Re: [Protux-devel] Open Task

[Martin Herren]

Luciano Giordana wrote:

> You dont need to go so far, I have a standard routine using libmustux (which 
> makes it pretty simple)
> take a look (please reihard, save this example for libmustux documentation )
>
>        int busId=0; // or 1 or 2, and so on.. must be any valid busId.
>         int channels =  MustuxAudioDeviceMapper::STEREO;
>         int rate=44100;
>         int bitDepth = 16;
>        if (MustuxAudioDeviceMapper::open_bus_out(busId, rate, bitDepth)<0)
>                 {
>                 // error
>                 }
>        buf = MustuxAudioDeviceMapper::get_bus_out_transfer_buffer(busId, 
> channels);
>         bufSize = MustuxAudioDeviceMapper::get_bus_out_transfer_size(busId);
>
>        while (!feof(file))
>                {
>                fread(buf,1,bufsize,file);
>                int r=MustuxAudioDeviceMapper::bus_out_transfer(bus);
>                if (r==MustuxAudioDeviceMapper::ERROR_UNDERRUN)
>                        {
>                         // Error...
>                        }
>                }
>
>         MustuxAudioDeviceMapper::close_bus_out(busId);
>
> any doubts, please feel free to ask

thanks... got a first playback working, not commited yet as there are 
still a lot of error conditions to check.
I don't use fread, but PrafFile::get_fragment(), i think that's why this 
function is there ;-)

Just a question: what happens at the end of the praf clip, when fread() 
(or get_fragment()) reads less than bufsize. That would mean that the 
end of the buffer contains old audio data, which would lead to a 'noisy 
click' at the end of playback (at the edge of the new and the old data). 
Or i am completely wrong ?
I think the return value of fread should be checked, and given as an 
argument to bus_out_transfer().... or is this problem handled somewhere 
else ? Like padding the praf audio data with zeros to achieve and audio 
size which is a multiple of bufsize ? (But bufsize depends on the 
hardware, no ?).

thanks

/Martin