To M56: Use ffmpeg for opus decoding, no need to maintain our decoder.

media/base/audio_discard_helper.cc

 // Copyright 2014 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/base/audio_discard_helper.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "media/base/audio_buffer.h"
 
 namespace media {
 
 static void WarnOnNonMonotonicTimestamps(base::TimeDelta last_timestamp,
                                          base::TimeDelta current_timestamp) {
   if (last_timestamp == kNoTimestamp || last_timestamp < current_timestamp)
     return;
 
   const base::TimeDelta diff = current_timestamp - last_timestamp;
   DLOG(WARNING) << "Input timestamps are not monotonically increasing! "
                 << " ts " << current_timestamp.InMicroseconds() << " us"
                 << " diff " << diff.InMicroseconds() << " us";
 }
 
-AudioDiscardHelper::AudioDiscardHelper(int sample_rate, size_t decoder_delay)
+AudioDiscardHelper::AudioDiscardHelper(int sample_rate,
+                                       size_t decoder_delay,
+                                       bool delayed_discard)
     : sample_rate_(sample_rate),
       decoder_delay_(decoder_delay),
       timestamp_helper_(sample_rate_),
       discard_frames_(0),
       last_input_timestamp_(kNoTimestamp),
-      delayed_discard_(false),
+      delayed_discard_(delayed_discard),
       delayed_end_discard_(0) {
   DCHECK_GT(sample_rate_, 0);
 }
 
 AudioDiscardHelper::~AudioDiscardHelper() {
 }
 
 size_t AudioDiscardHelper::TimeDeltaToFrames(base::TimeDelta duration) const {
   DCHECK(duration >= base::TimeDelta());
   return duration.InSecondsF() * sample_rate_ + 0.5;
 }
 
 void AudioDiscardHelper::Reset(size_t initial_discard) {
   discard_frames_ = initial_discard;
   last_input_timestamp_ = kNoTimestamp;
   timestamp_helper_.SetBaseTimestamp(kNoTimestamp);
-  delayed_discard_ = false;
   delayed_discard_padding_ = DecoderBuffer::DiscardPadding();
 }
 
 bool AudioDiscardHelper::ProcessBuffers(
     const scoped_refptr<DecoderBuffer>& encoded_buffer,
     const scoped_refptr<AudioBuffer>& decoded_buffer) {
   DCHECK(!encoded_buffer->end_of_stream());
   DCHECK(encoded_buffer->timestamp() != kNoTimestamp);
 
   // Issue a debug warning when we see non-monotonic timestamps.  Only a warning
   // to allow chained OGG playback.
   WarnOnNonMonotonicTimestamps(last_input_timestamp_,
                                encoded_buffer->timestamp());
   last_input_timestamp_ = encoded_buffer->timestamp();
 
   // If this is the first buffer seen, setup the timestamp helper.
-  const bool first_buffer = !initialized();
-  if (first_buffer) {
+  if (!initialized()) {
     // Clamp the base timestamp to zero.
     timestamp_helper_.SetBaseTimestamp(
         std::max(base::TimeDelta(), encoded_buffer->timestamp()));
   }
   DCHECK(initialized());
 
   if (!decoded_buffer.get()) {
     // If there's a one buffer delay for decoding, we need to save it so it can
     // be processed with the next decoder buffer.
-    if (first_buffer) {
-      delayed_discard_ = true;
+    if (delayed_discard_)
       delayed_discard_padding_ = encoded_buffer->discard_padding();
-    }
     return false;
   }
 
   const size_t original_frame_count = decoded_buffer->frame_count();
 
   // If there's a one buffer delay for decoding, pick up the last encoded
   // buffer's discard padding for processing with the current decoded buffer.
   DecoderBuffer::DiscardPadding current_discard_padding =
       encoded_buffer->discard_padding();
   if (delayed_discard_) {
@@ skipping 142 matching lines @@
   DVLOG(3) << __func__ << " ts: " << timestamp_helper_.GetTimestamp()
            << " frames: " << decoded_buffer->frame_count();
 
   // Assign timestamp to the buffer.
   decoded_buffer->set_timestamp(timestamp_helper_.GetTimestamp());
   timestamp_helper_.AddFrames(decoded_buffer->frame_count());
   return true;
 }
 
 }  // namespace media