I am having an issue playing a ripped DVD content using HDMI port: instead of the real sound all I'm hearing is a high-pitching chattering unbearable sound. At the same time if I reconnect my receiver to the optical SPDIF output instead of HDMI the sound is right and perfect. Another interesting detail is that the system sound (menu item click, etc.) and the movies in different formats like MP4, AVI, DivX all play with no problems via the HDMI. If while playing the ripped DVD movie I change the sound output from digital to analog the sound completely disappears so that does not help (and it should not as far as I understand, but tried it just in case). This problem exists on both XBMC 9.04 and 9.11 beta1 on Apple TV 3.01. Any help will be much appreciated.
2009-12-06, 21:52
There was another post regarding the same problem a year ago and it was not answered. Does anybody experience the same problem or it's just me?
2009-12-06, 22:13
konan Wrote:There was another post regarding the same problem a year ago and it was not answered. Does anybody experience the same problem or it's just me?
Can your receiver handle both ac3 and dts digital output over both HDMI and optical SPDIF ? Problem is AC3 or DTS or both?
2009-12-07, 04:06
The problem is with AC3 and I haven't tried DTS. There is another detail from my testing though, may be it'll help.
If I turn off the system sound (action clicks) in the system/Appearance menu then the chattering stops and the right sound starts coming via HDMI but without the center channel which is responsible for the voice when I play ripped DVD with DD 5.1 sound. If I have only a stereo sound track then I can hear it OK, but not the 5.1. For the 5.1 sound track even if I set "stereo to all channel" the center channel is still lost. When I turn the system sound back on the chattering noise returns back.
If I turn off the system sound (action clicks) in the system/Appearance menu then the chattering stops and the right sound starts coming via HDMI but without the center channel which is responsible for the voice when I play ripped DVD with DD 5.1 sound. If I have only a stereo sound track then I can hear it OK, but not the 5.1. For the 5.1 sound track even if I set "stereo to all channel" the center channel is still lost. When I turn the system sound back on the chattering noise returns back.
2009-12-07, 04:42
konan Wrote:The problem is with AC3 and I haven't tried DTS. There is another detail from my testing though, may be it'll help.
If I turn off the system sound (action clicks) in the system/Appearance menu then the chattering stops and the right sound starts coming via HDMI but without the center channel which is responsible for the voice when I play ripped DVD with DD 5.1 sound. If I have only a stereo sound track then I can hear it OK, but not the 5.1. For the 5.1 sound track even if I set "stereo to all channel" the center channel is still lost. When I turn the system sound back on the chattering noise returns back.
We call the chattering noise, the helicopters
It's AC3 being pumped out and the receiver not recognizing it as AC3. Not sure what to say, could be a HDMI version/handshake problem. Does AT3 output from frontrow ?
2009-12-08, 22:46
davilla Wrote:We call the chattering noise, the helicopters
How come that 2-channel AC3 plays OK and 5.1 AC3 does not via the same HDMI cable? How do I check the AC3 output from the frontrow (I run XBMC on Apple TV, not Mac)? How do I diagnose the cable? (do I need another cable, which version then, or another device to connect to, etc).
Thanks a lot for responding.
2009-12-08, 22:48
davilla Wrote:We call the chattering noise, the helicopters
So I take it that you don't think it's an XBMC bug. Could you then explain why turning off/on the system sound (System/Appearance) changes the behavior?
2009-12-09, 00:08
konan Wrote:So I take it that you don't think it's an XBMC bug. Could you then explain why turning off/on the system sound (System/Appearance) changes the behavior?
Send me your TV, receiver and computer, then I can tell if it's a bug in XBMC for Mac or not.
Two channel digital is simple, it's straight SPDIF, 5.1 AC3 digital requires a fake that require forcing the digital output to two channel and outputting multi-channel digital which not all receivers know how to decode correctly or some receivers are quite strict in the "specs".
In your setup (as far as I can tell), you output digital over HDMI to your TV, then route digital out from the TV to your receiver. You do know there's not a direct path, digital audio is interleaved with the video data over the HDMI data path, Your TV then de-interleaves the audio, reformats it and send it out it's digital port.
2009-12-10, 19:44
davilla Wrote:...
In your setup (as far as I can tell), you output digital over HDMI to your TV, then route digital out from the TV to your receiver. ...
Devilla, thanks for your answers and please don't be mad for me kept asking. I just want to understand where I am wrong and what perhaps I don't know.
