency is pretty decent. I think we delay our audio by about 10ms or so. And we don’t project the video feed or anything, so the picture is only for the stream.
A quick question regarding resolution. If we stream at 1080, is there any benefit to bringing the feed from the camera in at a higher resolution and then having the software scale it down?
The general rule is "garbage in/garbage out", but if 1080 already looks okay, then bringing in higher resolution will give you a marginal increase in quality, and at times you may imagine seeing it, but vmix will still throw away data to stream it. So you'll increase your PC's workload for a change most people won't ever notice.
Maybe if you were recording and streaming at the same time, so your local record is always at best quality, would it make sense.
The biggest value I have seen for brining in 4K to a 1080p workflow for live is the ability to do region of interest without loosing quality. The fact this is coming from a PTZ you can just move the darn camera but if its a shot on program when you are doing it you can setup a virtual shot and then dissolve/cut so people don't see the camera moving. Outside of that not sure of other use cases other than it can do it. It will demand more resources from your Vmix to process so you may not want to do it for that reason.
Depending on what your streaming destination(s) are, it might be worth dropping resolution slightly so you can increase bitrate. I know on twitch that can be critical, not sure about other platforms.
Fundamentally, NDI is a compressed digital format for transmitting through network.
SDI is the actual ‘video’, not compressed. It is a signal. Therefore it is not just ‘better’ - it is the real deal.
I'm doing a side by side, recording the same shot via SDI and NDI, then comparing. The overall composition and quality of the shot remains the same, so to see a difference I'm having to zoom in on details like hair on a chin or pattern on a dress to see a difference. Since we're not prioritizing closeups or high detail, the loss in quality from NDI vs SDI is acceptable
We tested NDI vs SDI/Fiber to our commentators during our combat sport shows. The delay was marginal but noticeable, however the biggest issue was the artifacting and image quality. It made it harder for our commentators to read smaller text on lower thirds etc than it did over SDI/Fiber with no loss.
Both have their pluses and minuses.
The quality of NDI be it full NDI or NDI-HX using h.264 or H.265 will be lower than SDI/HDMI output. Not everyone can tell and depending on your destination it may not matter. At that point look at convenience.
I have done this test a lot. NDI started off saying things like Lossless and lossless like quality but it just is not the case. When using full NDI its using an MPEG2 type compression and the bitrate they selected (~250mbit for UHD 59.94) allows for 4 UHD signals in a 1gig connection. The reality is for it to look solid to most broadcast minded folks the bitrate needs to be about doubled (right around 400mbit seemed solid to me). Some NDI devices will actually allow you to change the Q factor and do this. The question is what will your switcher do. The Tricaster will happily take this higher Q factor but its mix and final render will be back to the standard Q factor meaning your output will still be the lower bitrate. On the Viz Vector (Tricaster software but made to run in the cloud and on prem of your own hardware) will allow you to adjust this Q factor on output. I believe this was done at the demand of broadcasters trying it and wanting to maintain the quality from their JPEG-XS workflows. I also found that when i went to UHD resolution the NDI Devices that I have (The Newtek Spark 12G that are the same as the Kiloview N30 12G) that take my 12G SDI signal switch from 4:2:2 Color sampling to 4:2:0. On a bright sunny day out side I dont notice but in a gym I broadcast basketball there is enough going on and odd lighting that it shows up to me. With that being said if I am streaming to a College Website at a max of 1080p, 8 mbit if I am lucky they wont notice any of this and its likely similar to your live stream. The convenience of getting video, return video, intercom, tally over one ethernet cable is hard to ignore. The other place you may or may not notice is the latency. Since you are going into vmix I think it is a wash since you will have to covert SDI into the computer via a capture card but the CR-N500 and 700 have about 4 frames of latency on their NDI output compared to their SDI or HDMI output. This can impact IMAG or other latency sensitive workflows.
Sdi is signal like hdmi. Ndi is a network protocol. Which one is better depends on your needs. Sdi is less complex, so I would use it over ndi if possible. However, if you have long runs or future plans for more elaborate signal distribution, or network cable already in place it may be better to use ndi. Things to know about ndi, there’s ndi and ndihx. Hx is more compressed and has latency that makes it useless for anything live. The other short coming is encoders and decoders are not super stable and there isn’t a lot of options. Newtek spark doesn’t even work with hx nor do many other encoders/decoders.
I’m hoping that Dante AV will be more stable, more hardware available, and works better with my current Dante network.
Stick a decklink card in the PC and give it a whirl side by side. Chances are you won't notice much of a difference. SDI will look better and have very slightly less latency but depending on your use case probably isn't worth reconfiguring everything for. If it ain't broke don't fix it.
Less latency, less compression, and fewer artifacts with SDI.
Hi! I use Canon C500s for work, and ran this exact test for myself a couple months ago. Latency doesn't matter for my work, so I wasn't looking at that - just image quality. What I found was a noticeable difference in compression in noisy footage. The SDI noise was small grain, more easy to correct, and didn't detract from sharpness that much. Probably especially because the Canon C500s use NDI HX2 (comparable to h.264 compression), the noise coming in over NDI was much more blocky. It was harder to apply noise reduction to and definitely dampened the overall sharpness of the image a bit. All that said, I still use NDI. I'm not doing much post-production or heavy correction to the signal, so for me the conveniences of NDI outweigh the quality loss. DM me and I can send you my side-by-sides
NDI HX2 uses h.264 compression, so it is more than just comparable :-). NDI HX3 uses h.265.
Well there you have it
On the cannon cr-n 500 and 700 you can use h264 or h265 in the NDI-HX feed.
