Re: [Discuss-gnuradio] Phase errors and expected behavior of in-flight samples when a flowgraph is reconfigured

[Kevin Reid]

On Apr 21, 2014, at 0:53, Alexandru Csete <address@hidden> wrote:
> On Mon, Apr 21, 2014 at 2:31 AM, Kevin Reid <address@hidden> wrote:
>> I've seen three different intermittent misbehaviors in my application which 
>> can be described as parallel signal paths getting out of phase with each 
>> other. (For example, one of them is one stereo audio output channel being 
>> delayed from the other.)
>> 
>> They all seem to occur when the flowgraph is reconfigured (lock, change 
>> connections, unlock), even though the subgraph that contains the phase error 
>> was not itself modified.
> 
> On which operating system do you experience this? I have noticed such 
> behavior  on OSX using the new audio-osx backend, but not using the portaudio 
> backend or on linux.

My audio chain does not use a GR audio_sink of any description — it exits the 
flowgraph through a single message_sink after vectorizing the channels.

The other two misbehaviors don't involve audio, or any sources or sinks. 
Furthermore, they can both be described as a subgraph (in one case, a concrete 
hier block) which has a single input and a single output, but two paths 
_within_ that subgraph which split and rejoin, and those two paths become out 
of sync with each other.

-- 
Kevin Reid                                  <http://switchb.org/kpreid/>