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Author Topic: Audio/Video Sync issues  (Read 17738 times)

nycmtber

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Audio/Video Sync issues
« on: January 03, 2013, 08:33:01 am »

Please help me narrow the focus to solve my problem.  The audio is usually slightly out of sync in both tv shows and movies.  some movies and shows seem to be worse than others.  rarely is it perfect.

i am using the high end red october setting.

I have video clock turned on.  I use WASAPI event connected via USB to a peachtree nova dac/preamp with a peachtree 220 power amp for a 2.0 system.  jriver is set to downmix to 2 channel audio.

i have jriver set to auto change the frequency for 24p, etc and have used all the recommended settings for the various formats.

I have windows 7 connected via HDMI to a samsung es6500 series led tv with an asrock vision HT computer (i5 processor) , intel hd4000, upgraded to 16gb memory.

all movies and tv shows are downloaded 720p or 1080p large files, generallly .mkv or similar.

where should I start???

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Matt

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Re: Audio/Video Sync issues
« Reply #1 on: January 03, 2013, 09:40:14 am »

Welcome.

It looks like you have things setup well.

It's possible you just need to configure Options > Video > Advanced > A/V Sync correction to compensate for any hardware delays.

This clip will help:
http://files.jriver.com/accessories/test_clips/audio_sync_test_25hz.vob

(ps. if anyone has good calibration clips like the one above for 24 fps and 60 fps that are a reasonable size, please share)
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Matt Ashland, JRiver Media Center

nycmtber

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Re: Audio/Video Sync issues
« Reply #2 on: January 03, 2013, 12:50:41 pm »

Thanks, I'll try it out tonight and let you know what I find.

just so it's out there, I also have media center master running in the background.  it's job is to watch a folder where movies and shows are downloaded and once completed rename and gather data then move to the proper folder on a different hard drive where jriver is watching.

is it possible this could be a windows OS issue?  I've not used windows in years (os x) and it's been quite a learning experience getting everything working. 

I originally started out with XBMC but it could not handle my music, and while spending years (ok, hours) of my life getting files properly coded for XBMC, I discovered jriver and started using it for audio only.  eventually i switched to everything.  version 18 seals the deal by handling my TV series how I want them...but i'm learning mostly that JRiver is not the limiting factor...it's me!

I've messed around with sharky codecs, and also tried manually installing various things to find video nirvana, and it's possible I screwed something up there.

anyways, i've done multiple XBMC installs and probably 2 or 3 jriver installs.  everything is golden now.  would it make sense to format and reinstall windows 7?
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mykillk

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Re: Audio/Video Sync issues
« Reply #3 on: January 04, 2013, 09:01:06 pm »

Is the audio coming early or coming late?

The delay is probably coming from one of two things: your TV's internal 24p processing or your USB DAC (or maybe both!). Should be easy to determine if it's just one or the other. Watch your videos at 60hz refresh rate. If you notice the same kind of sync issues that happen when you are using 24hz refresh rate, than it's not your TV adding the delay. If you DO notice that the sync is much better on 60hz, then it's the TV...

For some reason 24hz refresh rates seem to add 5 frames of delay on a lot of TVs. It did on mine. A bit of simple math will get you the appropriate length to delay the audio to compensate:

1 / 24 = 0.04167 seconds per frame = 41.67 ms per frame

5 x 41.67 = 208.35 ms

See if adding a 208ms delay to the audio helps.

If it's the USB DAC causing the delay, it's going to be a little more difficult. Instead of delaying the audio, you'll want to play the audio early. It'll take trial and error to find the right value, but you'll want to use a negative number for the audio delay, "negative delay" if you will :)
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bobkatz

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Re: Audio/Video Sync issues
« Reply #4 on: June 09, 2013, 08:46:03 pm »

I've been very silent on the forum for weeks to months because, well, everything is working perfectly. Then today with the help of Uli Bruegeman I've succeeded in getting Acourate Convolver to work in surround with Acourate ASIO and JRiver. Up to now it's only been stereo and I've implemented surround with a XO and parametric settings in JRiver options.

Now I've got tremendous latency in the audio, maybe more than 2.5 seconds. As you know, Acourate with its full FIR filtering and linear phase crossover and 65K filter length introduces tremendous audio latency. It's real hard for me to tell if the A/V sync correction is really working. I think it's bringing things closer (playing Star Trek Blu Ray) but the maximum negative (or positive) correction is -2500 ms. Matt, is there any way you can make that larger? Much larger perhaps. I'm just not sure until I zero in on it if I'm making a mistake, but I think it's getting closer and closer as I increase the negative value, but it looks like I need another second correction or even more. Can you please implement that in JRiver? God, the Acourate Convolution sounds good. If only I can get the sync. Nudge nudge  ;-).

