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@@ -28,6 +28,18 @@ Set Client Name. |
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Use this Soundcard. |
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.TP |
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\fB\-v\fR |
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.br |
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Verbose, prints out resample coefficient and other parameters useful for debugging, every 500ms. |
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also reports soft xruns. |
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.TP |
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\fB\-i\fR |
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.br |
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Instrumentation. This logs the 4 important parameters of the samplerate control algorithm every 1ms. |
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You can pipe this into a file, and plot it. Should only be necessary, if it does not work as |
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expected, and we need to adjust some of the obscure parameters, to make it work. |
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Find me on irc.freenode.org #jack in order to set this up correctly. |
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\fB\-c \fI channels\fR |
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Set Number of channels. |
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@@ -36,37 +48,35 @@ Set Number of channels. |
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Set sample_rate. The program resamples as necessary. |
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So you can connect a 44k1 jackd to a soundcard only supporting |
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48k. |
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48k. (default is jack sample_rate) |
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.TP |
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\fB\-m \fI max_diff\fR |
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.br |
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The value when a soft xrun occurs. Basically the window, in which |
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the dma pointer may jitter. If you see "delay=" in the output of alsa_out |
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this is too small. |
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\fB\-p \fI period_size\fR |
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.br |
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Make sure target_delay is bigger than this. |
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Set the period size. It is not related to the jackd period_size. |
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Sometimes it affects the quality of the delay measurements. |
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Setting this lower than the jackd period_size will only work, if you |
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use a higher number of periods. |
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.TP |
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\fB\-t \fI target_delay\fR |
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\fB\-n \fI num_period\fR |
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The delay alsa_io should try to approach. Tune this to get lower latency. |
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Must be bigger than max_diff for alsa_out, and should be bigger than max_diff+jackd_period |
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for alsa_in. |
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Set number of periods. See note for period_size. |
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.TP |
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\fB\-f \fI catch_factor\fR |
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\fB\-m \fI max_diff\fR |
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.br |
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This value sets how fast the samplerate will change. |
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default is 1000. Try 10000 when you have good relation between |
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your clocksources. This will make resampling inaudible for example. |
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The value when a soft xrun occurs. Basically the window, in which |
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the dma pointer may jitter. I dont think its necessary to play with this anymore. |
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.TP |
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\fB\-p \fI period_size\fR |
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\fB\-t \fI target_delay\fR |
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Set the period size. It is not related to the jackd period_size. |
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Sometimes it affects the quality of the delay measurements. |
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Thats why its configurable. |
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The delay alsa_io should try to approach. Same as for max_diff. It will be setup based on -p and -n |
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which is generally sufficient. |
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.TP |
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\fB\-n \fI num_period\fR |
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\fB\-C \fI P Control Clamp\fR |
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Set number of periods. See note for period_size. |
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If you have a PCI card, then the default value (15) of this parameter is too high for -p64 -n2... Setting it to 5 should fix that. |
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Be aware that setting this parameter too low, lets the hf noise on the delay measurement come through onto the resamplerate, so this |
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might degrade the quality of the output. (but its a threshold value, and it has been chosen, to mask the noise of a USB card, |
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which has an amplitude which is 50 times higher than that of a PCI card, so 5 wont loose you any quality on a PCI card) |
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.SH AUTHOR |
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Torben Hohn |
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torben
17 years ago