Cleanup OPUS decoder. Remove extraneous transforms and copies.

media/filters/audio_renderer_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/filters/audio_renderer_impl.h"
 
 #include <math.h>
 
 #include <algorithm>
 
@@ skipping 384 matching lines @@
     received_end_of_stream_ = true;
 
     // Transition to kPlaying if we are currently handling an underflow since
     // no more data will be arriving.
     if (state_ == kUnderflow || state_ == kRebuffering)
       ChangeState_Locked(kPlaying);
   } else {
     if (state_ == kPrerolling && IsBeforePrerollTime(buffer))
       return true;
 
-    if (state_ != kUninitialized && state_ != kStopped)
+    if (state_ != kUninitialized && state_ != kStopped) {
+      if (state_ == kPrerolling) {

[acolwell GONE FROM CHROMIUM, 2013/12/12 23:46:19]

nit: move this into the kPrerolling block above?

if (state_ == kPrerolling) {
  if (IsBeforePrerollTime(buffer))
    return true;

  ....
}

[DaleCurtis, 2013/12/13 03:19:11]

Done.

+        // Trim off any additional time before the preroll timestamp.
+        const base::TimeDelta trim_time =
+            preroll_timestamp_ - buffer->timestamp();
+        if (trim_time > base::TimeDelta()) {
+          buffer->TrimStart(buffer->frame_count() *
+                            (static_cast<double>(trim_time.InMicroseconds()) /
+                             buffer->duration().InMicroseconds()));
+        }
+      }
       algorithm_->EnqueueBuffer(buffer);
+    }
   }
 
   switch (state_) {
     case kUninitialized:
     case kFlushing:
       NOTREACHED();
       return false;
 
     case kPaused:
       DCHECK(!pending_read_);
@@ skipping 265 matching lines @@
   }
 }
 
 void AudioRendererImpl::ChangeState_Locked(State new_state) {
   DVLOG(1) << __FUNCTION__ << " : " << state_ << " -> " << new_state;
   lock_.AssertAcquired();
   state_ = new_state;
 }
 
 }  // namespace media