Audio Stutter After GFX Upgrade (750Ti)

[nxsfan]

My HTPC was working great with a GTX460. (Windows 8.1 64 bit). It was so stable that I hadn't upgraded the Nvidia drivers since late 2013.

I bought and installed a 750Ti and updated to the latest drivers (344.75) and since then I have many issues related to sound in WMC. These problems only occur when using HDMI passthrough on my receiver to my 2013 Samsung TV.

On many (all?) cable channels I suffer from choppy sound. It sounds as though I'm listening to very low bit-rate audio. This problem also exists for recorded TV. If I play the same recorded WTV files using Media Player or MPC-HC the problem disappears. I have double checked that the problem isn't caused by the 29/59 bug.

I have tried enabling "Volume Normalization" so that WMC doesn't bitstream DD. Not only does this not fix the problem, but the first time (every first time) I try and play a channel after enabling this, the computer hard crashes with some graphical artifacts. After spontaneously rebooting the channels play fine and exhibit the same audio issues.

If I turn on my receiver so it is decoding the audio, everything works great.

I tried rolling back to the 340.43 driver, but the problem persisted. I did a clean driver install (using nvidia's installer) and I also excluded the Miracast driver (I don't need it). No effect. I tried reinstalling the 2013 driver I used previously, but the installer quits as it doesn't recognise the 750Ti.

I'm really hoping someone here knows the answer because my wife was already unhappy with me buying a new graphics card! Stupidly I loaned the GTX460 before I noticed the problem so I can't easily swap it back in to see if the problems resolve themselves.

[nxsfan]

Well, I feel a bit daft for creating a thread now (I honestly spent some time trying to fix it before posting). Apparently I checked at a bad time when I ruled out the 29/59 bug. It's not that exactly, but the stuttering was caused by a similar problem, with the framerate alternating between 14.95 and 29.97.

I tried extracting and manually installing the audio driver from my 2013 driver (331.82) but then I had no audio device. Then I tried a clean install of the oldest Nvidia driver listed as compatible with my 750Ti (334.89) - and the problem disappeared!

It seems like my system was having some pretty major issues with recent Nvidia drivers. I had one recording that caused the computer to hard crash whenever we tried to play it - I wasn't sure what the problem was. This recording plays with absolutely no issues on the 334.89 drivers.

[newfiend]

I have a EVGA GTX 750Ti SC in my HTPC..
I am using the latest NVidia Driver 344.75 w/o issue.
In NVidia Control Panel select Adjust Desktop color settings.
On #2 set to use NVidia Settings
On #3 set Digital Color Format to YCbCr444 (for better color)
On Content Type reported to display to Full-Screen Videos (this should help with any screen blanking and possibly Audio issues)
Click Apply in the lower right corner and then confirm the changes when prompted.
I have had best results with all NVidia cards with these settings for HTPC use.
I also use HDMI out from HTPC > Receiver > TV.
Hope that helps.
newfiend

[crawfish]

On #3 set Digital Color Format to YCbCr444 (for better color)

That's going to cause the card to compress all output to 16-235. The only reason you would ever want to do that is if your display only supports 16-235, in which case, the desktop can never look right if the card is left at RGB. When you Use YCbCr444, for video to work right, it will have to first be expanded to 0-255, with the final compression resulting in a levels round trip for video (16-235 -> 0-255 -> 16-235) that can cause banding and of course discards BTB and WTW. It's normally better to leave it at the default RGB, which causes the card to output normal RGB 0-255, and then in your video player or renderer, you can choose the default Video Levels (16-235), which is passthrough, or expand to PC Levels (0-255) for consistency with the desktop.

For a normal display, if YCrCr444 gives you "better color", you have a calibration problem.

[nxsfan]

I have a EVGA GTX 750Ti SC in my HTPC..
I am using the latest NVidia Driver 344.75 w/o issue.
In NVidia Control Panel select Adjust Desktop color settings.
On #2 set to use NVidia Settings
On #3 set Digital Color Format to YCbCr444 (for better color)
On Content Type reported to display to Full-Screen Videos (this should help with any screen blanking and possibly Audio issues)
Click Apply in the lower right corner and then confirm the changes when prompted.
I have had best results with all NVidia cards with these settings for HTPC use.
I also use HDMI out from HTPC > Receiver > TV.
Hope that helps.
newfiend

Thanks for your response, it's very interesting as I also have the EVGA GTX 750Ti SC and experienced these problems. It seems significant (beyond user error) that I can change to an older driver and the problem goes away, so I'm bemused you don't see it. What is your setup like? Are you always streaming to a receiver? Or do you go directly to a TV?

