Discoverd a bug maybe?

[Ingram]

See my problems here with 720P MKV's and getting the red line to stay straight - http://forum.slysoft.com/showthread.php?t=40589

Well I have been fiddling and I've found out how to fix it, and recreate it!

The problem it seems, is when I use BEST SINC Interpolation + Time Stretching + Speeding Up.

Taking a 720P MKV which contains 640kbps AC3 track running @ 23.976FPS, speeding up to 25.000FPS and applying Time Stretching (don't even bother trying to tell me not to do it, I will not listen! :rock: ).

If I use the same configuration except use FAST SINC the red line is absolutely perfectly straight as a pencil!

The same can be said for GOOD SINC, however it's not as stable, but at least stays more consistently straight.

So it's specifically just BEST sync with the use of Time Stretching which results in a continual, perfectly timed blip in the red line graph, which causes the video to play unstable.

Best Sinc with Time Stretching off = Perfectly straight line!

I've added 3 log files, with each of the 3 Sinc qualities.

I checked my CPU Usage, and it's around 30% on BEST, so it surely isn't my CPU causing this.

Hopefully someone here can work out what's going on!

EDIT: In the meantime, I'm absolutely loving this 720P file running in DXVA and going from 15.7-15.9 MS sync offset. The red line has been perfectly straight for 15 minutes now.

And to be honest, using PAL Speedup with Fast Sinc probably hides any quality loss from dropping down from Best Sinc.

 

[James]

So it's specifically just BEST sync with the use of Time Stretching which results in a continual, perfectly timed blip in the red line graph, which causes the video to play unstable.

Very simple: Don't use it. Timestretching will destroy the sound anyway, it makes no sense to use anything else but "fast sinc". And without timestretching there is also no need to use "best sinc", "good" is probably as good as it gets. Or do you hear any difference between "good" and "best"? I seriously doubt it. I certainly don't. I dare to say nobody will. Certainly not with movie soundtracks.
Unless someone can hear differences between bit-exact and bit-exact like leeperry claims. But then, you wouldn't use time stretching.

 

[James]

I checked my CPU Usage, and it's around 30% on BEST, so it surely isn't my CPU causing this.

Hopefully someone here can work out what's going on!

It is the CPU & memory load. You probably won't see the spikes with a CPU monitor which displays CPU usage over time intervals. If your CPU is eaten up 100% for 1/25th of a second, you'll have stutter.

 

[James]

... and you're using the AC3 encoder. You're really pushing it.

 

[Ingram]

Yes but I'm using DXVA, so my CPU is sitting around doing nothing but handling the audio.

Here's a small niggle in your CPU theory though, I was watching Blu-Ray discs in PDVD8/10 without the stutter with Reclock and the same settings. You'd think that would take more oomph than a 720P MKV?

Oh well, I'm not that fussed, I'm just glad I found what was causing my issues.

At least I've documented that using the combination I've been trying to use will result in unstable playback for what I was trying to play.

To think up until this week I was ignorantly using EVR-CP without Reclock handling V-Sync and thinking everything was fine and dandy!

On an unrelated note, be damned what time stretching does to the audio quality, the first thing I notice when it's off is that everyone has been breathing in helium! Long before I'd stop to try and hear any audio quality improvements

When I get a new TV I can stop using Time Stretching...

 

[namaiki]

Here's a small niggle in your CPU theory though, I was watching Blu-Ray discs in PDVD8/10 without the stutter with Reclock and the same settings. You'd think that would take more oomph than a 720P MKV?

Is that still while using DXVA?

 

[leeperry]

like leeperry claims.

not sure what you're getting at but libsamplerate and libresample sound quite different, even in their highest quality mode.

 

[el Filou]

James was probably refering to the "different bit-exact players all sound different even though all are bit-exact" thing.

 

[leeperry]

James was probably refering to the "different bit-exact players all sound different even though all are bit-exact" thing.

well the OP was talking about SQ difference depending on the resampler quality...I was just saying that all the resamplers sound different, I personally much prefer libsamplerate over libresample...damn shame its coder is being so picky about GPL.

Well, the difference between bitperfect players are not just MY imagination...you can read zillion ppl saying the same thing: http://www.audioasylum.com/forums/pcaudio/messages/2/21586.html

even 11yo kids can DBT "bit-perfect" players

and some ppl tried to come up w/ technical explanations...software jitter comes to mind, and that'd explain why Reclock more less kills the competition in the realtime audio rendering department:
http://www.cicsmemoryplayer.com/index.php?n=CPlay.SoftwareInducedJitter

http://www.phasure.com/index.php?topic=692.0;all

 

[Ingram]

Is that still while using DXVA?

Of course, DXVA for the MKV and the Blu-Ray. My CPU doesn't have the omph to do 1080p, but it can do 720P fine.

Also, until now I was using EVR-CP and MKV's played fine far as I could see, before I started examining graphs and getting even more of a nerd

 

[namaiki]

Also, until now I was using EVR-CP and MKV's played fine far as I could see, before I started examining graphs and getting even more of a nerd

As I said in the other thread, AFAIK EVR-CP's sync graphs only apply when EVR-CP's Vsync is enabled.

Not to say that Reclock's Vsync correction isn't doing any good, just you're looking in the wrong place.

 

[Ingram]

When I was using EVR-CP I wasn't even thinking about or fiddling with V-Sync stuff, so it was all enabled/default whatever MPC-HC installs with.

Stuff played fine far as I could see, including 720P MKV. But there was probably moments of jitter that I wasn't noticing I guess.

Once I read on here about it I started fiddling, this is when I came across the problem with MKV's not running smoothly until I rolled back to Fast/Good SINC or left it on BEST and disabled Time Stretching.