Re: [SlimDevices: Plugins] Squeezelite -a ::: - can anyone explain this option?
bpa wrote: > my basic understanding. > > PCM Audio is sent via ALSA interface to ALSA device driver. > > Audio samples are put into a ring buffer. > The ring buffer size is controlled by the buffer parameter. > The ring buffer is processed in terms of periods (i.e there x periods in > the whole buffer). > A period the number of frames per h/w interrupts (edit: corrected from > first post) > I don't know how samples are fitted into frames. > > The audio samples can either be copied into buffer using API Read/write > or the buffer can be memory mapped into calling process memory so no > additional copying of audio data. > > These are all hardware paramaters and so valid values are dependent on > the audio device. > > edit: > > Found an explanation of frames and periods. > > > https://www.alsa-project.org/main/index.php/FramesPeriods > > edit 2: > > Working link to writing-an-alsa-driver.pdf > https://www.ibr.cs.tu-bs.de/theses/kurtisi/NMP-EmbeddedClient/Abgabe/Quellen/writing-an-alsa-driver.pdf That's great and it makes a lot more sense now. Thanks very much! SB3 -> Quad 909 -> Quad Electrostatic speakers, Quad 405 -> TBI subwoofer 3 x SB3s + SB Radio LMS on Raspbian on a Pi4 Rotel RSP1068 surround processor, Quad 707 -> B surround rbl's Profile: http://forums.slimdevices.com/member.php?userid=4517 View this thread: http://forums.slimdevices.com/showthread.php?t=114868 ___ plugins mailing list plugins@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/plugins
Re: [SlimDevices: Plugins] Squeezelite -a ::: - can anyone explain this option?
my basic understanding. PCM Audio is sent via ALSA interface to ALSA device driver. Audio samples are put into a ring buffer. The ring buffer size is controlled by the buffer parameter. The ring buffer is processed in terms of periods (i.e there x periods in the whole buffer). There is one frame per period. I don't know how samples are fitted into frames. The audio samples can either be copied into buffer using API Read/write or the buffer can be memory mapped into calling process memory so no additional copying of audio data. These are all hardware paramaters and so valid values are dependent on the audio device. bpa's Profile: http://forums.slimdevices.com/member.php?userid=1806 View this thread: http://forums.slimdevices.com/showthread.php?t=114868 ___ plugins mailing list plugins@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/plugins
Re: [SlimDevices: Plugins] Squeezelite -a ::: - can anyone explain this option?
There is a bit more explanation on Ralphy's github page "For ALSA, the format is used where is the buffer time in milliseconds (values less than 500) or size in bytes (default 40ms); is the period count (values less than 50) or size in bytes (default 4 periods); is the sample format (possible values: 16, 24, 24_3 or 32); is whether to use mmap (possible values: 0 or 1). open ALSA output device twice. (possible values: 0 or 1)." https://ralph-irving.github.io/squeezelite.html ALSA mmap https://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___direct.html Paul Webster http://dabdig.blogspot.com author of \"now playing\" plugins covering radio france (fip etc), planetradio (bauer - kiss, absolute, scala, jazzfm etc), kcrw, supla finland, abc australia, cbc/radio-canada and rte ireland Paul Webster's Profile: http://forums.slimdevices.com/member.php?userid=105 View this thread: http://forums.slimdevices.com/showthread.php?t=114868 ___ plugins mailing list plugins@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/plugins
[SlimDevices: Plugins] Squeezelite -a ::: - can anyone explain this option?
Hi - running SqueezeLite and LMS 8.1.2 (latest versions) on my Pi4 I found there was serious rebuffering on my Pi and SB3s earlier this year when playing FLACs unless I specified "-a :::0". More recently I noticed some background/popping noise on the Pi's headphone jack unless I specified "-a 120:4::0". The wiki says the following about the -a option: "-a ::: Specify ALSA params to open output device, b = buffer time in ms or size in bytes, p = period count or size in bytes, f sample format (16|24|24_3|32), m = use mmap (0|1) https://www.max2play.com/en/wiki/command-line-options-for-squeezelite/ Frankly I have no idea what this means! - which buffer is affected and how do I know if the specified numbers are in ms or bytes? - what is "period count" - which sample format? Surely the FLAC is what it is? - what is mmap? Any insights, or just a reference page, would be much appreciated so I can understand more as to what is going on. R SB3 -> Quad 909 -> Quad Electrostatic speakers, Quad 405 -> TBI subwoofer 3 x SB3s + SB Radio LMS on Raspbian on a Pi4 Rotel RSP1068 surround processor, Quad 707 -> B surround rbl's Profile: http://forums.slimdevices.com/member.php?userid=4517 View this thread: http://forums.slimdevices.com/showthread.php?t=114868 ___ plugins mailing list plugins@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/plugins