I noticed when using HDMI passthrough, my computer is decoding to PCM and does not show DD support for my TV. This might be an artifact of HDMI passthrough, or the HDMI splitter I'm using. If your computer is streaming DD to your TV perhaps that's why you didn't see the problem? If you look at 411+Info does it look like mine?

I do change my content type, and I use the MadVR registry hack to change my system range to 0-255.

[newfiend]

On #3 set Digital Color Format to YCbCr444 (for better color)

That's going to cause the card to compress all output to 16-235. The only reason you would ever want to do that is if your display only supports 16-235, in which case, the desktop can never look right if the card is left at RGB. When you Use YCbCr444, for video to work right, it will have to first be expanded to 0-255, with the final compression resulting in a levels round trip for video (16-235 -> 0-255 -> 16-235) that can cause banding and of course discards BTB and WTW. It's normally better to leave it at the default RGB, which causes the card to output normal RGB 0-255, and then in your video player or renderer, you can choose the default Video Levels (16-235), which is passthrough, or expand to PC Levels (0-255) for consistency with the desktop.

For a normal display, if YCrCr444 gives you "better color", you have a calibration problem.

From Years back on the old TGB site I was told by many to set the digital color format to YCbCr444 when using HDMI (on a TV not Monitor display) and then to set dynamic range to 0-255.. barnabass (prior to getting the boot) suggested in another thread here that setting that to 0-255 would mess up the black levels. If I leave my screen at RGB the desktop looks fine but a bit (for lack of better terms) white washed a bit. Setting the Color format to YCbCr444 seems to give me better color on my display. It could be a calibration issue.. however since I don't use the TV for a lot of desktop activities and just TV and Games this seems to give me the best results.
What settings would you recommend?
newfiend~

[newfiend]

I have a EVGA GTX 750Ti SC in my HTPC..
I am using the latest NVidia Driver 344.75 w/o issue.
In NVidia Control Panel select Adjust Desktop color settings.
On #2 set to use NVidia Settings
On #3 set Digital Color Format to YCbCr444 (for better color)
On Content Type reported to display to Full-Screen Videos (this should help with any screen blanking and possibly Audio issues)
Click Apply in the lower right corner and then confirm the changes when prompted.
I have had best results with all NVidia cards with these settings for HTPC use.
I also use HDMI out from HTPC > Receiver > TV.
Hope that helps.
newfiend

Thanks for your response, it's very interesting as I also have the EVGA GTX 750Ti SC and experienced these problems. It seems significant (beyond user error) that I can change to an older driver and the problem goes away, so I'm bemused you don't see it. What is your setup like? Are you always streaming to a receiver? Or do you go directly to a TV?

I noticed when using HDMI passthrough, my computer is decoding to PCM and does not show DD support for my TV. This might be an artifact of HDMI passthrough, or the HDMI splitter I'm using. If your computer is streaming DD to your TV perhaps that's why you didn't see the problem? If you look at 411+Info does it look like mine?

I do change my content type, and I use the MadVR registry hack to change my system range to 0-255.

I actually had lots of issues with NVidia drivers (approx two builds back) that had a handles leak issue. it would get so bad in fact it would crash ehshell.exe. See this thread http://www.thegreenbutton.tv/forums/vie ... f=5&t=7768
It was caused by 29/59 content.. (Which HGTV is famous for BTW) I see that your TV picture is currently on that channel which exhibits that bug on a number of shows (including ones my wife loves to watch) talk about WAF in the toilet.. The latest two builds of the Nvidia Driver seem ok for me.
Setting the Content Type reported to display to full screen videos seems to fix the Screen Blanking and issues with 29/59 for me which may also cause your audio issue. ( I could be wrong but I would give it a try).
I use LAV Filters and the Win7DSFilterTweaker and set my codecs up from the suggestions here http://www.thehtpc.net/htpc-tips-and-tw ... subtitles/
as I use Media Browser 3 and have had very good success. I haven't messed around with MadVR.
I do use HDMI from PC to Sony AVR and HDMI from AVR to TV. I set up LAV to bitstream all audio to the AVR for decoding and get perfect 5.1 for DD,DTS,DTS-HD and True-HD.
You'll see in the Pictures that the 411 Info says SPDIF Bitstream but all Audio travels over HDMI Cables from PC to AVR for decoding.

