or Connect
AVS › AVS Forum › Audio › Audio theory, Setup and Chat › Audio sync issues, THX intro has no audio, and other woes of new setup
New Posts  All Forums:Forum Nav:

Audio sync issues, THX intro has no audio, and other woes of new setup

post #1 of 14
Thread Starter 
I got a new TV recently (LG 47LM7600) and have wasted countless hours trying to get it set up correctly with my PS3 (fat) and Denon AVR-1610 and 2.1 speakers. My initial setup had PS3 HDMI going into Denon (where audio was processed), and then Denon HDMI out going into TV.

Unfortunately, I noticed audio sync problems with certain Blurays (audio came too early). I tried upgrading all my HDMI cables to v1.4 and ensuring that audio sync was enabled on both the Denon and TV, but it didn't help. I could make the issue better by manually introducing a 100ms delay on the Denon, but I didn't like that approach because that delay wasn't needed for all content. I eventually narrowed the issue down to playing 24p content that was output at native framerate from PS3 to TV. In other words, f I disabled 24p output the sync issues went away. They also went away when I tried "game" mode on the TV. But I wasn't happy with either of those appproaches so my search continued...

Today I tried plugged the PS3 directly into the TV via HDMI and then connecting the TV's optical out to the Denon. I eventually got it working, and it seemed to fix the audio sync issue! smile.gif

But now for some reason the intro DTS-HD and THX sequences on the Terminator 2 Bluray are entirely silent. The audio in the movie itself is fine.

As an experiment, I tried enabling the TV speaker and the DTS-HD/THX intro sequence sounds came back. So the signal is definitely getting to the TV correctly and the TV is able to process it. And the problem seems to be that the receiver can't process that portion of the audio signal when it's fed via the optical input (It all worked fine when the PS3 hdmi out was hooked to the Denon!)

On the TVs audio out control you can choose between "Auto" and "PCM", and I've tried both. I've also tried having the Denon input format set to "Auto", "PCM" (the only other choice is DTS). On the Denon, the display shows no audio format text until after the THX sequence has ended, and then it displays "Dig" and "PCM".

Any help would be greatly appreciated!
Edited by cacophony777 - 9/13/12 at 11:07am
post #2 of 14
I fear you may be stuck with choosing whichever you decide is the least bad among the various options available to you:

0. replace your TV with one which can handle 24fps with no processing delays.

1. connect the player directly to the TV and connect the TV's digital audio output to the receiver. This handles the delay, but limits the number of audio channels.

2. connect the player to the TV and connect the player's digital audio output to the receiver. This is the worst option: it introduces the video processing delay and can only provide lossy multichannel audio to the receiver.

3. connect the player to the receiver and the receiver to the TV, allowing the video framerate to vary as appropriate. This does not handle the delay, but provides lossless multichannel audio.

4. connect the player to the receiver and the receiver to the TV, setting the player's video output to a fixed 1080p with 60 fps. This eliminates the need for audio display (no video processing is required in the TV), and also provides lossless multichannel audio. Note that you'll also need to disable all other video processing in the TV, too. E.g. edge enhancement, noise reduction etc. They all cause video processing delays.

Personally, I've choosen option 4 for my system: setting the video output to1080p60 in the player. I'm not sensitive to the judder caused by the 24-to-60 fps conversion, though. You might be. Your symptoms suggest that your TV is doing that frame rate conversion anyhow, so sending 24fps to the TV is a waste of effort.

Some background:
The audio output capability of TVs is limited. For example, most TVs output only two-channel PCM digital audio for all of the devices connected to them. They only provide multichannel audio for programs received by way of the TV's internal tuner. The player device is responsible for decoding the TV's EDID information and providing an appropriate signal to the TV. THX intros, as well as those sometimes provided by Dolby and DTS, are intentionally designed to demonstrate the advantages of high-quality multichannel audio. Apparently they're making use of surround-sound features that your TV simply can't provide.

The video is delayed when you watch 24fps inputs by way of the receiver because the TV has to process the video to make it compatible with its display. (Many LCD displays sold in the US can only refresh at 60 Hz.) When the player is connected directly to the TV, this conversion delay is known to the TV's electronics and is applied by the TV to the audio stream that it forwards. If the Auto delay setting isn't working for you when it's enabled in both the TV and the receiver, then either they're incompatible with one another or one of them is broken.

Since your TV apparently has to convert 24fps video to 60fps, though (otherwise there'd be no video delay), there's really no point in sending it 24fps to begin with.

