From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Revell Subject: Re: Couple of questions Date: Fri, 17 Mar 2006 18:58:10 -0500 Message-ID: <1142639891.25258.134.camel@mindpipe> References: <1142467271.9298.7.camel@localhost.localdomain> <1142552045.9236.9.camel@localhost.localdomain> <1142554597.9395.25.camel@mindpipe> <1142627252.9449.9.camel@localhost.localdomain> <1142638164.9449.16.camel@localhost.localdomain> <1142639182.25258.126.camel@mindpipe> <1142639470.9449.24.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from viper.oldcity.dca.net (viper.oldcity.dca.net [216.158.38.4]) by alsa.jcu.cz (ALSA's E-mail Delivery System) with SMTP id 1AD161BB for ; Sat, 18 Mar 2006 00:58:12 +0100 (MET) In-Reply-To: <1142639470.9449.24.camel@localhost.localdomain> Sender: alsa-devel-admin@lists.sourceforge.net Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Adrian McMenamin Cc: Takashi Iwai , alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org On Fri, 2006-03-17 at 23:51 +0000, Adrian McMenamin wrote: > On Fri, 2006-03-17 at 18:46 -0500, Lee Revell wrote: > > On Fri, 2006-03-17 at 23:29 +0000, Adrian McMenamin wrote: > > > > > > So, just to be clear. When I am transferring a "period" I should > > > actually stream half a period's worth of bytes into the channel > > > playing > > > the left and half a period into the right - and can advance each dma > > > transfer through the buffer by half a period length on both the left > > > and > > > the right side of the buffer > > > > No, one period. > > > > > How does that work? That would imply that there were half as many > periods in the DMA buffer as specified here... > > static snd_pcm_hardware_t snd_pcm_aica_playback_hw = { > > .info = (SNDRV_PCM_INFO_NONINTERLEAVED), > .formats = > (SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_LE | > SNDRV_PCM_FMTBIT_IMA_ADPCM), > .rates = SNDRV_PCM_RATE_8000_48000, > .rate_min = 8000, > .rate_max = 48000, > .channels_min = 2, > .channels_max = 2, > .buffer_bytes_max = AICA_BUFFER_SIZE, > .period_bytes_min = AICA_PERIOD_SIZE, > .period_bytes_max = AICA_PERIOD_SIZE, > .periods_min = AICA_PERIOD_NUMBER, > .periods_max = AICA_PERIOD_NUMBER, > }; > > > As the buffer and period (in bytes) size is constant. > > That's why the maximum buffer and period is in bytes not frames. Stereo has twice as many bytes per frame than mono. Lee ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642