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Passthrough of DTS-HD MA & TrueHD stuttering - Printable Version

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Passthrough of DTS-HD MA & TrueHD stuttering - shh - 01-22-2015

Again some problems here with my CuboxTV (quad-core + 1GB RAM):
Passthrough/Bitstreaming of DTS-HD MA & TrueHD is stuttering at playback.
Well, passthrough is working but every few seconds there are some small video frame skips, and also (very) short audio disconnects at the receiver.
No problems, if I deactivate TrueHD and DTS-HD streams. After deactivating both features OpenELEC does this:
TrueHD 5.1 is decoded to 5.1 PCM: perfectly smooth playback (bitstreamed PCM-Multichannel to the receiver)
DTS-HD 6.1 is stripped to core 6.1 DTS-ES: perfectly smooth playback (bitstreamed DTS to the receiver)
While watching stream & buffer sync via pressing o:
- audio, video and stream buffers are perfectly full on playback
- cpu(s) are nearly unused (~5-20%), system is cool (45°C), ...
- video(!) is slowed down, not being const at 24fps. At that point often video/audio frame skips occur

Setup: CuboxTV->HDMI@24fps/23.976fps->Onkyo AVR->HDMI@24fps/23.976fps->TV
AVR & TV are both HDMI 1.3a capable, so bitstreaming DTS-HD and TrueHD should be fine.
Changing audio/video settings like sync-to-video, add/del audio-frames etc. just make things worse, especially audio quality.
I'm using <always> for the driver refresh to sync to TV refresh (against tearing). Other settings don't change anything.

I think it's important to mention again, that video-decoding seems to get too slow here, so that desyncs occur which have to be handled somehow.
The video frame rate is never const at 24.000 or 23.976 but often dropping to ~23.5 or even down to 22fps.
But the slow down of video fps could be a reason because of audio frames that cannot be sent fast enough via HDMI what kodi want's to compensate/sync somehow.
That brought me to wondering about spdif:
I blacklisted the two spdif modules. Primaryly to get rid of the stupid red light on the spdif port... but this didn't switch off the light - it's still constantly red. Sad
BUT this could mean that spdif is still working somewhere, and we all know, that spdif isn't capable of high bitrate streams like TrueHD and DTS-HD. So maybe some chipset setting is limiting HDMI audio passthrough to spdif data rates?! :blink: How do I get kodi to handle high audio data rates?

Any other suggestions?
My network is fast enough already (1 Gbps reduced to something CuboxTV is capable - the NIC driver does this via flow control). Switching to 100MBit doesn't help either. This all doesn't seem to be a "feeding kodi" problem.
Has somebody else got some experience with this? Perhaps some hints to adjust some buffers?

Log attached of: playing a LotR.mkv with DTS-HD MA 6.1ch with stuttering

Passthrough of DTS-HD MA & TrueHD stuttering - Peter911 - 01-25-2015


this is exactly my problem too...

Audio Dropouts with frame stutterin while playing HD-Audio Content and only 24.000 fps instead of native 23.976 fps.

anybody else? A solution would be very great!

Thanks in advance.
BR Peter

Passthrough of DTS-HD MA & TrueHD stuttering - sh-hedge - 02-12-2015

Same Problem here.
My Hardware should be capable of playing TRUEHD and Atmos sound. (Denon X4100 + HTPC with AMD A4-5000)
Video runs smoothly, but sound stutters when playing TrueHD, Dolby Atmos or DTSHD MA sound. Every other formats plays well.
I have another client (HDI Dune smart b1) wich works fine. So I'm sure it must be the HTPC and/or openelec system.

Info: Canging video settings (frame rate, resolution) changes sound format recognized by the AVR

Passthrough of DTS-HD MA & TrueHD stuttering - wwschoof - 03-27-2015

How do you get to see the passthrough settings for TrueHD and DTS-HD? I'm running a cubox i4 with OE 5.0.6 on a HK AVR171. View mode is set to Expert level, passthrough device is imx-hdmi-soc, but there is only passthrough for DTS and Dolby Digital :-( I reinstalled OpenELEC, but nothing changed. Are there any tweaks to make this work?

Passthrough of DTS-HD MA & TrueHD stuttering - wwschoof - 05-09-2015

What else can I do?

cubox:~ # aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: imxhdmisoc [imx-hdmi-soc], device 0: i.MX HDMI Audio Tx hdmi-hifi-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: imxspdif [imx-spdif], device 0: S/PDIF PCM snd-soc-dummy-dai-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0

cubox:~ # cat /proc/asound/version
Advanced Linux Sound Architecture Driver Version k3.14.36.

i tried to set dtshdpassthrough and truehdpassthrough in guisetting.xml to true manuelly but without success.

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