anssi.hannula at iki.fi
Tue Jun 14 20:09:43 CEST 2011
On 14.06.2011 15:47, ajay khandelwal wrote:
> Hi All,
I've worked with IEC61937, but I'm no ALSA expert, so I hope others
correct me if I'm wrong.
> I have to develop driver for SPDIF output of my board connected to HDMI.
> I'm not sure for following (specially IEC61937)
> 1) How should driver know if it is compressed audio or plain pcm
You can look at the bit 1 (0x02) of AES0 IEC958 channel status.
The driver generally provides IEC958 controls:
That are then used via hooks in "foo.pcm.hdmi.0" (or "foo.pcm.iec958.0"
for non-hdmi) definition in /usr/share/alsa/cards/foo.conf (look at
existing drivers for examples).
Applications can then set these flags by e.g. opening the ALSA audio
device as "hdmi:AES0=0x06,AES1=0x82" etc.
> 2) Is their any plugin available for IEC61937, I could see only for IEC958
> 3) Who should create burst preamble, some plug in or driver.
Currently they are created by the applications themselves.
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