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Clicks, pops, stuttering on AC3 playback

Posted: 12 Apr 2016, 19:23
by CallClear
Hi There. I discovered today that anytime I play any media with a Dolby Digital track, the audio sounds really bad. A link to my log file is here:

http://pastebin.com/ThaLkYdc

Playback starts around 11:50:27. I ran it for around 15 seconds where there was all the clicking and popping...but it was still understandable. I then paused it and changed to passthrough (I have a capable receiver). That was just complete static noise. I then turned off passthrough and the clicking and popping resumed.

Any ideas? Is there a setting I'm missing somewhere?

Appreciate any help. Thanks!

Re: Clicks, pops, stuttering on AC3 playback

Posted: 12 Apr 2016, 22:45
by CallClear
I totally forgot to mention... To be clear, I'm not concerned about the passthrough issue. I know (or at least I've read) that it is a common issue among all apps on the aTV4. Especially with Denon receivers...which lucky me, I have. I just included it in case you wanted to see the log of someone who had the issue. I'm only interested in getting the AC3 decoding issue figured out.

Re: Clicks, pops, stuttering on AC3 playback

Posted: 13 Apr 2016, 01:13
by davilla
what are your tvOS audio settings ?

Re: Clicks, pops, stuttering on AC3 playback

Posted: 13 Apr 2016, 02:37
by CallClear
Surround sound is Best Quality Available. Reduce Loud Sounds is off. Audio mode is Auto.

Re: Clicks, pops, stuttering on AC3 playback

Posted: 14 Apr 2016, 00:50
by CallClear
So I've done a little more playing around with the Apple TV settings and still getting no joy.

I tried swapping out the HDMI cable. No change.

I tried changing Audio Mode to 16 bit. That made the stuttering even worse.

I tried changing from Best Quality Available to Dolby Digital. That worked (no stuttering or popping) and showed Dolby D on my receiver...so I'm pretty sure that would mean Apple TV is taking the LPCM decoded by MrMC, encoding it back to AC3, then passing it to the receiver where it is again decoded. But curiously, if the clicking and popping were coming from MrMC, I would think that would be reflected in Apple TV's encoding back to AC3? ...But I'm the first to admit that I really have no clue how this sorcery works...

(Side note, when I played a DTS movie with this method in MrMC, the center channel was coming out of the right rear speaker...odd, but I'm not really sure why anyone would ever want to do this..)

Anyways, I'm telling you all of this so you know what I'm doing to troubleshoot....assuming anyone cares. It is odd that it sounds like this is only be happening to me. Do you think maybe I got a defective Apple TV? I'm still up for suggestions if anyone has any.

Re: Clicks, pops, stuttering on AC3 playback

Posted: 14 Apr 2016, 04:15
by davilla
nah, your atv4 is fine.

what receiver ?

could be our channel routing is wrong, or the video content you played was wrong. seems fine here and we do test channel routing but there are 10e6 different combinations so we can't test them all.

Re: Clicks, pops, stuttering on AC3 playback

Posted: 14 Apr 2016, 05:18
by CallClear
It is an AVR-S510BT. I updated the firmware yesterday to see if that had any effect but didn't.. :(

Re: Clicks, pops, stuttering on AC3 playback

Posted: 14 Apr 2016, 19:13
by CallClear
More troubleshooting results for your pleasure... :)

I have a 5.1 speaker configuration but for kicks, I changed MrMC to 5.0. For both configurations, the receiver reported 3/2/.1. There was NO popping and stuttering with the 5.0 configuration and there was definitely audio reporting from the sub-woofer.

I was pretty stoked...until I realized that the center channel was coming out of the left rear speaker, no audio was coming out of the right rear speaker, and I'm not sure what was coming out of the center channel. That made me realize I'd never checked to see if audio was reporting correctly with the 5.1 setup...I was always just focused on the noise. Sure enough, even in 5.1, the center channel is coming out of the left rear speaker.

Again, just reporting to you in case this helps anything on your end...

Re: Clicks, pops, stuttering on AC3 playback

Posted: 18 May 2016, 14:53
by CallClear
I just wanted to report that AC3 decoding is working great in 2.2.

Passthrough still isn't working for me (both Dolby or DTS) but I'm just happy to have an option for multi-channel surround now. :D

Thanks for all your hard work!