newfiend~

[crawfish]

From Years back on the old TGB site I was told by many to set the digital color format to YCbCr444 when using HDMI (on a TV not Monitor display) and then to set dynamic range to 0-255.. barnabass (prior to getting the boot) suggested in another thread here that setting that to 0-255 would mess up the black levels. If I leave my screen at RGB the desktop looks fine but a bit (for lack of better terms) white washed a bit. Setting the Color format to YCbCr444 seems to give me better color on my display. It could be a calibration issue.. however since I don't use the TV for a lot of desktop activities and just TV and Games this seems to give me the best results.

When using YCbCr444, you are actually compromising the desktop (all non-video output including games) by causing the card to compress the RGB (0-255) color space the computer uses to the 16-235 range implicit in YCbCr formats when it puts the data on the wire. This results in 36 fewer possible shades, but it'll look "right" on displays calibrated for Video Levels, where black is 16, and white is 235. It's one way to get consistency between desktop and video so that a single collection of TV settings works for both, but it's normally better to achieve this by outputting RGB and calibrating for PC Levels, where black is 0, and white is 255, so that the desktop is passthrough, and video is only mildly to negligibly compromised.

The primary reason to consider using YCbCr444 is if your display doesn't process RGB properly, but I would suspect a settings problem is more likely if you haven't identified a problem and simply think this improves things. This page talks about the formats and how to identify conversion problems using their pattern disc:

http://www.spearsandmunsil.com/portfoli ... r-space-2/

A second reason to consider YCbCr444 would be the desire for consistent desktop/video when running everything through an AVR with a single HDMI output when one or more other video devices can't be set to PC Levels. Again, using YCbCr444 creates the levels round trip for video that I described earlier, and it's best avoided when possible. I would prefer to connect the PC directly to a separate TV input so I could use RGB in this scenario.

What settings would you recommend?

I'm afraid there's no answer that isn't tl;dr, and YMMV depending on the specific hardware and software. I have Fermi and Kepler cards and use WMC and XBMC for video. I don't use madVR, LAV, codec packs, etc and can't comment on them. That said, I would start by restoring the Nvidia Digital Color Format to its default "RGB", and in the Video section of the Nvidia Control Panel, restore it to its default, "With the video player settings." Just restore all the defaults except possibly the "Content type reported to the display", which may be needed to stop the screen blanking that occurs with some TVs for the 29/59 bug. Then you need to decide if you want to optimize for video or achieve desktop/video consistency, so that one TV calibration works for both.

1. If you care about desktop/video consistency, and as a gamer, you should care, configure your player software to output PC Levels and set your TV accordingly, e.g. "Nonstandard" for my Panasonic plasma's HDMI/DVI Dynamic Range setting. This is ideal for the desktop but a compromise for video, because when video is expanded from Video Levels (16-235 AKA "RGB Limited") to PC Levels (0-255 AKA "RGB Full"), you sacrifice BTB (pixels < RGB 16), WTW (pixels > 235), and possibly consistency with other video devices, which is a problem if you're running everything through an AVR with a single HDMI output, and those devices don't support PC Levels (e.g. my one y/o Sony S5100 only supports RGB Limited, another name for Video Levels; they dropped the RGB Full or PC Levels option that was present in my old S350). You need to use the NominalRange hack to get WMC to output PC Levels, while XBMC outputs PC Levels by default.