I hope these comments help a little.
post #3 of 14
Quote:
Originally Posted by cacophony777 View Post

I got a new TV recently (LG 47LM7600) and have wasted countless hours trying to get it set up correctly with my PS3 (fat) and Denon AVR-1610 and 2.1 speakers. My initial setup had PS3 HDMI going into Denon (where audio was processed), and then Denon HDMI out going into TV.
Unfortunately, I noticed audio sync problems with certain Blurays (audio came too early). I tried upgrading all my HDMI cables to v1.4 and ensuring that audio sync was enabled on both the Denon and TV, but it didn't help. I could make the issue better by manually introducing a 100ms delay on the Denon, but I didn't like that approach because that delay wasn't needed for all content. I eventually narrowed the issue down to playing 24p content that was output at native framerate from PS3 to TV. In other words, f I disabled 24p output the sync issues went away. They also went away when I tried "game" mode on the TV. But I wasn't happy with either of those appproaches so my search continued...
Today I tried plugged the PS3 directly into the TV via HDMI and then connecting the TV's optical out to the Denon. I eventually got it working, and it seemed to fix the audio sync issue! smile.gif
But now for some reason the intro DTS-HD and THX sequences on the Terminator 2 Bluray are entirely silent. The audio in the movie itself is fine.
As an experiment, I tried enabling the TV speaker and the DTS-HD/THX intro sequence sounds came back. So the signal is definitely getting to the TV correctly and the TV is able to process it. And the problem seems to be that the receiver can't process that portion of the audio signal when it's fed via the optical input (It all worked fine when the PS3 hdmi out was hooked to the Denon!)
On the TVs audio out control you can choose between "Auto" and "PCM", and I've tried both. I've also tried having the Denon input format set to "Auto", "PCM" (the only other choice is DTS). On the Denon, the display shows no audio format text until after the THX sequence has ended, and then it displays "Dig" and "PCM".
Any help would be greatly appreciated!

Some of your problems may come from using the PS3 as a disc player. Its amazing how competent some of the ca. $100 Blu Ray players are. Might one of them help you?

BTW Seldon's post blew me away. In a perfect world you'd send him a check for all of that consulting that he did! ;-)
post #4 of 14
Thread Starter 
Quote:
Originally Posted by Selden Ball View Post

I fear you may be stuck with choosing whichever you decide is the least bad among the various options available to you:
0. replace your TV with one which can handle 24fps with no processing delays.
1. connect the player directly to the TV and connect the TV's digital audio output to the receiver. This handles the delay, but limits the number of audio channels.
2. connect the player to the TV and connect the player's digital audio output to the receiver. This is the worst option: it introduces the video processing delay and can only provide lossy multichannel audio to the receiver.
3. connect the player to the receiver and the receiver to the TV, allowing the video framerate to vary as appropriate. This does not handle the delay, but provides lossless multichannel audio.
4. connect the player to the receiver and the receiver to the TV, setting the player's video output to a fixed 1080p with 60 fps. This eliminates the need for audio display (no video processing is required in the TV), and also provides lossless multichannel audio. Note that you'll also need to disable all other video processing in the TV, too. E.g. edge enhancement, noise reduction etc. They all cause video processing delays.
Personally, I've choosen option 4 for my system: setting the video output to1080p60 in the player. I'm not sensitive to the judder caused by the 24-to-60 fps conversion, though. You might be. Your symptoms suggest that your TV is doing that frame rate conversion anyhow, so sending 24fps to the TV is a waste of effort.
Some background:
The audio output capability of TVs is limited. For example, most TVs output only two-channel PCM digital audio for all of the devices connected to them. They only provide multichannel audio for programs received by way of the TV's internal tuner. The player device is responsible for decoding the TV's EDID information and providing an appropriate signal to the TV. THX intros, as well as those sometimes provided by Dolby and DTS, are intentionally designed to demonstrate the advantages of high-quality multichannel audio. Apparently they're making use of surround-sound features that your TV simply can't provide.
The video is delayed when you watch 24fps inputs by way of the receiver because the TV has to process the video to make it compatible with its display. (Many LCD displays sold in the US can only refresh at 60 Hz.) When the player is connected directly to the TV, this conversion delay is known to the TV's electronics and is applied by the TV to the audio stream that it forwards. If the Auto delay setting isn't working for you when it's enabled in both the TV and the receiver, then either they're incompatible with one another or one of them is broken.
Since your TV apparently has to convert 24fps video to 60fps, though (otherwise there'd be no video delay), there's really no point in sending it 24fps to begin with.
I hope these comments help a little.

