Subject: Re: [linux-audio-dev] Reborn
From: Ingo Oeser (ingo.oeser_AT_informatik.tu-chemnitz.de)
Date: Tue Aug 20 2002 - 09:36:40 EEST
Hi Kjetil,
On Mon, Aug 19, 2002 at 02:42:54PM +0200, Kjetil S. Matheussen wrote:
> Here are some code from ceres to play:
Which is wrong in some places.
>
> struct JackPlayChannel{
> jack_port_t *output_port;
> sample_t buffer[BUFFERSIZE];
> };
>
> struct Jackplay{
> struct JackPlayChannel jpc[4];
> jack_client_t *client;
> struct FFTSound *fftsound;
These four ints must be some kind of atomic variables, to make it work.
> int writeplace;
> int readplace;
> int buffersize;
> int unread;
> };
> /* Consumer */
>
> int jackprocess (nframes_t nframes, void *arg){
> int ch,i;
> struct Jackplay *jackplay=(struct Jackplay *)arg;
> int numch=jackplay->fftsound->samps_per_frame;
> sample_t *out[numch];
>
> for(ch=0;ch<numch;ch++){
> out[ch]= (sample_t *) jack_port_get_buffer (jackplay->jpc[ch].output_port, nframes);
> memset(out[ch],0.0f,nframes*sizeof(sample_t));
This doesn't work and isn't needed. The second argument will be
intepreted as a byte. You also filling the buffer all the time,
so zero initialisation is not necessary.
> }
>
> for(i=0;i<nframes;i++){
> if(jackplay->unread==0) break;
>
> for(ch=0;ch<numch;ch++){
> out[ch][i]=jackplay->jpc[ch].buffer[jackplay->readplace];
> }
> jackplay->unread--;
>
> jackplay->readplace++;
> if(jackplay->readplace==jackplay->buffersize){
> jackplay->readplace=0;
> }
> }
>
> return 0;
> }
>
>
> /* Providor */
>
> void JackWritePlay(
> struct FFTSound *fftsound,
> void *port,double **samples,int num_samples
> )
> {
> struct Jackplay *jackplay=(struct Jackplay *)port;
>
> int i,ch;
>
> for (i=0; i<num_samples; i++) {
> while(jackplay->unread==jackplay->buffersize){
> usleep(128);
> }
> for (ch=0; ch<fftsound->samps_per_frame; ch++){
> jackplay->jpc[ch].buffer[jackplay->writeplace]=(sample_t)samples[ch][i];
> }
> jackplay->unread++;
> jackplay->writeplace++;
> if(jackplay->writeplace==jackplay->buffersize){
> jackplay->writeplace=0;
> }
> }
> }
But for pseudocode all of this is ok ;-)
Regards
Ingo Oeser
-- Science is what we can tell a computer. Art is everything else. --- D.E.Knuth
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