Don't double correct for discarded codec delay frames.

media/filters/audio_file_reader.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_file_reader.h"
 
 #include <cmath>
 
 #include "base/logging.h"
 #include "base/time/time.h"
@@ skipping 108 matching lines @@
 
   // Holds decoded audio.
   scoped_ptr<AVFrame, ScopedPtrAVFreeFrame> av_frame(av_frame_alloc());
 
   // Read until we hit EOF or we've read the requested number of frames.
   AVPacket packet;
   int current_frame = 0;
   bool continue_decoding = true;
 
   while (current_frame < audio_bus->frames() && continue_decoding &&
-         av_read_frame(glue_->format_context(), &packet) >= 0 &&
-         av_dup_packet(&packet) >= 0) {
-    // Skip packets from other streams.
-    if (packet.stream_index != stream_index_) {
-      av_free_packet(&packet);
-      continue;
-    }
-
+         ReadPacket(&packet)) {
     // Make a shallow copy of packet so we can slide packet.data as frames are
     // decoded from the packet; otherwise av_free_packet() will corrupt memory.
     AVPacket packet_temp = packet;
     do {
       avcodec_get_frame_defaults(av_frame.get());
       int frame_decoded = 0;
       int result = avcodec_decode_audio4(
           codec_context_, av_frame.get(), &frame_decoded, &packet_temp);
 
       if (result < 0) {
@@ skipping 91 matching lines @@
   // One microsecond is much less than the time of a single sample-frame
   // at any real-world sample-rate.
   return ConvertFromTimeBase(av_time_base,
                              glue_->format_context()->duration + 1);
 }
 
 int AudioFileReader::GetNumberOfFrames() const {
   return static_cast<int>(ceil(GetDuration().InSecondsF() * sample_rate()));
 }
 
+bool AudioFileReader::ReadPacketForTesting(AVPacket* output_packet) {
+  return ReadPacket(output_packet);
+}
+
+bool AudioFileReader::ReadPacket(AVPacket* output_packet) {
+  while (av_read_frame(glue_->format_context(), output_packet) >= 0 &&
+         av_dup_packet(output_packet) >= 0) {
+    // Skip packets from other streams.
+    if (output_packet->stream_index != stream_index_) {
+      av_free_packet(output_packet);
+      continue;
+    }
+    return true;
+  }
+  return false;
+}
+
 }  // namespace media