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[madbrain]

I just upgraded from MC23 to MC24 primarily for the OTA subtitle feature.

When I watch live OTA ATSC channels and enable subtitles, there is massive delay and stuttering in the video. The sound is fine, though.
If watching sports channels, it's particularly comical. Turns basketball into some sort of odd dance. Hard to describe ! On programs without a lot of quick motion, the video almost looks fine.

If I disable the subtitles in MC, then the video plays fine at normal rate, without any pause.

Is anyone else seeing this problem ? Is it a known issue ? Is there a workaround ?

My hardware :
Asus Prime X470 Pro motherboard
AMD Ryzen 2700 CPU
16GB DDR4-2666
nVidia GT 1030 video card
Hauppauge quad-HD tuner card (4 ATSC tuners)
Hauppauge HVR-1850 tuner card (1 ATSC tuner)
Aquantia AQN-107 10Gbe NIC

Audio :
Marantz SR-7011 receiver

Display :
Optoma UHD65 4K projector, running at 4K60

Software :
Win10 x64 build 1809 (freshly installed, with all updates)
JRiver MC 24 x64 24.0.75
nVidia drivers 419.35
Hauppauge drivers 1.59.36248

[JimH]

You could try MC25.  Your license will work with it if you just bought.

[madbrain]

You could try MC25.  Your license will work with it if you just bought.

Just tried it. The stuttering problem remains unchanged. It seems like something slows down in the video rendering engine while displaying the captions.

If I turn off the captions, the video plays normally.

FYI, WinTV 8.5 that came with the cards displays the video with captions and no slowdown.

A good example to test this right now if you have an OTA tuner is to watch NCAA basketball. It was on my local CBS affiliate KPIX in the bay area.

[JimH]

What happens if you pause for 30 seconds?

[madbrain]

What happens if you pause for 30 seconds?

I'm not sure. I can't reproduce the problem at all at the moment, pause or not.
The issue might be specific to certain programs. During the live sports, the captions were being decoded one word at a time and scrolling on the screen.
But I am not seeing that on any other program now, even as I watch "live". I think the other programs showing on sunday night are pre-recorded and the captions don't behave the same way. They are just static and being quickly replaced one full line at a time, and there is no visible delay.

I will try to make a video the next time I see this happen.

[madbrain]

I will try to make a video the next time I see this happen.

Actually, I did reproduce it. And the answer to the question is, it doesn't matter if the video was paused for 30 seconds (or even many minutes).
There is a very brief stutter every time the captions update. It's as if every time the captions update, the video skips one frame.
In most programs, the captions don't upgrade very often, or there is not a lot of motion, so the skip isn't very noticeable.
But if there is, say, panning motion, as there is in many sports, or the captions are updated very frequently - for every word or even seemingly every character as they are being typed by manual caption operators - then it becomes very bad.

I made two videos that showed the stutter / no stutter with and without captions. They are not very good as I was shooting my projector, and handholding my cell phone. They do show the stuttering effect right at the moment the caption lines update, though.

First, without captions :
https://youtu.be/KN66l8Z3ZEo

Then, with captions :
https://youtu.be/MchZH0ix_bI

You can see (somewhat) that the scrolling of the genealogy tree is smooth in the first video, but not in the second video, where it stutters each time the caption lines are updated.

[madbrain]

Here is a much better video example of what I'm talking about.

With captions :
https://youtu.be/5UX8nLiaK4U

Without captions :
https://youtu.be/xZP5eUexQtI

[Yaobing]

Are you using Red October HQ?  It appears to be a problem only with HQ.  Try switching to using RO Std.

[madbrain]

Are you using Red October HQ?  It appears to be a problem only with HQ.  Try switching to using RO Std.

I was using the default settings when I first saw the problem on sunday. This was after fresh OS install and fresh MC install. I believe the default is Red october Std.

I have tried with HQ since, and I thought it might actually fix the issue, but I haven't confirmed that yet. I tried to do it last night, but unfortunately, to switch between Std and HQ, I had to hit the Stop button, and this causes the clips in the TV buffer to be discarded. Next time I'm home, I will try to explicitly record the clip. Not sure if I can do it retroactively - I would have to be able to go back to the point where I see the problem, hit record from there, and then stop, so I can just save that clip. Hopefully that will work. You seem to be saying HQ causes the issue, though, and Std fixes it, but I think it might be the other way around, at least on my system. Will update later.

[Yaobing]

If you set recording format to JTV, you can record from the beginning of the buffer.

In my testing I got stuttering when using HQ, but no problem using Std.

[madbrain]

If you set recording format to JTV, you can record from the beginning of the buffer.

In my testing I got stuttering when using HQ, but no problem using Std.

I have confirmed what I wrote earlier yesterday. I definitely see the problem with default (Std). The good news is that switching to HQ fixes the problem for me, so at least there is a workaround.

There is likely something hardware specific going on that explains our opposite results. Maybe some other combination of rendering settings, or drivers.

FYI, I have the checkbox set for "Hardware video decoding when possible". Not sure what the default is.

At least you have reproduced the problem on your system, even if under different settings than mine. If you have a test build for me to try, I'll test it same day. All my recent tests have been on MC25.

[Yaobing]

My video card is Intel built-in device.  It is not powerful enough for HQ.  I have to run HQ using the lowest profile setting MC to make video acceptable even without turning on closed captioning.  So in my case I think it is just an issue of my video card.  You having the opposite situation is a bit puzzling.

[madbrain]

My video card is Intel built-in device.  It is not powerful enough for HQ.  I have to run HQ using the lowest profile setting MC to make video acceptable even without turning on closed captioning.  So in my case I think it is just an issue of my video card.  You having the opposite situation is a bit puzzling.

Agree it is puzzling. But debugging this sort of issue is half of what makes software development fun, when you solve them, IMO

Let me know if you need any more info or logs about my system to help diagnose it.

[biasjordan]

Please let me know if you have found a fix.  I am experiencing same problem with MC 25 and subtitles, whether English or Spanish.

[Yaobing]

I have not been able to reproduce the issue, and have not found a solution.  If you have additional information, please provide it.

[biasjordan]

I have a 2-channel system.  I have had no problems until MC 25.  When I use subtitles for movies, I experience video stuttering at least once per minute:  left side of video always.  I have a Berkeley Reference I and a high-end media server.  Please advise. 

[JimH]

I have a 2-channel system.  I have had no problems until MC 25.  When I use subtitles for movies, I experience video stuttering at least once per minute:  left side of video always.  I have a Berkeley Reference I and a high-end media server.  Please advise. 

I'll move this to a new thread since this thread is for TV.

Try setting video to both Red October Standard and HQ.  I'm guessing RO Std will work and RO HQ won't.

Have you made any changes to madVR?

The video driver may also be a problem.

Take a look at "Weird Problems" in my signature.

[madbrain]

I have not been able to reproduce the issue, and have not found a solution.  If you have additional information, please provide it.

Sorry I didn't follow up earlier. I can still reproduce the problem. This is the case even though I switched from a low-end nVidia GT1030 to a slightly better GTX 1050Ti.

The problem can instantly be seen by turning on RO Standard, and then watching live TV from my Hauppauge tuner card with subtitles on.

Swiching to RO HQ solves the problem.

I'm guessing that the issue is specific to nVidia GPU. My machine is AMD Ryzen based, and then there is no integrated GPU for me to test with.