opus - Dec 2013 - playback of opus files using portaudio

I am making a lightweight opus audio player. This is my portaudio callback
function. But i hear a stammering song when i try to play a .opus song
file. Can anybody say what is wrong or provide me link to any code which
can play opus file written in c/c++(light). I tried to see some open
source(vlc opus play) but was unable to follow.

int MyCallback(const void* input,
   void* output,
   unsigned long frameCount,
   const PaStreamCallbackTimeInfo* paInfo,
   PaStreamCallbackFlags paCallbacks,
   void *userData
   )
{
OurData *data=(OurData*) userData;
opus_int16* out=(opus_int16 *)output;
int thisSize=frameCount;
int smpls_decoded;
while (thisSize>0)
{
smpls_decoded=op_read(data->sndFile,out,thisSize,NULL);
out+=data->channels*smpls_decoded;
thisSize-=data->channels*smpls_decoded;
}
  return paContinue;
}
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Akshit Jain wrote:
> I am making a lightweight opus audio player. This is my portaudio
> callback function. But i hear a stammering song when i try to play a
> .opus song file. Can anybody say what is wrong or provide me link to any
> code which can play opus file written in c/c++(light). I tried to see
> some open source(vlc opus play) but was unable to follow.
See opusfile_example.c in the examples/ directory of libopusfile.
On Linux,
   ./opusfile_example foo.opus | aplay
makes a rudimentary player.
> smpls_decoded=op_read(data->sndFile,out,thisSize,NULL);
You're using op_read(), but ignoring the link number. This will do the 
wrong thing on chained files where the number of channels changes 
between links. You can use op_read_stereo() to get a fixed number (2) of 
channels out regardless of the number of channels in each link.

You're also not handling error return values. That should not be a 
problem on properly encoded files, but it is a potential security 
vulnerability, since you're using the return value to do pointer arithmetic.

What do your Pa_OpenStream() parameters look like?