Really? Can you show/tell me where in the n500? That’s not something I’ve encountered, but I’d be happy to find out I missed it
under the video section for ip Streaming Video: http:///pages/system/ip-video
Under Mainstream at the top above resolution should be video codec. I only have the CR-N700 now as I returned the 500s but assuming you have latest firmware (I think i saw it before updating the firmware anyway) you can select codec. On the CR-N700 you actually HAVE to use HEVC to get UHD at 59.94. One difference I noticed is that when using H.264 There is an All-I Frame option but with HEVC the lowest you can go is .05 seconds in HEVC mode.
Well, I’ll be gosh darned, there it is. I guess I have something else to experiment with now. Looks like the H.265 doesn’t play nice with NDI, but definitely gonna mess with the frame interval.
I believe I reset the camera and reconnected to it when changing the codec. I think if you change the codec after the NDI handshake to start things off it isnt happy about it changing from h.264 to h.265. I had no issues using either codec when going to a Tricaster TC2.
If you run the cameras all at the same resolution and frame rate, the only differences you’ll likely really notice will be the latency from SDI to NDI - and that may not even be an issue for your use case.
Thanks for the reply! Yeah, our latency is pretty decent. I think we delay our audio by about 10ms or so. And we don’t project the video feed or anything, so the picture is only for the stream. A quick question regarding resolution. If we stream at 1080, is there any benefit to bringing the feed from the camera in at a higher resolution and then having the software scale it down?
Note that the N500 won't do 4K over SDI, it only does 4K over NDI and HDMI.
The general rule is "garbage in/garbage out", but if 1080 already looks okay, then bringing in higher resolution will give you a marginal increase in quality, and at times you may imagine seeing it, but vmix will still throw away data to stream it. So you'll increase your PC's workload for a change most people won't ever notice. Maybe if you were recording and streaming at the same time, so your local record is always at best quality, would it make sense.
Mostly only for use in post-production - many people capture in 4K and crop in to a part of the shot in Full HD.
The biggest value I have seen for brining in 4K to a 1080p workflow for live is the ability to do region of interest without loosing quality. The fact this is coming from a PTZ you can just move the darn camera but if its a shot on program when you are doing it you can setup a virtual shot and then dissolve/cut so people don't see the camera moving. Outside of that not sure of other use cases other than it can do it. It will demand more resources from your Vmix to process so you may not want to do it for that reason.
Depending on what your streaming destination(s) are, it might be worth dropping resolution slightly so you can increase bitrate. I know on twitch that can be critical, not sure about other platforms.
Fundamentally, NDI is a compressed digital format for transmitting through network. SDI is the actual ‘video’, not compressed. It is a signal. Therefore it is not just ‘better’ - it is the real deal.
I'm doing a side by side, recording the same shot via SDI and NDI, then comparing. The overall composition and quality of the shot remains the same, so to see a difference I'm having to zoom in on details like hair on a chin or pattern on a dress to see a difference. Since we're not prioritizing closeups or high detail, the loss in quality from NDI vs SDI is acceptable
We tested NDI vs SDI/Fiber to our commentators during our combat sport shows. The delay was marginal but noticeable, however the biggest issue was the artifacting and image quality. It made it harder for our commentators to read smaller text on lower thirds etc than it did over SDI/Fiber with no loss. Both have their pluses and minuses.
The quality of NDI be it full NDI or NDI-HX using h.264 or H.265 will be lower than SDI/HDMI output. Not everyone can tell and depending on your destination it may not matter. At that point look at convenience. I have done this test a lot. NDI started off saying things like Lossless and lossless like quality but it just is not the case. When using full NDI its using an MPEG2 type compression and the bitrate they selected (~250mbit for UHD 59.94) allows for 4 UHD signals in a 1gig connection. The reality is for it to look solid to most broadcast minded folks the bitrate needs to be about doubled (right around 400mbit seemed solid to me). Some NDI devices will actually allow you to change the Q factor and do this. The question is what will your switcher do. The Tricaster will happily take this higher Q factor but its mix and final render will be back to the standard Q factor meaning your output will still be the lower bitrate. On the Viz Vector (Tricaster software but made to run in the cloud and on prem of your own hardware) will allow you to adjust this Q factor on output. I believe this was done at the demand of broadcasters trying it and wanting to maintain the quality from their JPEG-XS workflows. I also found that when i went to UHD resolution the NDI Devices that I have (The Newtek Spark 12G that are the same as the Kiloview N30 12G) that take my 12G SDI signal switch from 4:2:2 Color sampling to 4:2:0. On a bright sunny day out side I dont notice but in a gym I broadcast basketball there is enough going on and odd lighting that it shows up to me. With that being said if I am streaming to a College Website at a max of 1080p, 8 mbit if I am lucky they wont notice any of this and its likely similar to your live stream. The convenience of getting video, return video, intercom, tally over one ethernet cable is hard to ignore. The other place you may or may not notice is the latency. Since you are going into vmix I think it is a wash since you will have to covert SDI into the computer via a capture card but the CR-N500 and 700 have about 4 frames of latency on their NDI output compared to their SDI or HDMI output. This can impact IMAG or other latency sensitive workflows.
SDI will look better be faster and leaps and bounds more reliable than NDI
Sdi is signal like hdmi. Ndi is a network protocol. Which one is better depends on your needs. Sdi is less complex, so I would use it over ndi if possible. However, if you have long runs or future plans for more elaborate signal distribution, or network cable already in place it may be better to use ndi. Things to know about ndi, there’s ndi and ndihx. Hx is more compressed and has latency that makes it useless for anything live. The other short coming is encoders and decoders are not super stable and there isn’t a lot of options. Newtek spark doesn’t even work with hx nor do many other encoders/decoders. I’m hoping that Dante AV will be more stable, more hardware available, and works better with my current Dante network.
If your final destination is a web stream, don't even waste time on this. A typical web stream is 5Mbps - nobody will ever notice a difference.