[Chromecast] Fix issue where new playback rate was never used

chromecast/media/cma/backend/alsa/audio_decoder_alsa.cc

 // Copyright 2015 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 "chromecast/media/cma/backend/alsa/audio_decoder_alsa.h"
 
 #include <time.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 135 matching lines @@
   return true;
 }
 
 bool AudioDecoderAlsa::SetPlaybackRate(float rate) {
   if (std::abs(rate - 1.0) < kPlaybackRateEpsilon) {
     // AudioRendererAlgorithm treats values close to 1 as exactly 1.
     rate = 1.0f;
   }
   LOG(INFO) << "SetPlaybackRate to " << rate;
 
-  while (!rate_shifter_info_.empty() &&
-         rate_shifter_info_.back().input_frames == 0) {
-    rate_shifter_info_.pop_back();
+  // Remove info for rates that have no pending output left.
+  while (!rate_shifter_info_.empty()) {
+    RateShifterInfo* rate_info = &rate_shifter_info_.back();
+    int64_t possible_output_frames = rate_info->input_frames / rate_info->rate;
+    DCHECK_GE(possible_output_frames, rate_info->output_frames);
+    if (rate_info->output_frames == possible_output_frames) {
+      rate_shifter_info_.pop_back();
+    } else {
+      break;
+    }
   }
+
   rate_shifter_info_.push_back(RateShifterInfo(rate));
   return true;
 }
 
 AudioDecoderAlsa::BufferStatus AudioDecoderAlsa::PushBuffer(
     CastDecoderBuffer* buffer) {
   TRACE_FUNCTION_ENTRY0();
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(buffer);
   DCHECK(!got_eos_);
@@ skipping 174 matching lines @@
   if (decoded->end_of_stream()) {
     got_eos_ = true;
   } else {
     int input_frames = decoded->data_size() / (kNumChannels * sizeof(float));
 
     DCHECK(!rate_shifter_info_.empty());
     RateShifterInfo* rate_info = &rate_shifter_info_.front();
     // Bypass rate shifter if the rate is 1.0, and there are no frames queued
     // in the rate shifter.
     if (rate_info->rate == 1.0 && rate_shifter_->frames_buffered() == 0 &&
-        pending_output_frames_ == kNoPendingOutput) {
+        pending_output_frames_ == kNoPendingOutput &&
+        rate_shifter_info_.size() == 1) {
       DCHECK_EQ(rate_info->output_frames, rate_info->input_frames);
       pending_output_frames_ = input_frames;
       if (got_eos_) {
         DCHECK(!pushed_eos_);
         pushed_eos_ = true;
       }
       mixer_input_->WritePcm(decoded);
       return;
     }
 
@@ skipping 91 matching lines @@
   scoped_refptr<DecoderBufferBase> output_buffer(new DecoderBufferAdapter(
       new ::media::DecoderBuffer(channel_data_size * kNumChannels)));
   for (int c = 0; c < kNumChannels; ++c) {
     memcpy(output_buffer->writable_data() + c * channel_data_size,
            rate_shifter_output_->channel(c), channel_data_size);
   }
   pending_output_frames_ = out_frames;
   mixer_input_->WritePcm(output_buffer);
 
   if (rate_shifter_info_.size() > 1 &&
-      possible_output_frames == rate_info->output_frames) {
+      rate_info->output_frames == possible_output_frames) {
     double remaining_input_frames =
         rate_info->input_frames - (rate_info->output_frames * rate_info->rate);
     rate_shifter_info_.pop_front();
 
     rate_info = &rate_shifter_info_.front();
     LOG(INFO) << "New playback rate in effect: " << rate_info->rate;
     rate_info->input_frames += remaining_input_frames;
     DCHECK_EQ(0, rate_info->output_frames);
 
     // If new playback rate is 1.0, clear out 'extra' data in the rate shifter.
@@ skipping 50 matching lines @@
   TRACE_FUNCTION_ENTRY0();
   DCHECK(task_runner_->BelongsToCurrentThread());
   if (error != MixerError::kInputIgnored)
     LOG(ERROR) << "Mixer error occurred.";
   mixer_error_ = true;
   delegate_->OnDecoderError();
 }
 
 }  // namespace media
 }  // namespace chromecast