[pulseaudio-discuss] alsa pulse bugs

[Colin Guthrie]

Colin Guthrie wrote:
> tom at dbservice.com wrote:
>>> Re the snd_pcm_delay() including network latency (#3945), this clearly
>>> makes sense for network streams. Does you proposed fix include this
>>> delay (albeit with the improvement that it also will drop to 0 if there
>>> are no samples queued)?
>> snd_pcm_delay() should not include any network latency. The API is  
>> defined as 'read pointer - write pointer', and applications expect  
>> that. Or at least they expect that when all samples are played that  
>> the delay drops to zero.
> 
> With the caveat of very limited technical knowledge, I can agree on the 
> latter point (drop to 0 when all samples are played), but if it was 
> implemented sans net-delay in pulse would this not cause e.g. a-v sync 
> issues when playing via alsa to a networked PA server? If so then this 
> fix would introduce another bug.

Actually just having a very quick glance at the Alsa API docs, it 
doesn't mention that this value should be 0 if there are no samples to play:

http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m.html#ga0d9e14a4be65209eb549e48a9f07302

Closest it says is: "It's positive and less than buffer size in normal 
situation".

So perhaps this is an invalid assumption at the wine side?

Is there perhaps a more appropriate API call they can use to do whatever 
test they are doing?

Col