2. If you care only about video, you can configure your player software to output Video Levels, and your PC's output of video should then be consistent with the default output of other video devices. Again, set your TV to its corresponding setting, which my Panasonic plasma calls "Standard (16-235)". This preserves BTB, which is useful for setting Brightness on the TV, and WTW, which is allowed to contain overshoots and worth preserving to some extent depending on who you talk to. The downside is that desktop colors will be a little off due to black and white crush, but this does not interfere with using the desktop or WMC UI, and XBMC now has a "Limited Range" option that causes it to output both UI and video at Video Levels. You don't need to do anything for WMC, but you do need to enable the "Use limited color range (16-235)" option in XBMC.

Note that (2) can be considered passthrough for video, because video encoded as standard YCbCr 4:2:0 contains pixel values that map to RGB 1-254, and that range fits fine in the card's 0-255 output, which is what you get when you leave Digital Color Format at its default "RGB". For (2), video can be output without expanding from Video Levels to PC Levels, i.e. without altering pixel values as is done in (1), and perhaps surprisingly, as must be done when you use YCbCr444, so the compression back to 16-235 works out.

To assess output of your video players, use video pattern sets like AVS HD 709 (MP4 files are available for use with WMC and XBMC), in particular the clipping patterns for setting Brightness and Contrast on the TV, and for the desktop, use a paint program and images like those at lagom.nl, in particular the Black Level and White Saturation images. Use the gradients to assess banding. To go beyond this, you really need a meter and software (I use a profiled i1D3 and Calman Enthusiast), though there's a chance adjusting Color/Tint with a blue filter or mode and SMPTE color bars pattern will help. For many TVs, the warmest color temperature setting and Cinema mode will be closest OOTB to the standard calibration targets.

For more on levels and what you should and shouldn't see in the AVS HD 709 patterns, see this message:

http://www.avsforum.com/forum/139-displ ... st26449881

Note that in that message, I was assuming the card is set to RGB and outputting 0-255, not YCbCr444 or any other option that compresses the color range.

[newfiend]

Awesome Crawfish.. Thanks for all the information. I can see you have spent much time calibrating and researching all this. I have not, so this was very informative. I have an older TV (Sony) LCD and may replace it in the next year or so. It's starting to show it's age a bit and I would like something slimmer and with 3D capability. I think at that point I will start fresh and calibrate everything. I did set my TV back to defaults and left Full-Screen Videos selected to help bypass 29/59 and switched back to RGB and output to 0-255 In NVidia Control Panel. I'll see how that looks for a bit.
Thanks!
newfiend~

[crawfish]

Awesome Crawfish.. Thanks for all the information. I can see you have spent much time calibrating and researching all this. I have not, so this was very informative. I have an older TV (Sony) LCD and may replace it in the next year or so.

Hope it helps. It's a complicated mess, and while the levels terminology is confusing, it's essential to understand it. Individual components like TVs can have their own unique considerations, which can make things really difficult if you don't have a good grasp of what you should be seeing based on the configuration choices you've made.

It's starting to show it's age a bit and I would like something slimmer and with 3D capability. I think at that point I will start fresh and calibrate everything. I did set my TV back to defaults and left Full-Screen Videos selected to help bypass 29/59 and switched back to RGB and output to 0-255 In NVidia Control Panel. I'll see how that looks for a bit.
Thanks!
newfiend~

The really important thing here is to download the AVS HD 709 patterns and check your black and white levels.

Note that if you set the video dynamic range to 0-255 in Nvidia Control Panel, WMC should respect it, and you won't need to use the NominalRange hack. However, I noticed a strange and subtle problem about a year ago affecting both WMC and XBMC (with DXVA2 enabled) with either it or the 16-235 option selected, which I described here:

http://forum.kodi.tv/showthread.php?tid=180884

That was why I said, "in the Video section of the Nvidia Control Panel, restore it to its default, 'With the video player settings.'" The bug may have been fixed since then, but it should be unnecessary to use the option in the first place as the players can be configured to give you the output you want, WMC with NominalRange if you want PC Levels, and XBMC with the limited range option in Gotham and later if you want Video Levels.

Also, the Microsoft guy who posted the NominalRange instructions a long time ago started his message with, "Do NOT use the nvidia control panel settings to set dynamic range.Set it to application default (or whatever it's called). Using the nvidia setting exposes the flickering." He may have been leaving "Dynamic Contrast" enabled and mistook that for the Dynamic Range setting causing the 29/59 flicker, but even so, this does emphasize you don't need to use the Nvidia Control Panel to get the levels you want out of WMC. You can use NominalRange instead.

