[pulseaudio-discuss] PA_STREAM_ADJUST_LATENCY with Simple API?

[Lennart Poettering]

On Sat, 23.05.09 03:32, Cristian Morales Vega (cmorve69 at yahoo.es) wrote:

> Hi,
> 
> I just wanted to know if there is a way to use the
> PA_STREAM_ADJUST_LATENCY flag using the simple API.
> I see that pa_simple_new() has a parameter for pa_buffer_attr, but no
> for pa_stream_flags_t. Why I would want to specify the server buffer
> size? I only want to specify the size because of the latency, isn't
> that the common case? Perhaps PA_STREAM_ADJUST_LATENCY is the default
> when using the simple API?

Hmm, it currently is not the default. 

However I guess it makes sense to make it the default, even if that
might be considered API breakage. But I guess that kind of breakage
doesn't really count since the usefulness of the attr argument is not
really given without the flag set.

I have now made this the default int PA git.

> The app is a game console emulator. It doesn't needs anything special,
> only a low latency so video and audio are in sync.

Hmm? For audio/video in sync you don't need low latency. All you need
is accurate latency measurements. Which PA provides.

> Right now the code is just an init() function that calls
> pa_simple_new() and a sample() function that does this:
> 
> void sample(uint16_t left, uint16_t right) {
>   if(!device.handle) return;
> 
>   buffer.data[buffer.offset++] = left + (right << 16);
>   if(buffer.offset >= 64) {
>     int error;
>     pa_simple_write(device.handle, (const void*)buffer.data,
> buffer.offset * sizeof(uint32_t), &error);
>     buffer.offset = 0;
>   }
> }
> 
> I would really like to keep the simple API, if I could specify the
> full latency I would not need to touch more than one or two lines.
> But... it is possible?

With the current git version of PA after my little change mentioned
above: yes. Otherwise: no.

Sorry,

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4