[mythtv] Audio distortion issue on Nvidia Shield

Michael mythtv at blandford.net
Mon Sep 24 02:41:46 UTC 2018


On 9/19/18 11:45 AM, Peter Bennett wrote:
> I tried the latest build on my surround system and Dolby Digital works 
> fine. I am running version 7.0.2 of the shield experience.
>
>
> On 09/18/2018 11:45 PM, Michael wrote:
>> My basic configuration is the shield is plugged into a yamaha 
>> receiver and the receiver then drives the TV.  Speaker config is 5.1
>>
>>
>> Under the shield settings for video/audio advanced:
>>
>> Surround auto
> I found before that I had to set Surround to "Always" for it to work. 
> However Surround "Auto" now works for me, but I prefer to leave it as 
> "Always".
>>
>> stereo upmix off
>>
>> fixed volume yes
>>
>>
>> In MythTV:
>>
>> Dolby Digital yes
>>
>> DTS yes
>>
>> EAC3, TrueHD, and DTS HD are not selectable and I can't even move to 
>> them - not sure why as my receiver supports all three
>>
>>
>> Speaker config is 5.1
>>
>> Upconvert stereo to 5.1 is yes, but I tried both ways
> Preferably disable this.
>>
>> Use internal controls no
>>
>>
>> Even going into the test audio section can generate the crackle noise.
>>
>> Oddly, When just testing a single speaker like the left front, the 
>> loud crackle seems to come from the center speaker.   It doesn't 
>> matter which speaker is tested, the large crackle comes from the 
>> center ( I believe ).    If I test all, I get the loud crackle and 
>> then it proceeds around the other speakers without issue.
>>
>>
>> Oddly, this configuration was all working fine until a week ago or so 
>> and the only change I can think of was the Shield update.
>>
> Which update was this? I just received notification today of 7.1 
> update but I did not apply it yet. I am still on 7.0.2.
>
> I did find that setting fixed volume off on teh shield prduces the 
> crackle if I adjust volume, so I always leave it as fixed volume.
>
> My setup is shield to TV, and TV digital out to receiver. My receiver 
> does not support hdmi, but tjhe audio gets passed through to the 
> optical output. The receiver confirms via display that it is decoding 
> Dolby Digital.
>

Hi Peter,


I spent some time playing with this tonight.   I tried all of the 
settings you mentioned about and I still am having the crackly sound 
from the center regardless of what speaker is actually playing the the 
start of a video or after seeking forward.


I am at a loss.    How can I get the logs from the frontend to see if 
there is something obvious?


The update I was referring to was the 7.1 update.   I applied it around 
7-10 days ago which is about the time this started. Unfortunately, I 
can't say for certain thats when it started, but its the only thing I 
can think of that changed.


Michael





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