[alsa-devel] Proper way to set SCMS copy prohibited bits on IEC958 S/PDIF

Rene Herman rene.herman at keyaccess.nl
Thu Jul 31 02:09:46 CEST 2008

On 31-07-08 02:03, Andrew Paprocki wrote:

> On Wed, Jul 30, 2008 at 8:01 PM, Rene Herman <rene.herman at keyaccess.nl> wrote:
>> On 30-07-08 22:37, Andrew Paprocki wrote:
>>> I briefly checked the code for the Delta1010 (ice1712) to see if there
>>> was a way from user space to force the SCMS copy prohibited bits on in
>>> the S/PDIF stream. I see the driver initializes the bits to 0. Is
>>> there already a way to do this from user space, or would I have to
>>> modify the driver to force them on (or use a module parameter)?
>> I can't try this myself right now, but try "man iecset".
> I actually found this code as well: http://www.cs.tut.fi/~ik/mpegspdif/output.c
> It appears you can set the bits when opening the card by using a
> device string like this:
> sprintf(devstr, "iec958:AES0=0x%x,AES1=0x%x,AES2=0x%x,AES3=0x%x",
> s[0], s[1], s[2], s[3]);
> I'll look into both methods.

Yes, noticed that to (in /usr/share/alsa/pcm/iec958.conf) but couldn't 
tell you what the %x were, so "iecset" seemed like better advice...


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