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Author Topic: Audio slightly out of sync (audio is slightly behind video)  (Read 12305 times)

zenpmd

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Audio slightly out of sync (audio is slightly behind video)
« on: March 27, 2016, 04:09:04 pm »

I am uisng windows and madvr. Can anyone recommend some trouble shooting steps? Thanks
I am playing ripped files
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Trumpetguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #1 on: March 27, 2016, 04:46:32 pm »

If it is a constant time difference, you can set a positive sync correction value in milliseconds here:
Tools>Options>Video>Advanced>A/V sync...etc

As an example, I use convolution DSP, which adds a delay to the audio track. By trial and error, I found that +95ms is a good value for all ripped movies - in my setup. You would need to test your way to the correct value for yours. For a few years, I used a 65ms (I think it was) delay, but sometime last year I had to change this to 95, apparently because of a code change. Just to let you know that this sometimes do occur.

Also, this setting is zone specific, so you would want to make sure you add the delay to the right zone.
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zenpmd

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #2 on: March 28, 2016, 03:42:17 am »

Thanks.

What is the cause of it? You seem to be implying that the time difference is always a constant?
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ferday

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #3 on: March 28, 2016, 04:04:48 am »

Because audio and video are processed differently, and each device in the chain will contribute, there is often lag.  It really noticeable in gaming (input lag)

Usually the video is behind the audio (but not always).  It's often fairly constant because your chain will lag them consistently, but some rips will encode with lag and then it might be different.  I find a fairly constant lag which differs depending on which setup I'm using
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flac.rules

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #4 on: March 28, 2016, 06:51:00 am »

Would it be an idea to implement a sync-tool in MC? Like a video with ticks and visual marks to sync up audio and video? I know you can download such videos, but an inbuilt tool would be a smoother solution.
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mojave

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #5 on: March 28, 2016, 09:47:03 am »

Would it be an idea to implement a sync-tool in MC? Like a video with ticks and visual marks to sync up audio and video? I know you can download such videos, but an inbuilt tool would be a smoother solution.
A video would be much larger than the size of the current JRiver .exe download. For example, the files I use are 291 MB total for 60 seconds of 4 different frame rates.
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Trumpetguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #6 on: March 28, 2016, 01:26:38 pm »

A video would be much larger than the size of the current JRiver .exe download. For example, the files I use are 291 MB total for 60 seconds of 4 different frame rates.

Would those files be legally available to others than yourself?
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Trumpetguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #7 on: March 28, 2016, 01:30:17 pm »

Thanks.

What is the cause of it? You seem to be implying that the time difference is always a constant?

I found that rips would always be out of sync with a constant time delay. With my previous computer, I struggled a lot because delays varied - both with which movie I was watching and it also varied throughout each movie. This was simply because my computer was not powerful enough. Some movies would be more cpu demanding than others, and caused the difference from one movie to the other. Some movies would accumulated delay while playing.

New computer = constant delay.
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mojave

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #8 on: March 28, 2016, 01:53:32 pm »

Would those files be legally available to others than yourself?
Yes. They are the test files for use with the Sync-One2, but will still work as stand alone files. Don't use the ones with a variable rate. JRiver can play any of the file formats.

http://www.sync-one2.co.uk/support/test-files/
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Trumpetguy

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Re: Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #9 on: March 28, 2016, 02:57:04 pm »

Yes. They are the test files for use with the Sync-One2, but will still work as stand alone files. Don't use the ones with a variable rate. JRiver can play any of the file formats.

http://www.sync-one2.co.uk/support/test-files/
Great, thanks!
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flac.rules

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #10 on: March 30, 2016, 11:08:53 am »

A video would be much larger than the size of the current JRiver .exe download. For example, the files I use are 291 MB total for 60 seconds of 4 different frame rates.

Hmm, yeah, that could be a problem (however 291 MB for 60 seconds of repeat simple content is pretty inefficient coding), maybe a downloadable component then, as the codecs?
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zenpmd

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #11 on: April 04, 2016, 01:54:44 pm »

Ok I have played around and I cannot get this to work, at all, using that method. Yet if I load the same film files into VLC it plays straight away. What can I try?

Thanks
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craigmcg

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #12 on: April 04, 2016, 04:54:28 pm »

Forgive me if I'm asking a really dumb question but have you already enabled VideoClock under Tools-Options-Video?
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zenpmd

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #13 on: April 05, 2016, 12:38:41 am »

Forgive me if I'm asking a really dumb question but have you already enabled VideoClock under Tools-Options-Video?

Yeah thats always checked :)
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Trumpetguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #14 on: April 05, 2016, 06:49:14 am »

I thought VideoClock would do the A/V sync automatically*. That would mean that the constant A/V sync option should have no function, right? If you use VideoClock, and still do not get good sync, doesn't that suggest your hardware is too weak?

Did you play with the different scaling algorithms in madvr, first trying the least cpu intensive alternatives?

* Side note: VideoClock resamples the audio to fit the video stream perfectly I think, which is why I do not use VideoClock since that has proven to garble my audio when using convolution DSP.
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zenpmd

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #15 on: April 05, 2016, 07:20:57 am »

I should point out I have this problem even using red book standard too, so I cannot see it's because the hardware doesn't have enough juice?

