In obs I'm recording to mkv then automaticallly convert to mp4. My keyframe interval is 1.

My average fps for the UltraHD looped region on the sample is 10. The average for the whole video is 17. My Render time was 01m:16.80s

Sounds good on OBS settings.

That's worse than expected for a system of this caliber. NVDEC may be a variable as I never use it. Do you get a similar playback and render time with hardware decoding set to off in preferences/ file io? You have cores to spare!

@wedge
- Show us the MediaInfo of the used source video following this tutorial :https://www.vegascreativesoftware.info/us/forum/faq-how-to-post-mediainfo-and-vegas-pro-file-properties--104561/
- Which driverversion is installed for the Nvidia RTX 2080ti?

@RogerS With hardware decoding off my fps would be arounf 20-40. With it on it woul be 60fps for 3 seconds the go to 8-30 for 3 seconds. Vegas is fully using 2 cores at 5.80ghz and about 20% usage on 2 more. Vegas 14 can run this project normally. My intel 5960x w/ a GTX 1080 also can with any version of vegas

@j-v I have the GeForce Game Ready Driver 526.98. Released on 11/16/2022. There maybe a problem with the media coming from obs. I just tested out a nvidia shadowplay 4k recording and the preview ran at 59.940 fps with some drops to 58 or 59.7

General
Complete name                            : G:\OBS\2022-11-29 10-37-31.mp4
Format                                   : MPEG-4
Format profile                           : Base Media
Codec ID                                 : isom (isom/iso2/avc1/mp41)
File size                                : 50.2 GiB
Duration                                 : 1 h 53 min
Overall bit rate mode                    : Variable
Overall bit rate                         : 63.3 Mb/s
Writing application                      : Lavf58.29.100

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L5.2
Format settings                          : CABAC / 2 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 2 frames
Format settings, GOP                     : M=3, N=60
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 1 h 53 min
Bit rate mode                            : Variable
Bit rate                                 : 63.0 Mb/s
Maximum bit rate                         : 100.0 Mb/s
Width                                    : 3 840 pixels
Height                                   : 2 160 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Variable
Frame rate                               : 60.000 FPS
Minimum frame rate                       : 58.824 FPS
Maximum frame rate                       : 62.500 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.127
Stream size                              : 49.9 GiB (99%)
Color range                              : Full
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.470 System B/G
Codec configuration box                  : avcC

Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 1 h 53 min
Bit rate mode                            : Constant
Bit rate                                 : 319 kb/s
Channel(s)                               : 2 channels
Channel layout                           : L R
Sampling rate                            : 44.1 kHz
Frame rate                               : 43.066 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 259 MiB (0%)
Title                                    : Track1
Default                                  : Yes
Alternate group                          : 1

@wedge Because you know your Vegas's and your computers so well you are in a good position to test this idea that Remuxing CFR MKV to MP4 causes your Vegas20 lag problems. Although not sensible to do, for a test, could you keep your settings identical, but instead of recording to mkv record direct to mp4. Does that change the way VP20 plays back your OBS files?

"With hardware decoding off my fps would be arounf 20-40. With it on it woul be 60fps for 3 seconds the go to 8-30 for 3 seconds."

So there's an issue with NVIDIA decoding and the media for your project. Does turning it off change the render and preview time for the sample project as well?

The 4k sample render with with hardware decoding off was 01m:13.53s. My average fps for the clip was about 1 or 2 fps higher.

@j-v The problem seems to be the variable frame rate at high resolutions. OBS remux is changing cfr to vfr. Probably a bug. I tested recording straight to mp4 and vegas handles that better.

I just need to find a program to remux to mp4 as fast as obs does.

Interesting. I still wonder why it isn't doing a bit better on the benchmark for both render times and playback of the loop section. If you watch the CPU, GPU and temps with a tool like Intel Extreme Tuning Utility is it maintaining high clock speeds and reasonable temperatures all the way through the render?

Does ShutterEncoder work for you for the remuxing?

I tried shutter encoder. The remuxing takes almost as long as rendering a video.

My cpu and gpu temps are low. Vegas is using only the 2 logical processors that is clocked at 5.80ghz. The gpu usage is also low

I see. Odd that it's slower than similar systems. My CPU and GPU temps also stay quite low so there's no throttling.

Here's a screenshot of mine rendering with NVENC.

and with just the CPU

This is with hardware on. 01m:13.14s

Hardware off 01m:08.94s

I had 2 monitors on during my first test. I disabled 1 and updated to the latest game drivers for this test. I'm on windows 10.

GPU usage is really off. There should be 3D activity, it's like the NVIDIA GPU is disabled in preferences/video.

Not sure how to fix it- do a DDU uninstall of the drivers and install Studio driver 522.30 or the current one? Reset Vegas? Or at least run the C:\Program Files\VEGAS\VEGAS Pro 20.0 So4HardwareDetection.exe and refind the GPU?

