* Re: [linux-audio-dev] muse and /dev/rtc [not found] ` <20041122175312.GA20957@bth05w.ABSp.alcatel.be> @ 2004-11-22 18:21 ` Lee Revell 2004-11-22 18:54 ` Takashi Iwai 2004-11-23 0:09 ` Fons Adriaensen 0 siblings, 2 replies; 4+ messages in thread From: Lee Revell @ 2004-11-22 18:21 UTC (permalink / raw) To: The Linux Audio Developers' Mailing List; +Cc: alsa-devel (added alsa-devel to cc) On Mon, 2004-11-22 at 18:53 +0100, Alfons Adriaensen wrote: > Which leads to the following question I've been asking myself for some time: > > the ALSA sequencer API seems to allow *timestamped* events - you put such > an event in a queue and it will appear at the other end at the right moment. > If this is true, and if ALSA has an high precision timer available to > implement it, why should apps like MusE bother to do the fine timing > themselves ? Yes, my thoughts exactly. You don't even have to use the ALSA sequencer API, you can use the ALSA timer API directly. You get multiple timer sources (system, RTC, sound card). It should also be more portable. For example if your sound card's timer is supported by your ALSA driver like emu10k1 and ymfpci then I think you can use this timer to give better sync with the hardware. ALSA devs, is this correct? Lee ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Re: [linux-audio-dev] muse and /dev/rtc 2004-11-22 18:21 ` [linux-audio-dev] muse and /dev/rtc Lee Revell @ 2004-11-22 18:54 ` Takashi Iwai 2004-11-23 0:32 ` Lee Revell 2004-11-23 0:09 ` Fons Adriaensen 1 sibling, 1 reply; 4+ messages in thread From: Takashi Iwai @ 2004-11-22 18:54 UTC (permalink / raw) To: Lee Revell; +Cc: The Linux Audio Developers' Mailing List, alsa-devel At Mon, 22 Nov 2004 13:21:07 -0500, Lee Revell wrote: > > (added alsa-devel to cc) > > On Mon, 2004-11-22 at 18:53 +0100, Alfons Adriaensen wrote: > > Which leads to the following question I've been asking myself for some time: > > > > the ALSA sequencer API seems to allow *timestamped* events - you put such > > an event in a queue and it will appear at the other end at the right moment. > > If this is true, and if ALSA has an high precision timer available to > > implement it, why should apps like MusE bother to do the fine timing > > themselves ? > > Yes, my thoughts exactly. You don't even have to use the ALSA sequencer > API, you can use the ALSA timer API directly. You get multiple timer > sources (system, RTC, sound card). It should also be more portable. > For example if your sound card's timer is supported by your ALSA driver > like emu10k1 and ymfpci then I think you can use this timer to give > better sync with the hardware. > > ALSA devs, is this correct? Yes, I agree that ALSA timer API would be useful for such a case. The app can reject to run or do some workaround if the queried timer resolution is worse than requirements. Well, my guess for the next reaction is "the lack of documentation" ;) Takashi ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Re: [linux-audio-dev] muse and /dev/rtc 2004-11-22 18:54 ` Takashi Iwai @ 2004-11-23 0:32 ` Lee Revell 0 siblings, 0 replies; 4+ messages in thread From: Lee Revell @ 2004-11-23 0:32 UTC (permalink / raw) To: Takashi Iwai; +Cc: The Linux Audio Developers' Mailing List, alsa-devel On Mon, 2004-11-22 at 19:54 +0100, Takashi Iwai wrote: > Yes, I agree that ALSA timer API would be useful for such a case. The > app can reject to run or do some workaround if the queried timer > resolution is worse than requirements. > > Well, my guess for the next reaction is "the lack of documentation" ;) I think the only issue is that adding timer support to a driver is not documented. I did not even know ALSA had a timer API until it was pointed out to me on the list, as the driver guide was my main reference. Adding a chapter to the guide would ensure that new drivers get timer support. Lee ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [linux-audio-dev] muse and /dev/rtc 2004-11-22 18:21 ` [linux-audio-dev] muse and /dev/rtc Lee Revell 2004-11-22 18:54 ` Takashi Iwai @ 2004-11-23 0:09 ` Fons Adriaensen 1 sibling, 0 replies; 4+ messages in thread From: Fons Adriaensen @ 2004-11-23 0:09 UTC (permalink / raw) To: The Linux Audio Developers' Mailing List; +Cc: alsa-devel On Mon, Nov 22, 2004 at 01:21:07PM -0500, Lee Revell wrote: > Yes, my thoughts exactly. You don't even have to use the ALSA sequencer > API, you can use the ALSA timer API directly. You get multiple timer > sources (system, RTC, sound card). It should also be more portable. Yes, but using the sequencer's timing should require less process swaps. -- FA ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2004-11-23 0:32 UTC | newest]
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2004-11-22 18:21 ` [linux-audio-dev] muse and /dev/rtc Lee Revell
2004-11-22 18:54 ` Takashi Iwai
2004-11-23 0:32 ` Lee Revell
2004-11-23 0:09 ` Fons Adriaensen
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