I am using the Asus p8h67-I deluxe wig it's onboard gfx and an i3 processor
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Trumpetguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #16 on: April 05, 2016, 07:35:26 am »

I should point out I have this problem even using red book standard too, so I cannot see it's because the hardware doesn't have enough juice?

I am using the Asus p8h67-I deluxe wig it's onboard gfx and an i3 processor

Red book standard? Redbook is audio CDs, so I don't know what that has to do with video playback? Or do you mean Red October Standard?
My i7 HTPC box with dedicated 960 nvidia card manages well, while my i5 laptop with intel integrated graphics does not handle ROHQ/madvr and needs to run with RO standard. I would not be surprised if your i3 with onboard gfx is too weak, at least for ROHQ. I wouldn't know with RO standard.
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zenpmd

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #17 on: April 05, 2016, 01:32:56 pm »

Red book standard? Redbook is audio CDs, so I don't know what that has to do with video playback? Or do you mean Red October Standard?
My i7 HTPC box with dedicated 960 nvidia card manages well, while my i5 laptop with intel integrated graphics does not handle ROHQ/madvr and needs to run with RO standard. I would not be surprised if your i3 with onboard gfx is too weak, at least for ROHQ. I wouldn't know with RO standard.

Yes, I am now trying RO standard and it has the same symptoms
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Trumpetguy

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Re: Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #18 on: April 05, 2016, 02:03:35 pm »

Yes, I am now trying RO standard and it has the same symptoms
I'm out of suggestions. Maybe someone else know if your computer should be up to the task? You could run an MC benchmark and post the result here. Useful for others to assess your pc in a more quantitative way.
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jincuteguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #19 on: April 05, 2016, 10:50:13 pm »

So I just got JRiver Media Center to work  with Games  as a WDM driver.  The only issue I have at the moment is the "delay" in audio.  Everytime I cast something in game, there's like a 1sec delay of Audio?
Is this JRiver always this slow?
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RD James

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #20 on: April 06, 2016, 07:59:43 am »

VideoClock prevents audio drift so that it won't gradually go out of sync by the time you get to the end of a long video. (e.g. 2 hour movie)
If there is a processing delay between your audio or video, it won't do anything to correct for that.
You need to set up an A/V Sync Correction in the JRiver video options.
 
I recommend shifting it by plus or minus 33ms until you get the correction in the right ballpark.
Usually if there is a sync problem, the issue is that video is appearing behind audio, but that's not always the case. It really depends on your audio/video hardware.
 
So I just got JRiver Media Center to work  with Games  as a WDM driver.  The only issue I have at the moment is the "delay" in audio.  Everytime I cast something in game, there's like a 1sec delay of Audio?
Is this JRiver always this slow?
That depends on your audio hardware.
Using the NVIDIA HDMI device on my system, I can set the buffers small enough that audio is in sync with browser-based video playback.
I haven't tried it with games though.
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Trumpetguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #21 on: April 06, 2016, 08:25:52 am »

So I just got JRiver Media Center to work  with Games  as a WDM driver.  The only issue I have at the moment is the "delay" in audio.  Everytime I cast something in game, there's like a 1sec delay of Audio?
Is this JRiver always this slow?

This issue is not related to the topic of this thread. Audio delay will depend on buffer sizes in your audio chain.
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zenpmd

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #22 on: April 06, 2016, 09:10:25 am »

With enough power can I assume there will be no sync issues?
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RD James

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #23 on: April 06, 2016, 09:29:28 am »

With enough power can I assume there will be no sync issues?
Audio sync is not a "power" issue.
Something in your playback chain is causing the audio or video to be delayed.
 
Televisions often have 100ms or more latency to process video.
Your DAC might have 30ms of latency.
So you would need a 70ms correction to bring the two into sync.
 
This is the nature of media playback on a PC where audio and video are separate devices.
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Trumpetguy

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #24 on: April 07, 2016, 02:28:12 am »

Audio sync is not a "power" issue.
Something in your playback chain is causing the audio or video to be delayed.


My experience is otherwise: if you put a lot of cpu load on the audio DSP, it can heavily compromise A/V sync.
But I agree that one should look closely for other sources of delay before buying new hardware!
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RD James

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #25 on: April 07, 2016, 02:50:37 am »

My experience is otherwise: if you put a lot of cpu load on the audio DSP, it can heavily compromise A/V sync.
But I agree that one should look closely for other sources of delay before buying new hardware!
Adding DSP can add latency, but the solution for that is not a faster system, it's setting up an offset to cancel it out.
If it adds a second of latency, you adjust the sync by 1000ms in the opposite direction.
Many VST plug-ins can do that automatically - or should - though it doesn't seem to work with everything in JRiver.
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zenpmd

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Re: Audio slightly out of sync (audio is slightly behind video)
« Reply #26 on: April 07, 2016, 03:05:20 am »

Audio sync is not a "power" issue.
Something in your playback chain is causing the audio or video to be delayed.
 
Televisions often have 100ms or more latency to process video.
Your DAC might have 30ms of latency.
So you would need a 70ms correction to bring the two into sync.
 
This is the nature of media playback on a PC where audio and video are separate devices.

Why do i not have this problem on box though ?
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