Parsing of encoded duration for unencrypted opus streams.

media/formats/webm/opus_packet_builder.h

Index: media/formats/webm/opus_packet_builder.h
diff --git a/media/formats/webm/opus_packet_builder.h b/media/formats/webm/opus_packet_builder.h
new file mode 100644
index 0000000000000000000000000000000000000000..af76b49a398cd564003ffa41533cc3c4b3270bec
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+++ b/media/formats/webm/opus_packet_builder.h
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+// Copyright (c) 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.
+
+#ifndef MEDIA_FORMATS_WEBM_OPUS_PACKET_BUILDER_H_
+#define MEDIA_FORMATS_WEBM_OPUS_PACKET_BUILDER_H_
+
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+
+namespace media {
+
+// From Opus RFC. See https://tools.ietf.org/html/rfc6716#page-14
+enum OpusConstants {
+  kNumPossibleOpusConfigs = 32,
+  kMinOpusPacketFrameCount = 1,
+  kMaxOpusPacketFrameCount = 48
+};
+
+class OpusPacket {
+ public:
+  OpusPacket(uint8_t config, uint8_t frame_count, bool is_VBR);
+  ~OpusPacket();
+
+  const uint8_t* data() const;
+  int size() const;
+  double duration_ms() const;
+
+ private:
+  std::vector<uint8_t> data_;
+  double duration_ms_;
+
+  DISALLOW_COPY_AND_ASSIGN(OpusPacket);
+};
+
+// Builds an exhaustive collection of Opus packet configurations.
+ScopedVector<OpusPacket> BuildAllOpusPackets();
+
+}  // namespace media
+
+#endif  // MEDIA_FORMATS_WEBM_OPUS_PACKET_BUILDER_H_