logo

Live Production Software Forums


Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Options
Go to last post Go to first unread
bjustice  
#1 Posted : Tuesday, December 4, 2018 9:44:15 AM(UTC)
bjustice

Rank: Newbie

Groups: Registered
Joined: 11/29/2018(UTC)
Posts: 5

Hello everyone!

Disclaimer: I am an aerospace engineer and am out of my element here. Nonetheless, I need find a solution that will meet the following requirements:
- Record 30 3G-SDI streams
- all streams at 1080p60
- Only need to record for 500 seconds intervals
- Need to encode/save as MPEG-2 format

Here are my collected thoughts so far:

- Use VMIX multicorder software.
- Build 2 machines. Each machine will be responsible for recording up to 16 channels each
- Use BlackMagic Decklink Quad 2 capture cards. (2 cards per machine)
- Use BlackMagic MPEG-2 codec. (My vague understanding is that the capture cards perform the encoding rather than GPU or CPU?)
- Each capture card needs 8 gen2 PCIE lanes, so I need 16 PCIE lanes to CPU for each machine solely for these cards
- Use 2 Samsung Evo 960 NVMe in RAID 0 format. This will consume 4 PCIE lanes each. (If each stream consumes 100Mbits/second, then that's 1.6Gbits/second of required write speed to hard drive)
- motherboard/CPU with atleast 4 full PCIE slots with 8 dedicated PCIe lanes to each slot. (I haven't picked a board or CPU yet.)
- 32GB DDR4 RAM

Again, I only have a vague understanding of what I'm doing. I have a list of things that I don't quite understand yet:

- My understanding is that the BlackMagic capture cards have onboard FPGA that will encode the SDI input into MPEG-2 without having to pass the uncompressed video through the GPU or CPU. Is this true, or am I incorrect?
- My understanding is that the capture card will push the encoded MPEG-2 video to the CPU which then reroutes to the SSDs. As such, I shouldn't need very much GPU. Rather, I simply need to make sure that CPU can handle the PCIe lane number
- My understanding is that I can RAID 0 multiple SSDs in order to increase my write-rate. Looking at the numbers, it seems that two Samsung Evo 960 NVMEs at a write rate of 1900MB/s each should be plenty.

Any feedback on these thoughts would be greatly appreciated. It has been oddly difficult to find other people building similar machines.
Thanks for any input/thoughts!
IceStream  
#2 Posted : Tuesday, December 4, 2018 12:57:44 PM(UTC)
IceStream

Rank: Advanced Member

Groups: Registered
Joined: 3/7/2012(UTC)
Posts: 2,063
Man
Location: Canada

Thanks: 27 times
Was thanked: 360 time(s) in 342 post(s)
@ bjustice





I'm not saying it's impossible, but you might need more than two machines...
Just my thoughts.


Ice
bjustice  
#3 Posted : Tuesday, December 4, 2018 1:54:51 PM(UTC)
bjustice

Rank: Newbie

Groups: Registered
Joined: 11/29/2018(UTC)
Posts: 5

haha, it's very possible. And more machines is fine. But, ultimately, I guess that I don't have a good understanding of what resources that I need in order to capture/encode/record SDI video.

And I'm pretty fuzzy on what resources are available on the capture card FPGA. Can the capture card perform embedded encoding, or am I forced to push the video through the GPU for encoding?
bjustice  
#4 Posted : Tuesday, December 4, 2018 2:06:23 PM(UTC)
bjustice

Rank: Newbie

Groups: Registered
Joined: 11/29/2018(UTC)
Posts: 5

So far, this thread has been the most insightful:
https://forums.vmix.com/...aspx?g=posts&m=57091

This thread seems to indicate that:
- capturing 16 SDI streams at 1080p50 is within grasp of a modest machine. Maybe ~$10k
- The encoder settings will determine how much GPU is used. (This indicates to me that the video has to be passed though the GPU for encoding. I'm still curious if there are any encoder options that can be performed directly on the capture card FPGA without involving the GPU.)
- NDI/IP streams consume a ton of CPU resources in order to decode/record. As such, it's much better for me to try to perform all recording using SDI streams into capture cards.
zenvideo  
#5 Posted : Tuesday, December 4, 2018 6:27:16 PM(UTC)
zenvideo

Rank: Advanced Member

Groups: Registered
Joined: 5/13/2014(UTC)
Posts: 280
Man
United Kingdom
Location: Manchester, UK

Thanks: 1 times
Was thanked: 123 time(s) in 78 post(s)
I know this is a vMix forum, but software-wise you might be better off looking at something like Metus Ingest which is a dedicated multi-channel video recording application with lots of codec options, assuming you haven't seen it already.
bjustice  
#6 Posted : Wednesday, December 5, 2018 4:57:42 AM(UTC)
bjustice

Rank: Newbie

Groups: Registered
Joined: 11/29/2018(UTC)
Posts: 5

I have not seen Metus-Ingest. This seems like an interesting option.
Here is their hardware requirements page:
https://metuskb.atlassia...equirements+-+The+Latest

"The hardware requirement of Metus Ingest depends on many variables, such as number of inputs, target format, frame rate etc…
Please contact our sales team for Ingest hardware recommendation that would meet your need."

So, I'll contact them and see what they suggest
JoseL  
#7 Posted : Wednesday, December 5, 2018 6:31:41 AM(UTC)
JoseL

Rank: Advanced Member

Groups: Registered
Joined: 4/15/2018(UTC)
Posts: 40
Man
Location: Spain

Thanks: 6 times
Was thanked: 7 time(s) in 4 post(s)
Metus for 30 cameras?, really?, only licenses will be more expensive than hardware. I think vmix is more eficient than metus, at least with mp4.
I didn’t test mpeg2, but mp4 with p5000 is near limit or maybe over limit with 16 sdi3g inputs.
I think the best way is 3 machines. No problem to get 10x sdi 3g with p5000 to mp4. But i didn’t test mpeg2.
Users browsing this topic
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.