[alsa-devel] [PATCH] ascenario: Add scenario support to alsa-lib

Liam Girdwood lrg at slimlogic.co.uk
Thu Oct 1 15:54:00 CEST 2009

On Thu, 2009-10-01 at 08:39 -0500, pl bossart wrote:
> +/** QOS
> + *
> + * Defines Audio Quality of Service
> + */
> +#define SND_QOS_HIFI                   0
> +#define SND_QOS_VOICE                  1
> +#define SND_QOS_SYSTEM                 2
> My $0.02 comment is that I don't know what QOS entails. I have no
> issue with all the other defines, but this one isn't quite clear.
> What exactly is supposed to happen if I set the QOS to voice? A lower
> SNR for voice? A lower latency for voice with a lower group delay? A
> lower oversampling ratio? An optimized routing for voice? All of the
> above?

It's only about power usage here. i.e. run CODEC with slower clocks internally, may lower SNR.

So maybe


> +#define SND_SCN_PHONECALL_HANDSET      "phonecall handset"
> +#define SND_SCN_PHONECALL_HEADSET      "phonecall headset"
> +#define SND_SCN_PHONECALL_BLUETOOTH    "phonecall bluetooth"
> +#define SND_SCN_PHONECALL_IP           "phonecall ip"
> Same here, this is ambiguous, you can have an IP call over bluetooth.
> Which scenario would you use then?
> I guess if you want the scenarios to be used by apps in a portable
> way, a clearer definition of each scenario is probably needed?

These are ambiguous, I guess we need to have

#define SND_SCN_PHONECALL_GSM_HANDSET "phonecall gsm handset"
#define SND_SCN_PHONECALL_BT_HANDSET "phonecall bt handset"
#define SND_SCN_PHONECALL_IP_HANDSET "phonecall ip handset"

For gsm, bluetooth and VOIP handset phone calls respectively.



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