[mythtv-users] How Myth "sees" an audio device

Pieter De Wit pieter at insync.za.net
Tue Apr 17 00:21:30 UTC 2012



On Tue, 17 Apr 2012, Jean-Yves Avenard wrote:

> On 17 April 2012 09:21, Pieter De Wit <pieter at insync.za.net> wrote:
>> Hi All,
>>
>> (JYA will most likely answer this one :) )
>>
>> Is there a command line command that I can run to see what cap. my audio
>> device has ? I have a Samsung HD6750w directly connected to my Nvidia GT430
>> via HDMI. Yet Myth says it doesn't do TrueHD etc.
>
> What text *exactly* do you see in Setup -> Audio at the bottom of the screen?
> like described there:
> http://www.mythtv.org/wiki/User_Manual:HDAudioPassthrough
>
> Myth uses the ALSA interfaces to browse all available audio devices,
> same as what aplay -L does.
>
> When it comes to reading what's connected to the HDMI interface, this
> is done by reading the ELD (EDID like Data) from the device. If it can
> be retrieved, you will see the name of the device connected, and what
> audio features it reports (AC3, DTS, TrueHD etc...)
>
> you can see that information either in the kernel log (dmesg will show
> something like:
> [   38.785978] HDMI status: Codec=0 Pin=5 Presence_Detect=1 ELD_Valid=1
> [   40.703534] HDMI: detected monitor SP32
> [   40.703537]  at connection type HDMI
> [   40.703541] HDMI: available speakers: FL/FR LFE FC RL/RR RC FLC/FRC RLC/RRC
> [   40.703546] HDMI: supports coding type LPCM: channels = 8, rates =
> 32000 44100 48000 96000 176400 192000 384000, bits = 16 20 24
> [   40.703551] HDMI: supports coding type AC-3: channels = 6, rates =
> 32000 44100 48000 96000 176400 192000 384000, max bitrate = 1536000
> [   40.703556] HDMI: supports coding type DTS: channels = 6, rates =
> 32000 44100 48000 96000 176400 192000 384000, max bitrate = 1536000
> [   40.703560] HDMI: supports coding type DTS-HD: channels = 8, rates
> = 32000 44100 48000 96000 176400 192000 384000
> [   40.703564] HDMI: supports coding type E-AC-3/DD+ (Dolby Digital
> Plus): channels = 8, rates = 32000 44100 48000 96000 176400 192000
> 384000
> [   40.703568] HDMI: supports coding type MLP (Dolby TrueHD): channels
> = 8, rates = 32000 44100 48000 96000 176400 192000 384000
>
> you can also see it by doing something like:
> cat /proc/asound/card*/eld#*.0
>
> If you run mythfrontend with -v audio ; that information will be shown
> in the log.
>
> You must be using ALSA 1.0.25 or later (don't use the 1.0.25 tarball
> found on the alsa web site, it's buggy with nvidia cards, get the git
> version
>
>> I am running a Ubuntu system updated to 12.04 with the myth repos.
>
> As far as I can tell, 12.04 ships with a kernel containing ALSA 1.0.24
> ; and as such won't allow to retrieve the ELD value, so myth won't be
> able to detect what your amp support.
> _______________________________________________
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> mythtv-users at mythtv.org
> http://www.mythtv.org/mailman/listinfo/mythtv-users
>
Hi JYA,

I have the following for alsa:

ii  alsa-base                              1.0.25+dfsg-0ubuntu1 
ALSA driver configuration files
ii  alsa-utils                             1.0.25-1ubuntu5 
Utilities for configuring and using ALSA

# cat /proc/asound/card*/eld#*.0
monitor_present		0
eld_valid		0
monitor_present		1
eld_valid		1
monitor_name		SAMSUNG

connection_type		HDMI
eld_version		[0x2] CEA-861D or below
edid_version		[0x3] CEA-861-B, C or D
manufacture_id		0x2d4c
product_id		0x4fb
port_id			0x20000
support_hdcp		0
support_ai		0
audio_sync_delay	0
speakers		[0x4f] FL/FR LFE FC RL/RR RLC/RRC
sad_count		4
sad0_coding_type	[0x1] LPCM
sad0_channels		2
sad0_rates		[0x6e0] 32000 44100 48000 96000 176400
sad0_bits		[0xe0000] 16 20 24
sad1_coding_type	[0x1] LPCM
sad1_channels		8
sad1_rates		[0x6e0] 32000 44100 48000 96000 176400
sad1_bits		[0xe0000] 16 20 24
sad2_coding_type	[0x2] AC-3
sad2_channels		6
sad2_rates		[0xe0] 32000 44100 48000
sad2_max_bitrate	640000
sad3_coding_type	[0x7] DTS
sad3_channels		6
sad3_rates		[0xe0] 32000 44100 48000
sad3_max_bitrate	1536000
monitor_present		0
eld_valid		0
monitor_present		0
eld_valid		0