So my setup is almost as you said except that I don't bother to send the digital output from my TV to a DD receiver (though technically I can). The problem starts with the TV: it can not play the AC3 5.1 DD sound from the ATV via HDMI; however it can play analog, AAC, or AC3 2.0 DD via HDMI. Is that a TV problem or HDM problem? I have tried multiple HDMI cables and multiple TVs with HDMI input and the behavior is absolutely the same: when the sound track is AC3 5.1 DD then I only hear the "helicopter" noise. Then I've tried an up-converting DVD player with HDMI output - it works OK with my cable and my TV. So my conclusion is that it's possible to output AC3 5.1 DD via HDMI but why ATV with XBMC cannot do that? Where am I wrong? If you know and can explain, please do, otherwise thanks for your time and sorry if I bothered you too much.
2009-12-10, 20:07
konan Wrote:Devilla, thanks for your answers and please don't be mad for me kept asking. I just want to understand where I am wrong and what perhaps I don't know.
So my setup is almost as you said except that I don't bother to send the digital output from my TV to a DD receiver (though technically I can). The problem starts with the TV: it can not play the AC3 5.1 DD sound from the ATV via HDMI; however it can play analog, AAC, or AC3 2.0 DD via HDMI. Is that a TV problem or HDM problem? I have tried multiple HDMI cables and multiple TVs with HDMI input and the behavior is absolutely the same: when the sound track is AC3 5.1 DD then I only hear the "helicopter" noise. Then I've tried an up-converting DVD player with HDMI output - it works OK with my cable and my TV. So my conclusion is that it's possible to output AC3 5.1 DD via HDMI but why ATV with XBMC cannot do that? Where am I wrong? If you know and can explain, please do, otherwise thanks for your time and sorry if I bothered you too much.
Now, I'm confused. Check your TV's manual regarding what digital audio it supports. Mine does not support 2 channel digital audio but not AC3 5.1 or DTS.
2009-12-10, 22:59
davilla Wrote:Now, I'm confused. Check your TV's manual regarding what digital audio it supports. Mine does not support 2 channel digital audio but not AC3 5.1 or DTS.
Yeah, I've got the same thing, with my Samsung TV. I was told by a 3rd tier support guy my TV was not licensed for dolby digital passthrough and I have to go optical from the ATV straight to the receiver.
2009-12-11, 18:43
tuckbodi Wrote:Yeah, I've got the same thing, with my Samsung TV. I was told by a 3rd tier support guy my TV was not licensed for dolby digital passthrough and I have to go optical from the ATV straight to the receiver.
Mine is straight out the back of the ATV to the receiver via HDMI, then to the TV via HDMI. Going from listening to music (2ch.) to a DVD rip (5.1ch.) will bring on the chattering.
2009-12-21, 18:53
I have the same problem with my analogue (Dolby Prologic) receiver. It happens sometimes after a while and when I pause or stop the music and continue it is gone. It seems to me that this has something to do with the decoder.
2010-01-25, 22:16
what i noticed is that the audio that is sent through hdmi to my receiver (ATV -> TV -> Receiver) is 5.1 PCM while at the same time the audio coming from the optical out on the apple tv it is sent encoded as DD 5.1. (i had connected both for testing at the same time and switched the input channels on my receiver)
I also have an dreambox where redirection of DD 5.1 content is working absolutely fine through hdmi, so this is not related to the TV used.
I also have an dreambox where redirection of DD 5.1 content is working absolutely fine through hdmi, so this is not related to the TV used.
Finally I have figured it out and have added the explanation to the Wiki here http://wiki.xbmc.org/?title=XBMC_for_Mac..._static.3F.
Basically the question has been answered many times by many people but one should collect all the answers together to understand. To recap:
when output DD encoded content via HDMI the output sound device must be able to decode DD otherwise you'll see the static noise sound. Most of TVs are not capable of DD decoding so the recommended solution is to use HDMI enabled AV receiver as the destination HDMI device. Otherwise use optical output or switch audio output to Analog.
Basically the question has been answered many times by many people but one should collect all the answers together to understand. To recap:
when output DD encoded content via HDMI the output sound device must be able to decode DD otherwise you'll see the static noise sound. Most of TVs are not capable of DD decoding so the recommended solution is to use HDMI enabled AV receiver as the destination HDMI device. Otherwise use optical output or switch audio output to Analog.
