Always fully fill PulseAudio's requested buffer. Allow larger initial requests.

media/audio/pulse/pulse_output.cc

Index: media/audio/pulse/pulse_output.cc
diff --git a/media/audio/pulse/pulse_output.cc b/media/audio/pulse/pulse_output.cc
index 7cf66cb10c801ba9f7de12c9aae90d1e7e06dc40..2536b67fec131832946092b52a71dbda415b2958 100644
--- a/media/audio/pulse/pulse_output.cc
+++ b/media/audio/pulse/pulse_output.cc
@@ -157,8 +157,8 @@ bool PulseAudioOutputStream::Open() {
   pa_buffer_attr pa_buffer_attributes;
   pa_buffer_attributes.maxlength = params_.GetBytesPerBuffer();
   pa_buffer_attributes.minreq = params_.GetBytesPerBuffer();
-  pa_buffer_attributes.prebuf = params_.GetBytesPerBuffer();
-  pa_buffer_attributes.tlength = params_.GetBytesPerBuffer();
+  pa_buffer_attributes.prebuf = static_cast<uint32_t>(-1);
+  pa_buffer_attributes.tlength = static_cast<uint32_t>(-1);
   pa_buffer_attributes.fragsize = static_cast<uint32_t>(-1);
 
   // Connect playback stream.
@@ -238,43 +238,33 @@ void PulseAudioOutputStream::Close() {
 }
 
 void PulseAudioOutputStream::FulfillWriteRequest(size_t requested_bytes) {
-  CHECK_EQ(requested_bytes, static_cast<size_t>(params_.GetBytesPerBuffer()));
-
-  int frames_filled = 0;
-  if (source_callback_) {
-    uint32 hardware_delay = pulse::GetHardwareLatencyInBytes(
-        pa_stream_, params_.sample_rate(),
-        params_.GetBytesPerFrame());
-    frames_filled = source_callback_->OnMoreData(
-        audio_bus_.get(), AudioBuffersState(0, hardware_delay));
-  }
-
-  // Zero any unfilled data so it plays back as silence.
-  if (frames_filled < audio_bus_->frames()) {
-    audio_bus_->ZeroFramesPartial(
-        frames_filled, audio_bus_->frames() - frames_filled);
-  }
-
-  // PulseAudio won't always be able to provide a buffer large enough, so we may
-  // need to request multiple buffers and fill them individually.
-  int current_frame = 0;
-  size_t bytes_remaining = requested_bytes;
+  int bytes_remaining = requested_bytes;
   while (bytes_remaining > 0) {
     void* buffer = NULL;
-    size_t bytes_to_fill = bytes_remaining;
+    size_t bytes_to_fill = params_.GetBytesPerBuffer();
     CHECK_GE(pa_stream_begin_write(pa_stream_, &buffer, &bytes_to_fill), 0);
+    CHECK_EQ(bytes_to_fill, static_cast<size_t>(params_.GetBytesPerBuffer()));
+
+    int frames_filled = 0;
+    if (source_callback_) {
+      uint32 hardware_delay = pulse::GetHardwareLatencyInBytes(
+          pa_stream_, params_.sample_rate(),
+          params_.GetBytesPerFrame());
+      source_callback_->WaitTillDataReady();
+      frames_filled = source_callback_->OnMoreData(
+          audio_bus_.get(), AudioBuffersState(0, hardware_delay));
+    }
 
-    // In case PulseAudio gives us a bigger buffer than we want, cap our size.
-    bytes_to_fill = std::min(
-        std::min(bytes_remaining, bytes_to_fill),
-        static_cast<size_t>(params_.GetBytesPerBuffer()));
-
-    int frames_to_fill = bytes_to_fill / params_.GetBytesPerFrame();;
+    // Zero any unfilled data so it plays back as silence.
+    if (frames_filled < audio_bus_->frames()) {
+      audio_bus_->ZeroFramesPartial(
+          frames_filled, audio_bus_->frames() - frames_filled);
+    }
 
     // Note: If this ever changes to output raw float the data must be clipped
     // and sanitized since it may come from an untrusted source such as NaCl.
-    audio_bus_->ToInterleavedPartial(
-        current_frame, frames_to_fill, params_.bits_per_sample() / 8, buffer);
+    audio_bus_->ToInterleaved(
+        audio_bus_->frames(), params_.bits_per_sample() / 8, buffer);
     media::AdjustVolume(buffer, bytes_to_fill, params_.channels(),
                         params_.bits_per_sample() / 8, volume_);
 
@@ -286,7 +276,6 @@ void PulseAudioOutputStream::FulfillWriteRequest(size_t requested_bytes) {
     }
 
     bytes_remaining -= bytes_to_fill;
-    current_frame = frames_to_fill;
   }
 }