Thanks in advance!!!!
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bobkatz

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Re: Audio/Video Sync issues
« Reply #5 on: June 09, 2013, 08:50:57 pm »

I'm about to try shorter hardware buffers. Maybe that will help the sync. Stand by.
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bobkatz

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Re: Audio/Video Sync issues
« Reply #6 on: June 09, 2013, 09:12:32 pm »

I'm about to try shorter hardware buffers. Maybe that will help the sync. Stand by.

OK, got it!!!!!   Using a shorter FFT partition in Acourate Convolver brought things well within JRiver's lipsync adjustment range. It gives me warnings that I'm exceeding the optimum realtime index, but so far there are no audible artifacts. Crossing fingers!!!

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bobkatz

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Re: Audio/Video Sync issues
« Reply #7 on: June 09, 2013, 11:07:40 pm »

OK, got it!!!!!   Using a shorter FFT partition in Acourate Convolver brought things well within JRiver's lipsync adjustment range. It gives me warnings that I'm exceeding the optimum realtime index, but so far there are no audible artifacts. Crossing fingers!!!



Well, it was a short-lived fix. I'm basically having VERY inconsistent video/audio sync issues. Have spent the last two hours trying different things but the sync is simply inconsistent. Sometimes the audio is 1 to 2 seconds late, sometimes the video. Changing the A/V sync in the options I have to make wild corrections. Restarting the app with the same blue ray produces different results. Have tried Red October standard and HQ. Seems to change the video delay a bit relative to the audio, but doesn't fix the inconsistency. Nothing I've tried fixes the inconsistency. At first I thought it was a difference from one blue ray title to another, but it was really the inconsistency even within two playbacks of the same title that gets to me.

I didn't have this with JRiver's own crossover and EQ. So I conclude it's something in the ASIO communication or the ASIO driver provided by Acourate that's not ensuring consistent A/V sync. Anyone else tried Acourate Convolver with JRiver having any success with A/V sync?
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6233638

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Re: Audio/Video Sync issues
« Reply #8 on: June 10, 2013, 11:20:31 am »

Unfortunately I don't have the opportunity to test Acourate Convolver, but it does sound like the plugin may be operating as fast as your system can process the audio rather than having a fixed buffer size, which is a nuisance when you are dealing with audio/video sync as it means the problem is essentially unfixable, unless this is changed.

I have had similar difficulties getting audio/video sync to be just right with Media Center though.
You would think that someone would have developed a device with a photosensor and a 3.5mm input to measure audio/video delays so that you can set up sync without any guesswork. (but again, it only works when the delay is fixed rather than variable)

Perhaps it would be best to get in touch with the Acourate Convolver team and see if they could make that an option? (if it isn't already - I am not familiar with it at all)
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mwillems

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Re: Audio/Video Sync issues
« Reply #9 on: June 10, 2013, 11:43:35 am »

Well, it was a short-lived fix. I'm basically having VERY inconsistent video/audio sync issues. Have spent the last two hours trying different things but the sync is simply inconsistent. Sometimes the audio is 1 to 2 seconds late, sometimes the video. Changing the A/V sync in the options I have to make wild corrections. Restarting the app with the same blue ray produces different results. Have tried Red October standard and HQ. Seems to change the video delay a bit relative to the audio, but doesn't fix the inconsistency. Nothing I've tried fixes the inconsistency. At first I thought it was a difference from one blue ray title to another, but it was really the inconsistency even within two playbacks of the same title that gets to me.

I didn't have this with JRiver's own crossover and EQ. So I conclude it's something in the ASIO communication or the ASIO driver provided by Acourate that's not ensuring consistent A/V sync. Anyone else tried Acourate Convolver with JRiver having any success with A/V sync?

I haven't used Acourate specifically, so forgive me if it won't export filters and this discussion is moot, but do you have the same problems when you try to use the same convolution filters with JRiver's built in convolution processor?  I ask because the JRiver DSP Studio convolution module attempts to adjust for delay and get things synced, and may work better for your specific application. 

The built-in convolution processor works for surround processing (at least for me), although writing the necessary config files can be a pain, and requires some trial and error.
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bobkatz

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Re: Audio/Video Sync issues
« Reply #10 on: June 12, 2013, 09:20:27 am »

Thanks for your help, guys. I also got help on the Acourate Forum. It turns out that there is no time-lock functionality between JRiver and Acourate Convolver. Restart and the audio video sync will likely be difference.

Acourate Convolver and Acourate ASIO works very well for audio only. So I converted my Acourate filters to wav format (64 bit float), created a config file compatible with sourceforge and JRiver, and am now using JRiver's convolver for video playback.

Works great! A/V sync is now perfect and consistent at 0 ms. And the sound is great too. Acourate's filters are the best-sounding out there, in my opinion.
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