Issue: When Instant Replay is recording, playback of replay events is at very poor quality. Sound and video stutters. When IR isn't recording, playback from the previous Replay recording is fine.

Is this a configuration issue, or do I need to upgrade something?

My hardware:

Dual Xeon e5-2630v2 (12 cores @2.6Ghz)
16 GB RAM
Radeon R7 360 2GB gfx
SSD1: OS only
SSD2: vMix app + input source (screen graphics etc are on this SSD)
SSD3: Dedicated Replay (only IR written or read from here)

- The SSDs are all on their own/separate buses.
- Instant Replay is capturing only 1 camera (a BM Decklink SDI input) @ 50Mbps
- Project is 1080p59.94

For completeness, when I play back from IR, I have a PiP of the current live action overlayed on the Output as seen here:

Minimum requirements for Instant Replay (from the vMix User Guide)

1 Channel HD = NVIDIA 950 1GB

4 Channels HD = NVIDIA 960 2GB

vMix is optimized to use NVIDIA cards. Do you have one available to install in your system?

Thanks for the replies... yeh comparing gtx960 with the r7 I have and the gtx960 looks to have 50% more grunt. Plus I have a 3440x1440 monitor plugged into it.

I've got a gtx960 with 4GB RAM in another PC I will pull out and test with. Will report back once tested.

Just curious... what other software is running besides vMix?

- Tom

Hi Everyone,

I wanted to piggyback off of this forum posting, because I am basically seeing the same problem on a new rig I started building this week. My first Instant Replay rig actually... I started using vMix in 2013 and love it to death, but never seemed to have a wish to use the Instant Replay functions until now...

Similarly to chrisis, I really only start to notice a problem when recording and playing back simultaneously in a 2-camera instant replay scenario. My best guess right now is that my storage is somehow being a bottleneck, although I have a very fast SSD dedicated to Instant Replay storage. I also managed to find a reproducable Replay UI interface bug that I will share later in this post.

My hardware is as follows:
Asus Z10PA-D8 server motherboard
2x Xeon E5-2620v4 quad core @ 2.10GHz
Intel SSD 750 Series SSDPEDMW400G4R5 400GB PCI-Express 3.0 NVM disk (for replay only)
NVIDIA GTX 750 Ti
Cameras being recorded are 2 NDI network sources inside my LAN
Project & Replay settings are 1920x1080p 59.94
vMix 21.0.0.56 x64

My total CPU usage is ~30% when running vMix with the replay recording & playing. Render times hover between 4-12ms. In the statistics window, the "Source Dropped" climbs about 5 frames per second. I have relay channel A & B set to camera 1, and if I switch channel B to camera 2, the stuttering/dropped frames gets worse. I've already run the vMix Diagnostics tool and it found no issues with running programs.



I was considering buying a GTX 1080 card, but given the results by chrisis, I feel like I want to hold off for now since my render times aren't high and thus don't feel that would help this problem.

I'm definitely hoping to find a solution to the dropped frames when playing out, I feel like this disk is plenty fast.

---

Additionally, a separate issue mentioned above, I found some funky behavior when adding the 2 NDI cameras to the replay settings screen. If I add them and specify 25Mbps recording, the 2 replay inputs are created successfully, but when I hit record I get this error...



And the instant replay controller shows no input information...



If I go back to the Replay Settings and change it to 100Mbps (for example), then the input information appears and the recording begins properly. I can even change it back to 25Mbps at this point and no recording error is seen.



Thanks to those who have replied to my earlier threads, and thanks Martin for continuing to update and support a great product.

Hi Martin,

Thanks for the information, I didn't realize the replay threads were single core/threaded, and figured the 32 cores would be sufficient to have everything run smoothly.

Thanks for your time.

In double checking the vMix specs for Instant Replay (Ruby - 8 Cameras with 4 Camera Instant Replay), the specs do not identify whether the frame rate is 25/30fps or 50/60fps. Big difference!

- Tom

Onboard RAID. Blackmagic Disk Speed test shows about 700mbps write 900mbps read. Stinger is on C:\ drive.

Total inputs is 50. Graphics card specs are posted earlier by me. We havr that High Input Prrformance mode enabled. Broadcasting a game now and in 2nd quarter. Having same issue. Rander times 20-40ms with replay. Is the RAM too slow as someone suggested earlier? I need to know what to purchase to fix our issue. Here are screenshots of our system performance right now:

After lots of troubleshooting I have resolved the issue! The image sequences is what caused the high render times. We have 3.5GB worth of PNG images. The quality was way to high for our system to handle. We converted them to quicktime videos with alpha channel. Also changed from 59.94fps to 29.97fps since we broadcast and record at 29.97fps. This allowed the system to recover from high render times quicker. Replay is still recorded at 59.94fps so that we can have smooth replay. Thank You Martin for for the help! (Sick beard bruh!)