[vlc-devel] [PATCH] aout: play the silence buffer on most modules

[Thomas Guillem]

On Thu, Aug 15, 2019, at 16:44, Rémi Denis-Courmont wrote:
> Le torstaina 15. elokuuta 2019, 14.01.46 EEST Thomas Guillem a écrit :
> > Add a new capability: aout->module_info.can_play_at_date, only set by Pulse
> > (for now) since it is the only module that can handle a play_date !=
> > system_now.
> 
> PulseAudio cannot do anything that ALSA cannot do. The PulseAudio plugin uses 
> a deferred start timer instead of the core-assisted zero padding because it 
> *cannot* estimate the latency early enough. Any other plugin can do the same 
> with a timer; it's just silly to add that extra intricacy where unnecessary.
> 
> I cannot make any sense out of this description.
> 
> > This capability is checked by the aout core in order to tell if it should
> > first play a silence buffer (that has the same length than the jitter
> > delay).
> 
> I'm pretty sure it used to be so that the silence is played only if the module 
> returns a timing before the first buffer. There is no need to add a flag here.
> 
> > Before this commit, I assumed that a module could need a silence buffer only
> > if it returned a valid delay before the first play.
> 
> That assumption is correct.
> 
> > This assumption is now false
> 
> No. It cannot be false by design. Modules which, like PulseAudio, cannot meet 
> the requirement just have to handle the initial synchronization manually.
> 
> The core cannot do magic.

OK, cf. my new set that:
 - Add more documentation into vlc_aout.h
 - Implement start-deferred with coreaudio

> 
> -- 
> レミ・デニ-クールモン
> http://www.remlab.net/
> 
> 
> 
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