Testing HD Audio passthrough


Tags: HD-audio ALSA linux

Test files are available at http://samples.mplayerhq.hu/A-codecs and also http://www.avenard.org/files/media/mediatest/audiotest/HDAUDIO/Passthrough/

In the xbmc logs when attempting to play a file with DTS-MA audio, the following was logged:

20:21:16 T:140571519944448    INFO: CAESinkALSA::Initialize - Opened device "hdmi:CARD=Generic,DEV=0,AES0=0x06,AES1=0x82,AES2=0x00,AES3=0x0e"

I therefore tried playing the test file with:

aplay -D hdmi:CARD=Generic,DEV=0,AES0=0x06,AES1=0x82,AES2=0x00,AES3=0x0e -c8 -fs16_le -r192000 testi.dtshd.anssi1.ma-71-24.spdif 

to no avail.

Playing back a standard Dolby Digital file via mplayer:

mplayer -ac hwac3 -ao alsa:device=hw=0.3 /home/ed/Downloads/Broadway-5.1-48khz-448kbit.ac3

Attempt at playing back DTS-HD file via mpv:

mpv --ad-spdif-dtshd=yes -ao alsa:device=[hw:0,3] /home/ed/Downloads/hd_dts_animated_logo_lossless.m2ts

Testing multichannel output:

speaker-test -D hdmi -c 8 -m FL,FC,FR,RR,RRC,RLC,RL,LFE

When specifying the sampling rate as 192000 as per http://mailman.alsa-project.org/pipermail/alsa-devel/2013-September/066691.html however, get no output.

This is important as when doing HD audio passthrough, as the compressed non-audio data is sent over the device as if it is an 8 channel 192khz audio signal.

Details of the audio codec can be got via

cat /proc/asound/card0/codec#0