On 02/15/2018 12:43 PM, Georg Chini wrote: > On 15.02.2018 10:31, Raman Shishniou wrote: >> On 02/15/2018 10:20 AM, Georg Chini wrote: >>> On 14.02.2018 22:51, Raman Shishniou wrote: >>>> On 02/14/2018 07:20 PM, Georg Chini wrote: >>>>> On 14.02.2018 15:25, Raman Shyshniou wrote: >>>>>> This patch adds a underrun_protection argument to >>>>>> control underrun protection algorithm. Disabling >>>>>> protection will keep loopback latency regardless >>>>>> of underruns. >>>>> Again I do not understand the motivation of the patch. >>>>> In what situations are you seeing so many underruns and >>>>> still want to keep the original configured latency value? >>>>> Audio will be very bad in that case. >>>>> >>>> All situations where where latency is more important than data integrity. >>>> Voice over IP (telephony) for example, receiving audio data using network >>>> by UDP/RTP. Any data loss leads to underruns in loopback module. >>> This is not correct. It will only lead to underruns, if module-loopback runs >>> out of data. So if you buffer enough data, missing packets in the voice >>> stream would just appear to be small sample rate variations from the >>> perspective of the loopback module. Because the loopback module >>> does some adaptive re-sampling, these variations are no problem. >>> >>> Maybe this happens for you because module-pipe-source has no buffer >>> at all and simply passes the values through whenever data arrives. >>> With missing data packets, this can surely lead to underruns on the >>> source side which are passed on to the loopback module. >>> Perhaps you should implement some buffering in pipe-source? >>> >>> I don't see the point of your change. If you are seeing massive underruns, >>> audio quality will be really bad and just sticking to the configured latency >>> will not improve the situation. For me, the permanent occurrence of >>> underruns shows that there is something wrong with your setup in the first >>> place. The better idea is to correct the audio chain, so that no (or only very >>> few) underruns happen. >> I Agree. For live streaming or internet radio I can buffer more data up to >> several seconds (or just use tcp). But not for telephony, where 10-20 >> underruns per hour is acceptable, but latency more than 50-100ms is not. >> Loopback module increases latency permanently. There is no way to decrease >> it without unload and load again. > > How about a max_latency_msec argument in the sense that the logic > will not be completely disabled, but module-loopback will not try to > increase the latency above max_latency_msec (if specified) even if > underruns occur? > I can see that, it makes sense to me. I'll make the patch.
