It seems that snd_pcm_hw_params_set_* API does not work well any more in the latest ubuntu like 12.04. My tests show that it will freeze the pulseaudio for a while and get into underrun state. And it seems snd_pcm_set_params works better for the same purpose.

This patch also fixes the choppy audio issue for webrtc in ubuntu 12.04.

BUG=152232,153505
TEST=use pepper flash (./out/Debug/chrome -ppapi-flash-path=/your/path/libpepflashplayer.so)
open link http://www.youtube.com/watch?v=F7pYHN9iC9I&feature=youtu.be in two tabs, audio should be good.
uses apprtc.appspot.com to make a loopback call and verify the audio is good on ubuntu 12.04

Review URL: https://chromiumcodereview.appspot.com/11019010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@159680 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 66 deletions

diff --git a/media/audio/linux/alsa_wrapper.cc b/media/audio/linux/alsa_wrapper.cc
index 67331b4..c1ce359 100644
--- a/media/audio/linux/alsa_wrapper.cc
+++ b/media/audio/linux/alsa_wrapper.cc
@@ -71,76 +71,17 @@ const char* AlsaWrapper::PcmName(snd_pcm_t* handle) {
   return snd_pcm_name(handle);
 }
 
-int AlsaWrapper::ConfigureHwParams(snd_pcm_t* handle,
-                                   snd_pcm_hw_params_t* hw_params,
-                                   snd_pcm_format_t format,
-                                   snd_pcm_access_t access,
-                                   unsigned int channels,
-                                   unsigned int rate,
-                                   int soft_resample,
-                                   unsigned int latency) {
-  int err = 0;
-  if ((err = snd_pcm_hw_params_any(handle, hw_params)) < 0)
-    return err;
-
-  if ((err = snd_pcm_hw_params_set_rate_resample(handle, hw_params,
-                                                 soft_resample)) < 0) {
-    return err;
-  }
-
-  if ((err = snd_pcm_hw_params_set_format(handle, hw_params, format)) < 0)
-    return err;
-
-  int dir = 0;
-  unsigned new_rate = rate;
-  if ((err = snd_pcm_hw_params_set_rate_near(handle, hw_params,
-                                             &new_rate, &dir)) < 0) {
-    return err;
-  }
-
-  if ((err = snd_pcm_hw_params_set_access(handle, hw_params, access)) < 0)
-    return err;
-
-  if ((err = snd_pcm_hw_params_set_channels(handle, hw_params, channels)) < 0)
-    return err;
-
-  unsigned buffer_time = latency;
-  if (buffer_time == 0) {
-    if ((err = snd_pcm_hw_params_get_buffer_time_max(hw_params,
-                                                      &buffer_time, 0)) < 0) {
-      return err;
-    }
-    if (buffer_time > 500000)
-      buffer_time = 500000;
-  }
-
-  unsigned period_time = buffer_time / 4;
-  if ((err = snd_pcm_hw_params_set_period_time_near(handle, hw_params,
-                                                    &period_time, 0)) < 0) {
-    return err;
-  }
-
-  err = snd_pcm_hw_params_set_buffer_time_near(handle, hw_params,
-                                                &buffer_time, 0);
-  return err;
-}
-
 int AlsaWrapper::PcmSetParams(snd_pcm_t* handle, snd_pcm_format_t format,
                               snd_pcm_access_t access, unsigned int channels,
                               unsigned int rate, int soft_resample,
                               unsigned int latency) {
-  int err = 0;
-  snd_pcm_hw_params_t* hw_params;
-  if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0)
-    return err;
-
-  if ((err = ConfigureHwParams(handle, hw_params, format, access, channels,
-                               rate, soft_resample, latency)) >= 0) {
-    err = snd_pcm_hw_params(handle, hw_params);
-  }
-
-  snd_pcm_hw_params_free(hw_params);
-  return err;
+  return snd_pcm_set_params(handle,
+                            format,
+                            access,
+                            channels,
+                            rate,
+                            soft_resample,
+                            latency);
 }
 
 int AlsaWrapper::PcmGetParams(snd_pcm_t* handle, snd_pcm_uframes_t* buffer_size,