Fix incorrect opus seek preroll and flaky pre-skip removal.

media/filters/ffmpeg_audio_decoder.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/ffmpeg_audio_decoder.h"
 
 #include "base/callback_helpers.h"
 #include "base/single_thread_task_runner.h"
 #include "media/base/audio_buffer.h"
 #include "media/base/audio_bus.h"
@@ skipping 118 matching lines @@
     const scoped_refptr<MediaLog>& media_log)
     : task_runner_(task_runner),
       state_(kUninitialized),
       av_sample_format_(0),
       media_log_(media_log) {
 }
 
 FFmpegAudioDecoder::~FFmpegAudioDecoder() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
-  if (state_ != kUninitialized) {
+  if (state_ != kUninitialized)
     ReleaseFFmpegResources();
-    ResetTimestampState();
-  }
 }
 
 std::string FFmpegAudioDecoder::GetDisplayName() const {
   return "FFmpegAudioDecoder";
 }
 
 void FFmpegAudioDecoder::Initialize(const AudioDecoderConfig& config,
                                     const InitCB& init_cb,
                                     const OutputCB& output_cb) {
   DCHECK(task_runner_->BelongsToCurrentThread());
@@ skipping 211 matching lines @@
   if (!codec || avcodec_open2(codec_context_.get(), codec, NULL) < 0) {
     DLOG(ERROR) << "Could not initialize audio decoder: "
                 << codec_context_->codec_id;
     ReleaseFFmpegResources();
     state_ = kUninitialized;
     return false;
   }
 
   // Success!
   av_frame_.reset(av_frame_alloc());
-  discard_helper_.reset(new AudioDiscardHelper(config_.samples_per_second(),
-                                               config_.codec_delay()));
   av_sample_format_ = codec_context_->sample_fmt;
 
   if (codec_context_->channels !=
       ChannelLayoutToChannelCount(config_.channel_layout())) {
     DLOG(ERROR) << "Audio configuration specified "
                 << ChannelLayoutToChannelCount(config_.channel_layout())
                 << " channels, but FFmpeg thinks the file contains "
                 << codec_context_->channels << " channels";
     ReleaseFFmpegResources();
     state_ = kUninitialized;
     return false;
   }
 
   ResetTimestampState();
   return true;
 }
 
 void FFmpegAudioDecoder::ResetTimestampState() {
+  discard_helper_.reset(new AudioDiscardHelper(config_.samples_per_second(),
+                                               config_.codec_delay()));
   discard_helper_->Reset(config_.codec_delay());
 }
 
 }  // namespace media