f9dff1f9fa
It may be the case that you may hear some unwanted noise while playing back with 24/32 bit. This is a problem in the USB system. Explanation from Hans Petter Selasky: ---snip--- The current USB sound driver only uses one isochronous buffer, that is restarted when it is completed. This will lead to a short period of time, +1ms, where no sound data is sent to the external USB device. Depending on the load of your computer, this can be as much as 50ms. So the USB sound driver must use 2 isochronous transfers. At the beginning one will queue both. Then these are restarted on completion. This will result in a constant-rate data stream to the external sound device, a minimum sound buffer equal to the size of the isochronous buffer, and possibly the sound will reach your ears with less delay. Little delay is a result of constant data rate. Currently only my USB driver will support that. If one tries that with the USB driver in *BSD, then it will crash at the first moment one gets a buffer underrun. ---snip--- Submitted by: Kazuhito HONDA <kazuhito@ph.noda.tus.ac.jp> Mono-recording still not tested by: julian
54 lines
2.5 KiB
C
54 lines
2.5 KiB
C
/* $FreeBSD$ */
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/*-
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* Copyright (c) 2000-2002 Hiroyuki Aizu <aizu@navi.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if 0
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#define NO_RECORDING /* XXX: some routines missing from uaudio.c */
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#endif
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/* Defined in uaudio.c, used in uaudio_pcm,c */
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void uaudio_chan_set_param_pcm_dma_buff(device_t dev, u_char *start,
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u_char *end, struct pcm_channel *pc, int dir);
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int uaudio_trigger_output(device_t dev);
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int uaudio_halt_out_dma(device_t dev);
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#ifndef NO_RECORDING
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int uaudio_trigger_input(device_t dev);
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int uaudio_halt_in_dma(device_t dev);
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#endif
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void uaudio_chan_set_param(device_t, u_char *, u_char *);
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void uaudio_chan_set_param_blocksize(device_t dev, u_int32_t blocksize, int dir);
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int uaudio_chan_set_param_speed(device_t dev, u_int32_t speed, int reqdir);
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void uaudio_chan_set_param_format(device_t dev, u_int32_t format,int dir);
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int uaudio_chan_getptr(device_t dev, int);
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void uaudio_mixer_set(device_t dev, unsigned type, unsigned left,
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unsigned right);
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u_int32_t uaudio_mixer_setrecsrc(device_t dev, u_int32_t src);
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u_int32_t uaudio_query_mix_info(device_t dev);
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u_int32_t uaudio_query_recsrc_info(device_t dev);
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unsigned uaudio_query_formats(device_t dev, int dir, unsigned maxfmt, struct pcmchan_caps *fmt);
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void uaudio_sndstat_register(device_t dev);
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