I also run Vegas with 2 monitors plugged into my 2080.

I am on Windows 11 which may better utilize P vs E cores.

I tried shutter encoder. The remuxing takes almost as long as rendering a video.

@wedge Your computer isn't working properly, so your testing of remuxed mp4's isn't admissible evidence, shutter encoder (ffmpeg) should be similar to OBS for remuxing. It took 6 seconds to remux a 100minute 1440P MKV using shutter encoder, 8 seconds for OBS.

But if you get to the bottom of your problem, test again

Here is a ticket about the mkv remux problem and why it happens. https://trac.ffmpeg.org/ticket/7927

Here is a reddit thread with a solution video at the end (youtube video id = mgS-UOADIH4).

Remux in Shutter Encoder still results in a vfr video. Needed to use ffmpeg from cmd and set the timescale. The video above shows an easier way to do it without going to the command line.

I did a ddu uninstall and installed studio drivers from nvidia. There is still low usage on the gpu.

Rendering 4k 60fps with no hardware acceleration in vegas 18 does it at an average of 58-59fps(1 video and 1 audio track). Vegas 20 averages about 45 for the same project. With Legacy decoding on, Vegas 20 rendering speed is about 56fps

I did a ddu uninstall and installed studio drivers from nvidia. There is still low usage on the gpu.

Too bad, I hoped the drivers would have fixed it.
It would be worth getting to the bottom of this. Does the GPU perform normally in benchmarks? Intel Extreme Tuning, Timespy, Cinebench, etc.? Encode and decode seems to work but that's about it.

Here is a ticket about the mkv remux problem and why it happens. https://trac.ffmpeg.org/ticket/7927

Here is a reddit thread with a solution video at the end (youtube video id = mgS-UOADIH4).

Remux in Shutter Encoder still results in a vfr video. Needed to use ffmpeg from cmd and set the timescale. The video above shows an easier way to do it without going to the command line.

@wedge That's very interesting what you're finding out about FFMPEG muxing, and actually turns out Shutter encoder isn't using FFMPEG to remux, it's using TSMUX, this is it's 'console' showing the various software the GUI uses that I don't normally see.

Here's the same remuxing problem described a little differently.

This is a feature, not a bug. ffmpeg uses a time base of 1/90000 for MP4 files. 24000/1001 cannot be represented exactly as N/90000 where N is an integer. It works out to 7353.75/90000. Using either 7353/90000 or 7354/90000 would result in a slow drift from the true frame rate. So ffmpeg uses a variable frame rate alternating between 3753/90000 for 1 frame and 3754/90000 for 3 frames. So technically it's variable frame rate. But it's effectively a constant frame rate.

Such a "variable" framerate really shouldn't be a problem in Vegas. Is there another characteristic with the MKV conversion that's causing problems with the decoder?

@RogerS I think it's just a sensitivity to anything other than perfect CFR, and that's why mobile phone video and remuxed MKV to MP4 cause vegas problems but not most other editors.

I compared directly recording to mp4 in OBS with traditional record to MKV, remux to MP4.

Encoding the 2 didn't really show the problem, 95fps for Muxed VFR, and 97fos fps for CFR. On the timeline(Best/Full) I was blending the remuxed MP4(vfr) video - fade in/out. This showed the problem, GPU decoder overloads accompanied by frame drops. This is a 1440P AVC at 30fps GOP of 60 and only 1 B frame(which Vegas likes). Tried with non muxed CFR mp4, Gpu decoder doesn't overload, and there is no frame drop

This is a comparison, Vegas can lag at 30fps with a fade, while Resolve doesn't drop frames at 8x speed(240fps) At 16x when the decoder appears to be legitimately overloaded, it doesn't lag like Vegas can at 1x speed.

Also I"ll note, I don't have a problem editing this material, I've modified the OBS settings to suit Vegas, but obviously higher frame rates, more complex encoding etc causes worse problems, even when it's real CFR. I've mentioned before, if you have enough CPU don't use the GPU decoder, much of the lag goes away and GPU decoding crashes.

Hmm, wonder if the Intel and NVIDIA decoder have the same issues.Can you share that remuxed file for me to try out here? 1 b frame and 2s GOP really should work... but may not. Point taken on if you have enough CPU to just use that for such files.

@RogerS Could you try this one instead, it's the auto GOP setting that most people will be using when they complain about OBS lagging. The interesting thing is how often the GOP changes, I would think with many video games it will change like that too. Could that be what Vegas doesn't like, although longer GOP would seem to make more sense.

https://www.dropbox.com/s/r08z7cyunmnibl9/Capture6.mp4?dl=0

I chopped this one up a bit but didn't notice particular issue decoding it even at best/full. It was steadily at 59.940 with seldom drops even with crossfades.