[crawfish]

One more thing... You may have heard of the Nvidia registry setting SetDefaultFullRGBRangeOnHDMI. Apparently, there are some card/display combinations that result in Nvidia cards outputting compressed RGB (16-235) over HDMI and DisplayPort, which appears as elevated or grayish blacks and an overall washed out image on a display expecting PC Levels. This is a YMMV thing, but if you are affected by it, there is a tool that allows you to apply the registry hack without having to edit the installer's .inf files, which was the old way to do it:

http://blog.metaclassofnil.com/?p=83

[STC]

Nicely written crawfish.

I actually use YCbCr output through my HTPC (ATI) as I get tighter calibration results especially through the gamma curve.- 10 point lines up without too much hassle whereas HTPC RGB full or limited is more of a problem. It's the least trouble having most sources set to YCbCr and the TV input calibrated to that colorspace. Our HTPC is only used for cable TV so colorspace conversion quality isn't an especially high requirement simply due to the low quality of the source.- MPEG compression with all its glorious blockiness.

For blu ray on a standalone player, YCbCr output is recommended as it is a consumer video format and this is the way HD is encoded.

[crawfish]

Nicely written crawfish.

Thanks.

I actually use YCbCr output through my HTPC (ATI) as I get tighter calibration results especially through the gamma curve.- 10 point lines up without too much hassle whereas HTPC RGB full or limited is more of a problem. It's the least trouble having most sources set to YCbCr and the TV input calibrated to that colorspace. Our HTPC is only used for cable TV so colorspace conversion quality isn't an especially high requirement simply due to the low quality of the source.- MPEG compression with all its glorious blockiness.

For blu ray on a standalone player, YCbCr output is recommended as it is a consumer video format and this is the way HD is encoded.

Whatever works. On their page I linked to, Spears and Munsil explain the best colorspace choice depends on a host of factors, and the YCbCr 4:2:0 standard video format is going to be converted to RGB somewhere. In particular, see the section, "The Conversion Chain" and the following discussion. Using their pattern, I could find no advantage to using my Sony S5100's YCbCr options, so I just go with RGB, which is the best choice for PC output. It measures the same as my HTPC, so I'm happy.

While I don't use his software, I've read that madshi, the author of madVR, recommends always outputting RGB Full (0-255) from video cards to avoid the levels round trip I described previously. I've always used it simply because it's the default, and there was no reason to change it. I've only recently come to understand it's possible to get graphics cards to compress all output to 16-235, which I got my Nvidia card to do by enabling YCbCr444. The latter results in weird things like finding a pixel value of 1 in Bar 17 of the AVS HD 709 Black Clipping pattern in a screenshot, yet it being just visible on a TV configured for Video Levels, where 16 is black. That's the result of video being expanded from 16-235 to 0-255 and then, after it's been written to memory, and just before the card puts it on the wire, compressed back to 16-235. It blew my mind when I was able to create that weird scenario I had always managed to avoid just by sticking to the defaults.

I truly hate the RGB Limited/Full and the corresponding Video/PC Levels terminology, because it's often used incorrectly or ambiguously. It can be used to refer to card output, in which case, Limited means compressing everything to 16-235, similar to enabling YCbCr444 for Nvidia cards, while Full means passthrough of 0-255, the latter being the native format for the PC. The terms can also be used to describe just video output, as Nvidia does in the video section of its Control Panel, in which "RGB Limited (16-235)" is passthrough for video, while "RGB Full (0-255)" means expanding Video Levels to PC Levels, throwing away BTB, WTW, and scaling 16-235 into 0-255. It's natural to think "Full" is better than "Limited", but this is not the case when talking about video.

[nxsfan]

Just an update, this problem was solved for me with the 347.09 driver.

Also I noticed something new (to me at least). I can now set the dynamic range for my HDMI display from Nvidia Control Panel without using a registry patcher:



Something else interesting that's not worth a dedicated thread. I used Steam streaming from my HTPC to my laptop without first closing WMC. I could hear TV on my laptop I was surprised that I could alt+tab on my HTPC to WMC (not full-screen) and watch and hear WMC on my laptop with very acceptable quality.