Implement accurate seeking by decoding audio/video until we reach our desired timestamp.

media/filters/ffmpeg_audio_decoder.cc

 // Copyright (c) 2010 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 "media/base/callback.h"
 #include "media/base/data_buffer.h"
 #include "media/base/limits.h"
 #include "media/ffmpeg/ffmpeg_common.h"
@@ skipping 137 matching lines @@
   *reinterpret_cast<int32*>(p) = sample;
 }
 #endif
 static void ConvertAudioF32ToS32(void* buffer, int buffer_size) {
   for (int i = 0; i < buffer_size / 4; ++i) {
     FloatToIntSaturate(reinterpret_cast<float*>(buffer) + i);
   }
 }
 
 void FFmpegAudioDecoder::DoDecode(Buffer* input) {
+  // FFmpeg tends to seek Ogg audio streams in the middle of nowhere, giving us
+  // a whole bunch of AV_NOPTS_VALUE packets.  Discard them until we find
+  // something valid.
+  // TODO(hclam): remove this once fixing the issue in FFmpeg.
+  if (input->GetTimestamp() == StreamSample::kInvalidTimestamp &&
+      estimated_next_timestamp_ == StreamSample::kInvalidTimestamp &&
+      !input->IsEndOfStream()) {
+    DecoderBase<AudioDecoder, Buffer>::OnDecodeComplete();
+    return;
+  }
+
   // Due to FFmpeg API changes we no longer have const read-only pointers.
   AVPacket packet;
   av_init_packet(&packet);
   packet.data = const_cast<uint8*>(input->GetData());
   packet.size = input->GetDataSize();
 
   int16_t* output_buffer = reinterpret_cast<int16_t*>(output_buffer_.get());
   int output_buffer_size = kOutputBufferSize;
   int result = avcodec_decode_audio3(codec_context_,
                                      output_buffer,
@@ skipping 77 matching lines @@
 base::TimeDelta FFmpegAudioDecoder::CalculateDuration(size_t size) {
   int64 denominator = codec_context_->channels *
       av_get_bits_per_sample_format(codec_context_->sample_fmt) / 8 *
       codec_context_->sample_rate;
   double microseconds = size /
       (denominator / static_cast<double>(base::Time::kMicrosecondsPerSecond));
   return base::TimeDelta::FromMicroseconds(static_cast<int64>(microseconds));
 }
 
 }  // namespace