Blackmagic Forum

Hello everybody,
I have faced an common problem called playback lagging issue.
Playback is so much smoother on single viewer mode but when I turned on multicam, it's playback being too much slower.
If I choose 2x2 camera on multi-cam window, it's almost good enough playback but it can't play on 4X4.
How can I solve this issue?
I have to check each clip for editing.

See the number of playback frame is red on 4x4 default view.


This is good if I select 2x2 but I need to see all clips at a time.


Here is my pc config:


Thank you.

I can't see what your source media is. You might try transcoding to Cineform or DNxHR.

Could also be your drive just can't keep up with that may streams.

do you have enough bandwidth to play form teh drives? hows the CPU/GPu load when you dont have playback?

All the times I have had problem with multicam lagging is because of disk speed or transfer speed from the storage itself is to slow.

Cheers Jimmy

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waltervolpatto wrote:hows the CPU/GPu load when you dont have playback?

Valid question. However if you select «DaVinci Resolve -> Preferences.User -> UI Settings [x] Stop playback when a dropped frame is detected», that is announced as warning against performance issues, you'd find stops while CPU/GPU/Disk-load is way apart from limits.

Walter also suggested checking to see if there’s enough disk throughput. Does sound like a good idea since we’re talking about multiple streams of video.


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When I edit music videos with 15-20 angles, the only way to get smooth playback is to create proxies.

waltervolpatto wrote:do you have enough bandwidth to play form teh drives? hows the CPU/GPu load when you dont have playback?

Where I will see my GPU loading?

Jim Simon wrote:I can't see what your source media is. You might try transcoding to Cineform or DNxHR.

Could also be your drive just can't keep up with that may streams.

My source media is raw footage. It can play smoothly when I put maximum 3x3 on multicam. Is there any way to reduce playback resolution on multicam window also?

Jimmykarlsen wrote:All the times I have had problem with multicam lagging is because of disk speed or transfer speed from the storage itself is to slow.

Cheers Jimmy

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Did you tried from internal SSD with multicam project?

Joe Shapiro wrote:Walter also suggested checking to see if there’s enough disk throughput. Does sound like a good idea since we’re talking about multiple streams of video.


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I have enough disk space where caches are stored.

panos_mts wrote:When I edit music videos with 15-20 angles, the only way to get smooth playback is to create proxies.

Okey then maybe it's best solution. BTW I would like to ask an another thinks.
I can export my video .mp4 from my mac with audio codec AAC & depth with 24 but in my windows there is no options for AAC with 24 bit.
Can you tell me?

sabbir_ing wrote: Is there any way to reduce playback resolution

Maybe try this:

sabbir_ing wrote:

Joe Shapiro wrote:Walter also suggested checking to see if there’s enough disk throughput. Does sound like a good idea since we’re talking about multiple streams of video.

I have enough disk space where caches are stored.

It's not the space but rather the speed of the disks I'm suggesting as the problem.
If you have 2x2 playing smoothly then your disks can apparently handle that.
But 4x4 requires 4x more disk speed (throughput or bandwidth) than 2x2.

You can use, say, Black Magic Disk Speed Test to check the speed of your drives.
Here's what it looks like for my system disk on my 16" MBP M1:


As far as AAC goes, are you asking this because you want to make proxies, or for the eventual export? If it's for proxies, you shouldn't need to worry about sound bit depth because you'll make your final video from the original sources.

Reducing decode resolution may help if it’s not because of storage throughput, but computing power.
Some formats, like RedRAW from older cameras using wavelet profit more than cameras using DCT.
If that doesn’t help, it’s proxies.

Uli Plank wrote:Reducing decode resolution may help if it’s not because of storage throughput, but computing power.

Good point.

Thanks for suggesting. I didn't tried with proxies. My source footage on external hdd. I hope it makes slower.

HDDs are not only critical regarding throughput, but access times are very demanding for multi-cam.