Let's set this straight - No one can do 24p consistently well - Page 28

What needs to happen on the PC is to extend the current video acceleration API's to handle the entire demuxing, decoding, and presentation process entirely on the video card (both audio and video). Right now you can feed a h.264 bitstream to the GPU and it will return decoded frames. But you're still stuck with Windows code handling the demuxing, a/v synchronization, and presentation. Here's where things typically start to go wrong:

1) Proper 100% accurate A/V synchronization is impossible because you have totally unrelated audio and video clocks. Audio or video frame drops are inevitable given enough time. This needs to be handled on the video card using the same base clock.
2) Proper presentation is also impossible because you're dealing with API's and hardware originally intended for games and applications - they can't natively display YUV interlaced content the way a dedicated STB using overlays can. You're also at the mercy of the Windows task scheduler as to whether your frames will even be presented on the correct vsync interval.

The closest thing to proper PC based playback were the old MyHD cards. Until someone else decides to release a similar product - you're going to keep fighting with the problems discussed in this thread. Of course none of this matters to the majority of the users in this thread. Only videphiles seem to notice or care about these issues.

how do you get the graphs on mpc-hc? is it on the evr renederer? i dont get it with madvr using ctrl-j.

with madvr you get the gui on the upper left when you do control J, its better IMHO because it tells you the time between frame drops/repeats and is done in a manner that most people can understand.

I have heard that if you use HDMI output at least in certain circumstances, they should use the video card clock, although I don't have hdmi audio receiver so haven't been able to test if there is a difference.

This will never happen. And even if it would, it would cripple the flexibility that actually makes the HTPC better (for us) then a out-of-the-box CE device.

Neither can any modern HD TV. The only thing that changes is where that change is made. If you use a CE device the TV is usually doing the deinterlacing and YUV->RGB conversion. If you use a HTPC, thats done inside the PC. One can argue that something like madVR can do a better job at the YUV->RGB then a TV can.
Edited by Nevcairiel - 8/14/12 at 12:39am

Is UAC Off still a requirement for intel playback at 23.973?

Thanks

No, it is not.
The information is just long out of date.

I appreciate everyone's help but I'm still confused what is happening. Regarding my earlier posting:
http://www.avsforum.com/t/1333324/lets-set-this-straight-no-one-can-do-24p-consistently-well/750#post_22294157

I don't get 23.973 fps or anywhere near it. Why is this? Is it because the movie is from a standard DVD instead of a Blu-ray disc?

I'm not sure that I agree with that. DirectShow has limitations, but I don't think it, Media Foundation, or alternate non-OOTB frameworks, are so intrinsically limited that it's not possible to build high quality video playback engines on top.

Regard my earlier posting:
http://www.avsforum.com/t/1333324/lets-set-this-straight-no-one-can-do-24p-consistently-well/720#post_22291924
Refresh rate: 59.xxx
Render device: Ati ... HD5800...

This scenario ONLY was possible thru an Ati performing a nearly clean 23.976 + 3:2 pulldown and a "modern" TV (i.e. Samsung D8000 Series) able to synchronize 59.xxx by the "Motion Plus" feature.


now your screenshot:
Refresh rate: 60.xxx
Render device: Intel HD Graphics...

So you need another TV to support the 59.xxx and maybe your Ati HD4200 does the rest -> MAY BE. Your Intel HD Graphics will not !!

-> nearly all values and graphs in EVR are influenced resp. determined by the hardware and there is nothing you can do about without changing the hardware !


or this earlier posting:
http://www.avsforum.com/t/1333324/lets-set-this-straight-no-one-can-do-24p-consistently-well/660#post_22288758

Ati performing a nearly clean 23.976 and a "modern" TV (i.e. Samsung D8000 Series) able to synchronize 23.976xx by the "Motion Plus" feature.
Edited by blaubart - 8/24/12 at 6:48am

My earlier image shows the fourth line:
Refresh rate: 60.00040 Hz SL:750 (59 Hz)
This is with the Intel graphics set to 59 Hz. The 60.xxxxx does fluctuate. Here's an example of 59.99113 fps.
Any idea what my HDTV is synching too?



If I change the Intel graphics setting to 60 Hz I get this.
Refresh rate: 60.xxxxx Hz SL:750 (60 Hz)
Almost the same except the (59 Hz) changes to (60 Hz). And the HDTV still synchs to something.