Wow, fantastic response! Thanks for taking the time to write it up as it helps tremendously.

The only thing that confused me are the comments about the TVs ability to handle 24p content natively. I had read that was a feature of this particular TV, and the native refresh rate is supposedly 120Hz (even though they advertise 240Hz), so I figured they could just play each frame 5 times. But I guess that counts as computationally expensive processing anyways (and isn't technically native)? There's a "real cinema" mode on the TV that can only be enabled for 24p content, which I figured was related. I like the idea of not having the 3:2 pulldown occur if possible.

I did eventually get approach (1) working for the THX sounds by messing with the PS3 hdmi audio out settings (forcing it to PCM). My speaker setup is only 2.1 so I don't really care about losing the multichannel audio by routing it through the TV. I couldn't hear a difference in quality, but it's hard to tell with these things.
post #5 of 14
Thread Starter 
Quote:
Originally Posted by arnyk View Post

Some of your problems may come from using the PS3 as a disc player. Its amazing how competent some of the ca. $100 Blu Ray players are. Might one of them help you?

So the PS3 is no longer considered a good Bluray player? At one point it was, but maybe that's changed. It's certainly fast to load content which I like.
post #6 of 14

The PS3 is a fine player, it is on par with any entry level player up until you get to the $500 mark IMO.  For my money the next upgrade of a player are the $250 mark players most notably the new Sony and for a little more money the OPPO93.

 

  • Which PS3 do you have?  Fat? Skinny?
  • Connect the PS3>AVR>TV in correct order normally and do a PS3 full reset.  With TV and AVR on and PS3 off, put finger on PS3 power button and hold until you hear second beep.  This will reset the PS3 handshake and output settings.  Go through audio and video setup as normal.
  • Turn off HDMI control on the PS3
  • Set HDMI audio output to linear PCM.
  • Why are you hung up on setting the PS3 to 24fps?  Don't force this setting.  Set this setting to Auto if you must have native 24frames going to the set, but many sets do poorly with this and is likely the source of your problem.
  • If the problem goes away with setting to 60frames leave it there, the conversion has to be made somewhere allow your system to do it where it results in the least hiccups.
post #7 of 14
Thread Starter 
Quote:
Originally Posted by NicksHitachi View Post

The PS3 is a fine player, it is on par with any entry level player up until you get to the $500 mark IMO.  For my money the next upgrade of a player are the $250 mark players most notably the new Sony and for a little more money the OPPO93.
  • Which PS3 do you have?  Fat? Skinny?
  • Connect the PS3>AVR>TV in correct order normally and do a PS3 full reset.  With TV and AVR on and PS3 off, put finger on PS3 power button and hold until you hear second beep.  This will reset the PS3 handshake and output settings.  Go through audio and video setup as normal.
  • Turn off HDMI control on the PS3
  • Set HDMI audio output to linear PCM.
  • Why are you hung up on setting the PS3 to 24fps?  Don't force this setting.  Set this setting to Auto if you must have native 24frames going to the set, but many sets do poorly with this and is likely the source of your problem.
  • If the problem goes away with setting to 60frames leave it there, the conversion has to be made somewhere allow your system to do it where it results in the least hiccups.

I have the old Fat PS3 (not the original one, but a later version that doesn't support PS2 games).
I currently have the 24p setting on the PS3 set to Automatic. Mainly, I'm trying to avoid an unnecessary 3:2 pulldown on 24p content. The TV supposedly has a 120Hz refresh rate, so it should be able to play 24p content more elegantly by just repeating frames, right? I wanted to avoid 3:2 pulldown because of the potential judder as a result.
post #8 of 14
Quote:
Originally Posted by cacophony777 View Post

Wow, fantastic response! Thanks for taking the time to write it up as it helps tremendously.
You're very welcome.
Quote:
The only thing that confused me are the comments about the TVs ability to handle 24p content natively. I had read that was a feature of this particular TV, and the native refresh rate is supposedly 120Hz (even though they advertise 240Hz), so I figured they could just play each frame 5 times. But I guess that counts as computationally expensive processing anyways (and isn't technically native)? There's a "real cinema" mode on the TV that can only be enabled for 24p content, which I figured was related. I like the idea of not having the 3:2 pulldown occur if possible.
Your experience suggests that it really doesn't support 24fps natively, even though it should be able to. However, after making my post, it occurred to me that the problem might not be the 24fps by itself, but perhaps it's being exacerbated by other video processing being enabled. Check to see if your TV has a Game mode, or some other way to disable all video processing. Edge enhancement (sharpening) and dynamic noise reduction are major contributors to any delay.
Quote:
I did eventually get approach (1) working for the THX sounds by messing with the PS3 hdmi audio out settings (forcing it to PCM). My speaker setup is only 2.1 so I don't really care about losing the multichannel audio by routing it through the TV. I couldn't hear a difference in quality, but it's hard to tell with these things.
There's not supposed to be any quality difference when PCM is selected. It uses the same decoding algorithm to convert Dolby and DTS lossless audio to LPCM in the player as would be used in the receiver (or TV). The TV should just pass the bits through unchanged. (Note my wishy-washy choice of "should". Too often people with appropriate test equipment have discovered that things which should not be touching the bits actually do.)