I can't recall exactly what myth shows on the screen. I do remember 
"SAMSUNG connected via HDMI" and DTS and two others (I think it's the 
two/three on the left of the check box list in the audio config screen)

Apr  8 11:45:17 media kernel: [   60.917860] HDMI hot plug event: Codec=1 
Pin=5 Presence_Detect=1 ELD_Valid=0
Apr  8 11:45:17 media kernel: [   60.924046] HDMI status: Codec=1 Pin=5 
Presence_Detect=1 ELD_Valid=0
Apr  8 11:45:17 media kernel: [   60.938266] HDMI hot plug event: Codec=1 
Pin=5 Presence_Detect=0 ELD_Valid=1
Apr  8 11:45:17 media kernel: [   60.944041] HDMI status: Codec=1 Pin=5 
Presence_Detect=1 ELD_Valid=1
Apr  8 11:45:18 media kernel: [   61.716040] HDMI: detected monitor 
SAMSUNG
Apr  8 11:45:18 media kernel: [   61.716044]       at connection type HDMI
Apr  8 11:45:18 media kernel: [   61.716051] HDMI: available speakers: 
FL/FR LFE FC RL/RR RLC/RRC
Apr  8 11:45:18 media kernel: [   61.716060] HDMI: supports coding type 
LPCM: channels = 2, rates = 32000 44100 48000 96000 176400, bits = 16 20 
24
Apr  8 11:45:18 media kernel: [   61.716070] HDMI: supports coding type 
LPCM: channels = 8, rates = 32000 44100 48000 96000 176400, bits = 16 20 
24
Apr  8 11:45:18 media kernel: [   61.716078] HDMI: supports coding type 
AC-3: channels = 6, rates = 32000 44100 48000, max bitrate = 640000
Apr  8 11:45:18 media kernel: [   61.716086] HDMI: supports coding type 
DTS: channels = 6, rates = 32000 44100 48000, max bitrate = 1536000
Apr  8 11:45:19 media kernel: [   63.114002] init: mdd main process (1906) 
terminated with status 111
Apr  8 11:45:19 media kernel: [   63.114051] init: mdd main process ended, 
respawning
Apr  8 11:45:26 media kernel: [   69.756140] HDMI hot plug event: Codec=1 
Pin=5 Presence_Detect=1 ELD_Valid=0
Apr  8 11:45:26 media kernel: [   69.764046] HDMI status: Codec=1 Pin=5 
Presence_Detect=0 ELD_Valid=0
Apr  8 11:45:26 media kernel: [   69.771472] HDMI hot plug event: Codec=1 
Pin=5 Presence_Detect=1 ELD_Valid=0
Apr  8 11:45:26 media kernel: [   69.776042] HDMI status: Codec=1 Pin=5 
Presence_Detect=1 ELD_Valid=0
Apr  8 11:45:26 media kernel: [   69.788310] HDMI hot plug event: Codec=1 
Pin=5 Presence_Detect=0 ELD_Valid=1
Apr  8 11:45:26 media kernel: [   69.796025] HDMI status: Codec=1 Pin=5 
Presence_Detect=1 ELD_Valid=1
Apr  8 11:45:26 media kernel: [   70.580057] HDMI: detected monitor 
SAMSUNG
Apr  8 11:45:26 media kernel: [   70.580060]       at connection type HDMI
Apr  8 11:45:26 media kernel: [   70.580065] HDMI: available speakers: 
FL/FR LFE FC RL/RR RLC/RRC
Apr  8 11:45:26 media kernel: [   70.580071] HDMI: supports coding type 
LPCM: channels = 2, rates = 32000 44100 48000 96000 176400, bits = 16 20 
24
Apr  8 11:45:26 media kernel: [   70.580076] HDMI: supports coding type 
LPCM: channels = 8, rates = 32000 44100 48000 96000 176400, bits = 16 20 
24
Apr  8 11:45:26 media kernel: [   70.580081] HDMI: supports coding type 
AC-3: channels = 6, rates = 32000 44100 48000, max bitrate = 640000
Apr  8 11:45:26 media kernel: [   70.580086] HDMI: supports coding type 
DTS: channels = 6, rates = 32000 44100 48000, max bitrate = 1536000

Lookung at that, it seems that the AMP is not advertising the correct 
support, like TrueHD etc ?

Thanks !

pieter


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