Re: [Discuss-gnuradio] Re: Some questions about audio output and under-runs on a custom block....

[Eric Blossom]

On Tue, Sep 08, 2009 at 08:16:07AM +1000, Steve Glass wrote:
> Hi,
> 
> I've got my custom block producing mono audio at 8KS/s which I am sending to
> an audio_sink(8000, "plughw:0,0") and have some questions.
> 
> First question: what is the range of values that each output sample can
> assume before clipping? Since they're floats I am assuming its -1.0 .. +1.0.
> Is that correct?

Yes.

> Second question: for now I am providing audio silence but get a constant
> stream of aU events displayed on the console. I am a little bothered by that
> because general_work always produces exactly what its asked for:
> 
> int
> custom_block_ff::general_work(int nof_output_items, gr_vector_int&
> nof_input_items, gr_vector_const_void_star& input_items,
> gr_vector_void_star& output_items)
> {
>       // handle inputs
>       ...
> 
>       // produce audio (silence for the time being)
>       consume(0, nof_input_items[0]);
>       float *out = reinterpret_cast<float*>(output_items[0]);
>       fill(out, out + nof_output_items, 0.0);
>       return nof_output_items;
> }

Is there a rate limiting block upstream of custom_block_ff, such as a
usrp or usrp2?

Eric