[mythtv-users] Bluray DTS passthrough doesn't work

Paul B. Henson henson at acm.org
Mon Mar 17 04:35:20 UTC 2014


I'm setting up a new 0.27 myth system, and was testing DVD and Bluray
rips in mkv containers. My system has a receiver hooked up via HDMI that
supports pretty much all the codecs, and I'm configuring mythtv for
passthrough.

When I play a DVD rip with the internal player, the receiver show Dolby
Digital, and it works great.

When I try to play a Bluray rip, there's no sound at all and the
receiver is just blinking like it's waiting for sound or trying to
figure out what it's seeing.

If I play the same Bluray rip with mplayer (mplayer -ao
alsa:device=hw=1.9 -afm hwac3), it works fine, and the receiver shows
DTS, so the hardware is definitely capable.

I have mythfrontend configured to use ALSA:default, which is labeled as
"TX-NR609 connected to HDMI", and shows support for "up to 7.1 (LPCM,
AC3, DTS, DSD, E-AC3, DTS-HD, TrueHD)", and I have all the passthrough
checkboxes clicked. If I flip through the other options, there's one
specific to the HDMI device which shows the same details as the default,
as that's what the default points to.

In the log when playing the DVD, it shows:

ALSA lib conf.c:4694:(snd_config_expand) Unknown parameters
AES0=6,AES1=0x82,AES
2=0x00,AES3=0x01
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM
default:AES0=6,AES1=0x82
,AES2=0x00,AES3=0x01
2014-03-16 15:47:18.814266 N  AudioPlayer: Enabling Audio
2014-03-16 15:47:18.825811 I  AFD: codec AC3 has 6 channels
2014-03-16 15:47:18.826159 I  AFD: Opened codec 0x56a0760, id(AC3)
type(Audio)
2014-03-16 15:47:18.826184 I  AFD: codec AC3 has 6 channels
2014-03-16 15:47:18.826512 I  AFD: Opened codec 0x56a0f20, id(AC3)
type(Audio)
2014-03-16 15:47:18.826520 I  AFD: codec AC3 has 2 channels
2014-03-16 15:47:18.826850 I  AFD: Opened codec 0x56a16e0, id(AC3)
type(Audio)
2014-03-16 15:47:18.826878 I  AFD: Opened codec 0x56a1ec0,
id(DVD_SUBTITLE) type
(Subtitle)
2014-03-16 15:47:18.826901 I  AFD: Opened codec 0x557b300,
id(DVD_SUBTITLE) type(Subtitle)
2014-03-16 15:47:18.826920 I  AFD: Opened codec 0x557bce0,
id(DVD_SUBTITLE) type(Subtitle)
2014-03-16 15:47:18.831331 I  AFD: Opened codec 0x569ffa0,
id(MPEG2VIDEO) type(Video)
2014-03-16 15:47:18.831991 I  AOBase: Opening audio device 'default' ch
2(6) sr 48000 sf signed 16 bit reenc 0
2014-03-16 15:47:18.835067 E  ALSA: Requested 500000us got 341333 buffer
time
2014-03-16 15:47:18.835158 E  ALSA: Try to manually increase audio
buffer with: echo 128 | sudo tee /proc/asound/card1/pcm9p/sub0/prealloc



for the bluray:

2014-03-16 15:48:42.564427 N  AudioPlayer: Enabling Audio
ALSA lib conf.c:4694:(snd_config_expand) Unknown parameters
AES0=6,AES1=0x82,AES
2=0x00,AES3=0x01
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM
default:AES0=6,AES1=0x82
,AES2=0x00,AES3=0x01
2014-03-16 15:48:42.736681 I  AFD: codec DTS has 6 channels
2014-03-16 15:48:42.736818 I  AFD: Opened codec 0x68500c0, id(DTS)
type(Audio)
2014-03-16 15:48:42.736852 I  AFD: codec DTS has 6 channels
2014-03-16 15:48:42.736907 I  AFD: Opened codec 0x6850880, id(DTS)
type(Audio)
2014-03-16 15:48:42.736916 I  AFD: codec AC3 has 6 channels
2014-03-16 15:48:42.737310 I  AFD: Opened codec 0x6851040, id(AC3)
type(Audio)
2014-03-16 15:48:42.737623 I  AFD: Opened codec 0x6851820,
id(HDMV_PGS_SUBTITLE) type(Subtitle)
2014-03-16 15:48:42.737910 I  AFD: Opened codec 0x6852000,
id(HDMV_PGS_SUBTITLE) type(Subtitle)
2014-03-16 15:48:42.742758 I  AFD: Opened codec 0x684f900, id(H264)
type(Video)
2014-03-16 15:48:42.743515 I  AOBase: Opening audio device 'default' ch
8(6) sr 192000 sf signed 16 bit reenc 0
2014-03-16 15:48:42.746538 E  ALSA: Requested 500000us got 21333 buffer
time
2014-03-16 15:48:42.746634 E  ALSA: Try to manually increase audio
buffer with: echo 1536 | sudo tee /proc/asound/card1/pcm9p/sub0/prealloc

Any ideas why AC3 passthrough works, but not DTS?

Thanks...



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