Just thinking about it, the HDTV synchs to DVDs and it also works with 30.000 fps .avi video from my digital camera. IOW it probably does not matter which setting I use for the Intel graphics, at least as far as the HDTV is concerned.

I understand I will not get perfect 23.976 fps without extra hardware or software.
But the very first message in this thread shows Assassin getting 23.973 fps. Is that because he was able to set his Intel graphics to 23 Hz, which if I understand correctly is really for 23.976?

I defer to you becuase you're more familiar with the actual guts, but it seems to me there are two fundamental problems:

1) Video is rendered to the "desktop" (using the term losely, because I know there's Fullscreen Exclusive mode rendering), and the desktop's refresh timing.
2) Audio and video clocks are distinct, different, and there is no way to sync them.

Regarding 1, this is basically the opposite of how CE/SOC players work, they render video, for lack of a better term "natively" and apply everything (menus/OSD) on top of that, vs the PC where everything (including the video, and the menus/OSD) is rendered to the "desktop" and is thus forced into the "desktop format", which is inherently a progressive format which means the output of native, untouched, interlaced video is impossible as it's first rendered to a progressive surface and then re-interlaced by a separate, disconnected process.

Regarding 2, I think this is really the problem at the root of this, in a CE player audio and video run of the same clock, so it really doesn't matter if the output is 23.976 or 24.004Hz because the audio and video are output are tied together. In the PC the audio runs on it's own clock that (to my knowledge) there is no way to adjust, which 'forces' us to manually adjust the refresh rate to be exactly "perfect" to match the locked audio clock, or to use something like reclock which "simulates" changing the audio clock to match the video.

Seems to me that to really match the "perfect" playback you get out of CE devices, you need to address these things, you need to create a new interface that directly ties decoded frames/fields to output frames/fields, to directly tie the output clock to the input frame rate, and then to automatically/directly tie the audio clock to the video/reference clock so it too can be output synchronized without the need for resampling or dropping/repeating bitstream frames. That and, as I saw a developer (I think) mention elsewhere, Windows isn't a real time OS, so that makes it harder to guarantee uninterrupted playback.

This is not correct, it is a problem. Audio has a fixed duration, independent of the clock or refresh rate. When audio was mastered for 23.976, and you output bitstreamed audio to your receiver, it'll decode this into audio which exactly fits a movie running at 23.976.
If the movie instead runs at 24.000Hz/FPS, it is slightly sped up, and over time audio and video will go out of sync, or you have to drop/repeat frames.

This is the big difference between video and audio. Audio has a fixed duration, there is exactly 48000/96000/... samples per second, and exactly x seconds of audio in a movie. Video on the other hand is not that much tied to its duration. The video can easily be shown at 23.976 or 24.000 without anyone ever knowing.
This is what ReClock fixes, re-sampling the decoded audio to adjust its duration to match the video clock.

Now going back why CE devices are better?
They have a dedicated clock which is designed to work on the crazy NTSC framerates like 23.9760 and 29.970, while a PC is designed to work on clocks like 60.000Hz and other even integer numbers (which also explains why 24.000 is easy for the PC, but 23.976 is usually harder)
Of course the PC effect is somewhat amplified because of the different clocks, which makes the job of syncing audio and video harder as well, but the "one clock" would not solve all the problems.

PS:
Regarding your first point, i already pointed out earlier that it may not necessarily be desirable to actually output "untouched" video. You have to deinterlace and convert to RGB at some point, so might as well be in the PC.
For the record, a CE device also cannot output "untouched" Blu-ray content for example. HDMI only supports 4:2:2 or 4:4:4, but a Blu-ray (or broadcasts for that matter) come in 4:2:0, so the CE device has to upsample that to 4:2:2 at least (and this conversion happens in the actual player, before it reaches any potential expensive video processor)
Edited by Nevcairiel - 8/15/12 at 5:29am

I'm not hearing any drift in audio or having dropped frames. I'm not completely sure but I think the "lip sync" function in my Denon AVR-2312ci keeps them together.

I am able to get 23.9xx (Lumagen processor rounds of to 23.98) from the Intel card for 2D bluray playback, unfortunately for Frame packed 3D the Intel card is only outputting 24P which creates all sorts of issues in 3D with Sync and Glasses. Any ideas on how to fix?

