[fnac]

Hi,
I have a problem and it's soon driving me mad.
When watching movies with DTS sound, i get dropouts every now and then, they happen very random and last for approx 0,1-0,3sec or so.
This does NOT happen with other audio formats like AC3 etc.
It also doesn't happen when using my ATV2 or Ouya XBMC with the exact same movie(s) and hookup/setup.

My connection is Rasp>LG TV>Yamaha Receiver.
Now, I know this isn't ideal setup, but my receiver don't have HDMI so I need to go thru LG TV that passes on the audio via TOS link.

If i switch off "DTS capable receiver" in XBMC the sound is output like PCM and works fine. Also when sending out DTS passthrough, my LG TV decodes it to 2channel sound in the TV itself it with no dropouts, by my receiver gets dropouts.

Again, if the same setup had not worked flawlessly with my ATV2 or Ouya, I would've blamed the TV/Reciever combo, but it does work fine with the other 2 so I guess it must have something to do with the Raspberry PI.


I've tried the following so far
- 2 different Raspberrys
- all builds/versions I could find inlucding rbej's testbuilds, nightlys, xbian/rasp/openelec
- editing the config.txt with different values for HDMI, f.x hdmi_force_edid_audio=1 etc. (But perhaps not all combinations there is..)
- new power supplies, new HDMI cables
- debug log in xbmc shows nothing when the dropouts happens
- i've read all threads in different forums (there's been a few, but often in those threads both DTS and AC3 gives dropouts)

I really want to use raspberry pi instead of ATV2 since it does 1080p and has some really nice builds

so if anyone can give me any hint on what to do, I would be very grateful.
thank you

other treads with similar issues i've found
http://forum.xbmc.org/showthread.php?tid=164260&page=3
http://forum.xbmc.org/showthread.php?tid=164751&page=3
http://www.raspberrypi.org/phpBB3/viewto...28&t=19852
http://raspberrypi.stackexchange.com/que...in-raspbmc

[popcornmix]

No real idea. If the TV (and the vast majority of other users) can decode the stream then it suggests the receiver is at best fussy (and at worst buggy).

There's a couple of option that could have an effect:
settings/video/playback and "Adjust display refresh rate to match video" and "Sync playback to display"

I'd also try config_hdmi_boost from:
http://elinux.org/R-Pi_Troubleshooting#I...VI_monitor
(although the fact the TV can decode the audio makes that less likely to help).

[fnac]

thanks for quick reply
I agree but can HDMI signal be "different" on Rasp compared to fx ATV2? one would thought that HDMI DTS signal would somehow be the same..

i forgot to mention that i've already tried all combos of "adjust display rate". Someone in another thread was helped with OFF but for me any combos of settings in that page makes a difference

anyway, I'll test a little more with hdmi_boost and see if that makes any difference.

[mike7]

I have the same issue with DTS passthrough with directly connected receiver, it's discussed in raspbmc forum http://forum.stmlabs.com/showthread.php?tid=10272
Raspbmc backport4 helped a bit, but I still noticing some small dropouts.

Will test with last September build later today

[Elysium.NZ]

I also have exactly the same problem as the OP. In my case the Pi is connected directly to the HDMI-1 on a Samsung HTE-6750W. I also have tried numerous configurations, cables and settings. No matter what I've tried DTS streams drop out intermittently for about 1 second. There is no rhyme nor reason to when they occur but I'd say I'd get 1 or 2 of these interruptions every 5 minutes or so. I'd be happy to install a diagnostic build (any distribution, so far can reproduce on both OpenElec and Xbian) if someone was willing to work on a solution. I've gone backwards and forwards on both release platforms including the latest nightly builds of OpenElec.

[fnac]

tested a few more devices since last time with same setup HDMI OUT > LG TV > LGTV Optical out > Yamaha receiver Optical Input.

here are the results..

AppleTV2 DTS passthrough = OK
Ouya DTS Passthrough = OK
Laptop PC DTS Passthrough = OK
Desktop PC DTS Passthrough = OK
Raspberry (all builds/versions tested so far) DTS Passthrough = DROPOUTS

I had a suspicion that i could have something to do with CEC which only Raspberry has of my tested units, but i turned it off in Raspberry and still same results.

judging from my test I have a really hard time believing that it has something to do with my TV and or Receiver..
so back to square one again.

[Crowley]

Also having the same problem as the OP. The common element is the LG TV.

I'm using RasPi -> TV via HDMI (LG 47LA740V) -> AMP via HDMI/ARC (Onkyo tx-nr616)

Tried various RaspBMC and OpenElec builds, having the same issue with them all. Not having the problem with other HDMI sources although I haven't tested quite as thoroughly as Fnac above :-)

[Jelf10]

Just started getting this problem since October update.
Also have LGTV and using optical out to receiver.
Dropouts aren't by the tv and has been fine since I've been using the pi. Months maybe a year.
Lastly couple of updates seem to have caused more issues than fixed

[DBMandrake]

Completely off the wall suggestion here, but have you tried something like config_hdmi_boost=4 ?

The default signal (voltage) level of the HDMI output on the Raspberry Pi seems to be a bit marginal, I've had problems even with a 3 metre HDMI to DVI cable to a particular PC monitor where it would intermittently show HDMI "speckle" as shown here:

"Interference visible on a HDMI or DVI monitor"

http://elinux.org/R-Pi_Troubleshooting#I...VI_monitor

The speckle is caused by high bit error rates over the HDMI cable that are beyond the ability of error correction to correct.

I'm not sure whether the audio is multiplexed over the same data lines as the video but if it is it stands to reason that a high error rate may cause audio problems like dropouts too.

config_hdmi_boost increases the voltage levels on the HDMI output, so if the high error rate is due to the low voltage it may help.

Another thing to try would be a better power supply. The previous Raspberry Pi I set up for a friend had a tendency to spontaneously reboot when using the menus in XBMC, even though it was a 5 volt "2 amp" supply.

When I got a Pi for myself, knowing how sensitive they are to low/unstable voltage I chose this power supply:

https://www.modmypi.com/raspberry-pi-acc...odle-cable

It's a well regulated 5.25v supply - the extra 0.25v is (just) within the acceptable USB spec, and can help make up for voltage drop issues that Pi's are very sensitive to. Under full load when overclocked I measure 5.12 volts between TP1 and TP2 with this supply.

I've run Raspbmc on mine with "super" profile overclocking (950Mhz) on a Samsung 16GB class 10 card and it has been absolutely rock stable over many days, not a single reboot or crash, and I put that down largely to the power supply.

Edit: just noticed I missed popcornmix's suggestion to use config_hdmi_boost... sorry guys!

[plinkyplonky]

fnac, you probably want the kernel fix that popcornmix has implemented recently, which fixes DTS passthrough dropouts. Eventually it will go into the standard XBMC build.

Check it out here:
http://www.raspberrypi.org/phpBB3/viewto...28&t=19852