All of lore.kernel.org
 help / color / mirror / Atom feed
From: James Courtier-Dutton <James@superbug.demon.co.uk>
To: alsa-devel <alsa-devel@lists.sourceforge.net>
Subject: emu10k1 capture period sizes?
Date: Fri, 26 Mar 2004 14:40:53 +0000	[thread overview]
Message-ID: <406440F5.2030101@superbug.demon.co.uk> (raw)

Extract from ./sound/pci/emu10k1/emupcm.c

static unsigned int capture_period_sizes[31] = {
         384,    448,    512,    640,
         384*2,  448*2,  512*2,  640*2,
         384*4,  448*4,  512*4,  640*4,
         384*8,  448*8,  512*8,  640*8,
         384*16, 448*16, 512*16, 640*16,
         384*32, 448*32, 512*32, 640*32,
         384*64, 448*64, 512*64, 640*64,
         384*128,448*128,512*128
};

This makes the minimum period size that I can record from the MIC to be 
384 frames.

I would like period sized to be 20ms (Used by the GSM codec) in length 
for a VoIP application I am working on. VoIP generally works with 8000Hz 
sample rate to match that on Telco ISDN/Digital trunk lines.

If the sample rate is 8000Hz, a period size of 384 frames makes for a 
48ms which would add too much latency to the conversation.

Ideally I would like to set the minimum period size to be 160 frames 
which is 20ms.

Is there any technical reason why I cannot just add 160 to the table above?

If it is ok, can someone please add it to the alsa-driver tree.

Cheers
James


-------------------------------------------------------
This SF.Net email is sponsored by: IBM Linux Tutorials
Free Linux tutorial presented by Daniel Robbins, President and CEO of
GenToo technologies. Learn everything from fundamentals to system
administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click

             reply	other threads:[~2004-03-26 14:40 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-03-26 14:40 James Courtier-Dutton [this message]
2004-03-26 14:58 ` emu10k1 capture period sizes? Jaroslav Kysela

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=406440F5.2030101@superbug.demon.co.uk \
    --to=james@superbug.demon.co.uk \
    --cc=alsa-devel@lists.sourceforge.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.