I'd rather have my deinterlacing and other video processing done in one of my Genum VXP video processors than an HTPC, or a Lumagen (if/when I get one of those).

PC maybe fine for most people, but getting top notch video out of a PC involves too many compromises IMO. To get the best out of a PC you have to use filters like madVR and LAV, which don't get me wrong, are great, but it means you can't use built in/integrated players like WMC's player, or TMTs player, etc, so you end up jumping back and forth between interfaces (both on screen and remote "API" interfaces), or you can stick with WMC or TMT, or whatever as the player and then you've got to accept the "average" video processing those support.

But you can get interlaced video out with the right field order and without having gone through a deinterlacing, you can get automatic refresh rate/resolution switching without jumping through hoops.

Is there a device besides the HD200/HD300 that does automatic resolution switching?

Besides FSE, a render can write directly out w/o needing to render/composite with the desktop. IIRC, the TMT renderer works in this way.

As long as the latency is good enough, I'm not sure that a real time OS is required.

Maybe for many on this thread you are right. But I strongly disagree. The last place I want the video processing done in in the PC. Many of us have high end VP's that are designed and dedicated to jsut that task and do a wonderful job of it, given the opportunity. As for HDMI, nothing will make me happer than to bypass it with HD-SDI. But alas, I don't see that happening on a PC, either. I wasn't aware the HDMI spec disallowed 4:2:0.

Lip-sync will only allow you to set a finite delay in teh audio, typically to make up for a fixed delay in video due to processing. It won't fix drift where they get worse over time. Only if they are out of sync and by a constant amount from start to end.

It is likely (I'd bet on it) you are not getting 23.976. Maybe 23.979, etc, but not a stable 6. So you'll get periodic frame issues. I see the saw the same frame rate on my Lumagen with rounding but I was running a confuguration known to be off. But as Assasin will point out, not all see them, and if your's is very close they happen far enough apart to make it less of an issue or a non-issue.

I know my Pioneer Blu-ray player will, these are the only devices in my possession I have experience with.

There's several ways to do automatic frame rate switching in WMC.

In WMC? Without jumping into external players? Including for TV?

The whole discussion is about replacing expensive consumer electronics equipment with your HTPC, so your use-case really falls outside of the discussion here.
If you want to combine your existing video processors with a HTPC, it may not be easy, but most people do not have such devices and just want the best they can get out of their HTPC which is simply connected either directly to a TV or a A/V Receiver in between. A HTPC is not only a player, its a player and processor in one, and thats how it works best. If you don't like that, its simply not for you.

The whole point is to use a HTPC, and only the HTPC. Its supposed to replace the video processor.
If you have such a video processor device, you might as well stick to a generic CE Blu-ray player or STB, because decoding is easy, and every device can do it.
Sorry to disappoint, but HD-SDI also does not allow 4:2:0.
Edited by Nevcairiel - 8/16/12 at 12:15am

Funny, I thought an HTPC could be whatever one wanted it to be, and the discussion was about achieving whatever one's goals with an HTPC are.

I'm curious who decided that's the only point of an HTPC? Now granted I've been around here long enough to remember when the primary purpose of most HTPCs was to replace high end line doublers, but "high end" video processors have not only gotten a lot better since then, they've become a lot more affordable (see the DVDo Edge).

But there's other stuff that CE devices don't do as well (as many here take so much joy in pointing out every time the issue comes up). Incidentally that is why the SageTV extenders are/were so great for me and why I'm excited about the Echo, they hold the promise of providing the excellent playback of a CE device with the media management capabilities of an HTPC.

It can be whatever you want it to be, within its limitations (which every device has).
Not being able to properly output interlaced material is one of its limitations, but one limitation that is not important for the majority of people (because todays GPUs actually do a OK job at deinterlacing), and will hopefully be even less of a problem in the future as interlacing slowly dies out.

Interesting, what model is it?

That is different from resolution switching (frame size). I'm quite familiar with the several of the methods for doing frame rate (and resolution for that matter) switching in WMC, having written at least two different solutions for doing that

The DTB Addin includes this feature. I can't remember if it works for Live TV, but it does for recorded TV and anything else where I can get the media properties.

There is a drawback to doing this in WMC (or any .NET GUI app) since the framework leaks memory with each display change there is a limit to how many you can do before the process needs to be recycled.