сб, 4 мая 2019 г. в 20:25, Georg Chini <georg@xxxxxxxx>: > > On 04.05.19 16:42, Alexander E. Patrakov wrote: > > сб, 4 мая 2019 г. в 16:17, Georg Chini <georg@xxxxxxxx>: > >> Here is the new version of the header file, based on your feedback. > >> The main changes are: > >> > >> - The create_filter() function now receives the channel maps for input > >> and output. > >> - The create_filter() function receives a kill_filter() function and a > >> module pointer > >> which makes it possible for the filter to initiate unloading of the > >> module if it > >> detects that it is no longer applicable. > >> - An output_changed() function was added which communicates current sink > >> and port name to the filter, so that it can detect if the output has > >> changed. > >> > >> Also I did a bit of cleanup and added a few more comments. Hope it looks > >> better now. > > It definitely looks better. > > > > I am still confused about disable_rewind and max_latency. Let's > > suppose that someone wants to implement a rewindable filter. In this > > case, they need to keep history, because PulseAudio can ask the filter > > to rewind some samples. And, as it is not allowed to say "no", they > > must keep enough history to satisfy any possible rewind request. But > > some upper bound must exist. Do I understand correctly that > > max_latency serves as such upper bound? > > > > Regarding the non-rewindable filters, we do need to limit the latency, > > but I believe it is wrong for each individual filter to specify its > > own value for such limit. It should be a global policy (the same value > > for all non-rewindable sinks), and I don't see any reason for the > > filter to be able to influence it. > > > > Therefore, I believe these two fields can be replaced by one, > > max_rewind, which is the size of history, in samples, that the filter > > is willing to keep. Zero means a non-rewindable filter. > > > That sounds like a good suggestion. I would however think > that it is better if 0 means that the filter will rewind as far as > PA wants it to. There may be filters that are stateless (like the > trivial amplifier example). We could use -1 to disable rewinding. OK. > That would also mean to limit the latency to whatever the filter > can rewind, correct? I would use the maximum of max_rewind > and the default latency for non-rewindable filters as the > max_latency value then, because I don't think it makes sense > to set the maximum latency even smaller than for non-rewindable > filters. Makes sense. > What do you think is reasonable for non-rewindable filters? > 50 ms? There were different opinions on that matter. 50 ms is indeed in a range that I would agree to. -- Alexander E. Patrakov _______________________________________________ pulseaudio-discuss mailing list pulseaudio-discuss@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