So long as you're running 2.1, then your choice seems quite reasonable to me.
post #9 of 14
Quote:
Originally Posted by cacophony777 View Post

So the PS3 is no longer considered a good Bluray player? At one point it was, but maybe that's changed. It's certainly fast to load content which I like.

I really don't know. This thread seems to make it out as being problematical, particularly as regards its support for various formats. Am I misunderstanding that? Someone help me out here.

Since the optical player in a modern AV system is connected to the AVR and the display via HDMI, the digital optical player is a strictly digital device that need not be costly in order to have excellent performance. This discussion of $500 optical players makes no sense because the only things that make optical players expensive is the circuity for format handling and conversion to analog, neither of which are used in a modern AV system.

In a modern AV system, the audio format handling and DACs are in the AVR. The video format handling and DACs (if they even exist) are in the display. (Those of us who use DLP video displays are watching pictures that are in the digital domain (intensity and color) until they hit our eyeballs.)
post #10 of 14
Quote:
Originally Posted by cacophony777 View Post

Quote:
Originally Posted by NicksHitachi View Post

The PS3 is a fine player, it is on par with any entry level player up until you get to the $500 mark IMO.  For my money the next upgrade of a player are the $250 mark players most notably the new Sony and for a little more money the OPPO93.
  • Which PS3 do you have?  Fat? Skinny?
  • Connect the PS3>AVR>TV in correct order normally and do a PS3 full reset.  With TV and AVR on and PS3 off, put finger on PS3 power button and hold until you hear second beep.  This will reset the PS3 handshake and output settings.  Go through audio and video setup as normal.
  • Turn off HDMI control on the PS3
  • Set HDMI audio output to linear PCM.
  • Why are you hung up on setting the PS3 to 24fps?  Don't force this setting.  Set this setting to Auto if you must have native 24frames going to the set, but many sets do poorly with this and is likely the source of your problem.
  • If the problem goes away with setting to 60frames leave it there, the conversion has to be made somewhere allow your system to do it where it results in the least hiccups.

I have the old Fat PS3 (not the original one, but a later version that doesn't support PS2 games).
I currently have the 24p setting on the PS3 set to Automatic. Mainly, I'm trying to avoid an unnecessary 3:2 pulldown on 24p content. The TV supposedly has a 120Hz refresh rate, so it should be able to play 24p content more elegantly by just repeating frames, right? I wanted to avoid 3:2 pulldown because of the potential judder as a result.

Follow what I told you above.

 

Make double sure the Audio is set to LPCM as the Fat cannot bitstream.

post #11 of 14
Thread Starter 
Quote:
Originally Posted by Selden Ball View Post

You're very welcome.
Your experience suggests that it really doesn't support 24fps natively, even though it should be able to. However, after making my post, it occurred to me that the problem might not be the 24fps by itself, but perhaps it's being exacerbated by other video processing being enabled. Check to see if your TV has a Game mode, or some other way to disable all video processing. Edge enhancement (sharpening) and dynamic noise reduction are major contributors to any delay.

I had noticed that game mode fixed the sync issue. Currently I have settings adjusted within "expert mode" because it gives the most flexibility. I have all video processing disabled though, with one exception: For some reason I felt compelled to leave "local dimming" set to low. I wonder if that could be introducing noticeable delays in the video processing...
post #12 of 14
Dimming has to be done digitally (unlike CRTs). Whether or not it introduces a delay would depend on how it's implemented. You'd have to try with and without it enabled to find out.
post #13 of 14
Thread Starter 
At this point the setup seems to meet my needs, so I think I'll leave well enough alone.

Thanks again for all the great info and advice smile.gif
This thread has been a tremendous help.
post #14 of 14
You're very welcome, of course.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Audio theory, Setup and Chat
AVS › AVS Forum › Audio › Audio theory, Setup and Chat › Audio sync issues, THX intro has no audio, and other woes of new setup