[alsa-devel] [patch] dmix skipping first set of samples
There was a change in alsa-lib 1.0.16 which looks like it was designed to make dmix skip samples in the case of underruns, but it causes the first sample to be skipped since dmix->slave_hw_ptr == dmix->slave_appl_ptr. The following patch fixes this and fixes a small typo in the comment:
--- src/pcm/pcm_dmix.c.orig 2008-01-18 20:00:10.000000000 -0500 +++ src/pcm/pcm_dmix.c 2008-03-09 18:01:13.000000000 -0400 @@ -311,9 +311,9 @@ if (size >= pcm->boundary / 2) size = pcm->boundary - size;
- /* the slave_app_ptr can be far behing the slave_hw_ptr */ + /* the slave_app_ptr can be far behind the slave_hw_ptr */ /* reduce mixing and errors here - just skip not catched writes */ - if (dmix->slave_hw_ptr < dmix->slave_appl_ptr) + if (dmix->slave_hw_ptr <= dmix->slave_appl_ptr) slave_size = dmix->slave_appl_ptr - dmix->slave_hw_ptr; else slave_size = dmix->slave_appl_ptr + (dmix->slave_boundary - dmix->slave_hw_ptr);
Thanks, -- Mike Gorse / AIM:linvortex / http://mgorse.freeshell.org --
At Sun, 9 Mar 2008 18:20:47 -0400 (EDT), Mike Gorse wrote:
There was a change in alsa-lib 1.0.16 which looks like it was designed to make dmix skip samples in the case of underruns, but it causes the first sample to be skipped since dmix->slave_hw_ptr == dmix->slave_appl_ptr. The following patch fixes this and fixes a small typo in the comment:
A good catch! Applied to HG tree now.
Thanks.
Takashi
--- src/pcm/pcm_dmix.c.orig 2008-01-18 20:00:10.000000000 -0500 +++ src/pcm/pcm_dmix.c 2008-03-09 18:01:13.000000000 -0400 @@ -311,9 +311,9 @@ if (size >= pcm->boundary / 2) size = pcm->boundary - size;
- /* the slave_app_ptr can be far behing the slave_hw_ptr */
- /* the slave_app_ptr can be far behind the slave_hw_ptr */ /* reduce mixing and errors here - just skip not catched writes */
- if (dmix->slave_hw_ptr < dmix->slave_appl_ptr)
- if (dmix->slave_hw_ptr <= dmix->slave_appl_ptr) slave_size = dmix->slave_appl_ptr - dmix->slave_hw_ptr; else slave_size = dmix->slave_appl_ptr + (dmix->slave_boundary - dmix->slave_hw_ptr);
Thanks, -- Mike Gorse / AIM:linvortex / http://mgorse.freeshell.org -- _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
participants (2)
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Mike Gorse
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Takashi Iwai