"Frames missed due to rendering" increasing but I haven't started to do anything yet

[Rod Corkum]

Hi, I'm new to OBS. Just downloaded and installed yesterday.

BACKGROUND: I want to copy some old VHS tapes to digital files for a friend so using my Dazzle DVC100 that I haven't used for some years. The old Pinnacle Studio software is not giving good results so I found OBS. I couldn't get OBS to take audio input from the Dazzle so I found another post here that linked to a YouTube with a solution. I followed all the setup tweaks in that video and used their audio suggestion ... route the video through the Dazzle but the audio direct to the computer. I don't have an audio line input so used the front microphone input. It worked and solved the audio problem. Looks like I'm good to go now.

QUESTION: When I turned my computer on this morning and opened OBS to start copying tapes I noticed in the Stats window that some of the items there are showing activity as is the audio meter showing a very low level of audio. I haven't turned on the VCR yet and haven't started recording anything. I'm guessing this may not impact my recording (will know after I test it). See the arrows in the picture here. The "Frames missed due to rendering lag" keeps counting higher which sounds odd since I'm not recording. The "Average time to render frames" just changes a bit between .4 and .8, and "CPU usage" changes a little back and forth too. I'm assuming the other items including audio mixer activity may just be minor background signals or activity in the cabling or program but I don't understand what the "Frames missed" is counting. In the time it's taken to write this it has increased to 248 / 97400.

 

[R1CH]

OBS is always rendering the scene even if sources are not changing. If you've added a capture device, it will typically still output frames to the application (i.e. OBS) even if it isn't receiving any itself from the input side. OBS runs at 60 FPS by default which allows just over 16ms to render a frame - 60 FPS is more than you need for digitizing VHS so you could drop this to PAL / NTSC frame rates which would give OBS more time to render a frame and reduce the risk of frames being missed due to rendering lag.

 

[Rod Corkum]

OBS is always rendering the scene even if sources are not changing. If you've added a capture device, it will typically still output frames to the application (i.e. OBS) even if it isn't receiving any itself from the input side. OBS runs at 60 FPS by default which allows just over 16ms to render a frame - 60 FPS is more than you need for digitizing VHS so you could drop this to PAL / NTSC frame rates which would give OBS more time to render a frame and reduce the risk of frames being missed due to rendering lag.

Thanks. The video that I watched from another post on this forum (https://youtu.be/tk-n7IlrXI4?si=X5byOOjQr9sUyqZ1) had said to set it at
59.94 which is why I have that number (and the 1440x1080 resolution). Which of these FPS options would you recommend ... the 24 NTSC? The VHS tapes I'm copying from aren't the best quality anyway ... presumably copies of originals.

 

[Rod Corkum]

OBS is always rendering the scene even if sources are not changing. If you've added a capture device, it will typically still output frames to the application (i.e. OBS) even if it isn't receiving any itself from the input side. OBS runs at 60 FPS by default which allows just over 16ms to render a frame - 60 FPS is more than you need for digitizing VHS so you could drop this to PAL / NTSC frame rates which would give OBS more time to render a frame and reduce the risk of frames being missed due to rendering lag.

PS to my previous message ... I just tried a couple short tests at both that 59.94 and at the 24 NTSC and on playback I can't really notice any difference so I guess that one is OK.

One other comment I might add is regarding noise filtering. One of the tapes has a fair bit of background noise and I experimented with these noise suppression filters. Speex didn't seem to make any difference but while RNNoise significantly cut the background noise, it also resulted in the audio becoming very choppy and broken up. So I turned it off and left things alone. I have a minor bit of editing to do to these tapes in another program and I suppose I could take the soundtrack into Audacity (I've used that audio editor and it is reasonably good with noise reduction) and then bring the audio track back into my editor but seems like a lot of work for these old tapes so I'll probably leave the audio as is ... it is what it is!

 

[R1CH]

59.94 is usually for interlaced content, in OBS you can set deinterlacing on the source if the capture device doesn't do that already which brings it down to 29.97. The noise suppression filters are generally tuned to voices and will remove any non-voice audio so they might not help in your case.

 

[Rod Corkum]

59.94 is usually for interlaced content, in OBS you can set deinterlacing on the source if the capture device doesn't do that already which brings it down to 29.97. The noise suppression filters are generally tuned to voices and will remove any non-voice audio so they might not help in your case.

Thank you.