Parsing of encoded duration for unencrypted opus streams.

media/formats/webm/webm_cluster_parser.h

Index: media/formats/webm/webm_cluster_parser.h
diff --git a/media/formats/webm/webm_cluster_parser.h b/media/formats/webm/webm_cluster_parser.h
index 2af102eaa0ce58b28909a6aa15fffd1bdbe4ed00..759fba9d6341800a6e58d1793435fdc03b11ef91 100644
--- a/media/formats/webm/webm_cluster_parser.h
+++ b/media/formats/webm/webm_cluster_parser.h
@@ -11,6 +11,7 @@
 #include <string>
 
 #include "base/memory/scoped_ptr.h"
+#include "media/base/audio_decoder_config.h"
 #include "media/base/media_export.h"
 #include "media/base/media_log.h"
 #include "media/base/stream_parser.h"
@@ -28,13 +29,17 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
 
   // Arbitrarily-chosen numbers to estimate the duration of a buffer if none is
   // set and there is not enough information to get a better estimate.
-  // TODO(wolenetz/acolwell): Parse audio codebook to determine missing audio
-  // frame durations. See http://crbug.com/351166.
   enum {
     kDefaultAudioBufferDurationInMs = 23,  // Common 1k samples @44.1kHz
     kDefaultVideoBufferDurationInMs = 42  // Low 24fps to reduce stalls
   };
 
+  // Opus packets encode the duration and other parameters in the 5 most
+  // significant bits of the first byte. The index in this array corresponds
+  // to the duration of each frame of the packet in microseconds. See
+  // https://tools.ietf.org/html/rfc6716#page-14
+  static const uint16_t kOpusFrameDurationsMu[];
+
  private:
   // Helper class that manages per-track state.
   class Track {
@@ -87,7 +92,7 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
     // block is a keyframe.
     // |data| contains the bytes in the block.
     // |size| indicates the number of bytes in |data|.
-    bool IsKeyframe(const uint8* data, int size) const;
+    bool IsKeyframe(const uint8_t* data, int size) const;
 
     base::TimeDelta default_duration() const { return default_duration_; }
 
@@ -143,6 +148,7 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
                     const std::set<int64>& ignored_tracks,
                     const std::string& audio_encryption_key_id,
                     const std::string& video_encryption_key_id,
+                    const AudioCodec audio_codec_,
                     const LogCB& log_cb);
   ~WebMClusterParser() override;
 
@@ -154,7 +160,7 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
   // Returns -1 if the parse fails.
   // Returns 0 if more data is needed.
   // Returns the number of bytes parsed on success.
-  int Parse(const uint8* buf, int size);
+  int Parse(const uint8_t* buf, int size);
 
   base::TimeDelta cluster_start_time() const { return cluster_start_time_; }
 
@@ -194,14 +200,24 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
   WebMParserClient* OnListStart(int id) override;
   bool OnListEnd(int id) override;
   bool OnUInt(int id, int64 val) override;
-  bool OnBinary(int id, const uint8* data, int size) override;
-
-  bool ParseBlock(bool is_simple_block, const uint8* buf, int size,
-                  const uint8* additional, int additional_size, int duration,
+  bool OnBinary(int id, const uint8_t* data, int size) override;
+
+  bool ParseBlock(bool is_simple_block,
+                  const uint8_t* buf,
+                  int size,
+                  const uint8_t* additional,
+                  int additional_size,
+                  int duration,
                   int64 discard_padding);
-  bool OnBlock(bool is_simple_block, int track_num, int timecode, int duration,
-               int flags, const uint8* data, int size,
-               const uint8* additional, int additional_size,
+  bool OnBlock(bool is_simple_block,
+               int track_num,
+               int timecode,
+               int duration,
+               int flags,
+               const uint8_t* data,
+               int size,
+               const uint8_t* additional,
+               int additional_size,
                int64 discard_padding);
 
   // Resets the Track objects associated with each text track.
@@ -227,21 +243,40 @@ class MEDIA_EXPORT WebMClusterParser : public WebMParserClient {
   // if that track num is not a text track.
   Track* FindTextTrack(int track_num);
 
+  // Attempts to read the duration from the encoded audio data, returning as
+  // TimeDelta or kNoTimestamp() if duration cannot be retrieved. This obviously
+  // violates layering rules, but is useful for MSE to know duration in cases
+  // where it isn't explicitly given and cannot be calculated for Blocks at the
+  // end of a Cluster (the next Cluster in playback-order may not be the next
+  // Cluster we parse, so we can't simply use the delta of the first Block in
+  // the next Cluster). Avoid calling if encrypted; may produce unexpected
+  // output. See implementation for supported codecs.
+  base::TimeDelta TryGetEncodedAudioDuration(const uint8_t* data, int size);
+
+  // Reads Opus packet header to determine packet duration. Duration returned
+  // as TimeDelta or kNoTimestamp() upon failure to read duration from packet.
+  base::TimeDelta ReadOpusDuration(const uint8_t* data, int size);
+
+  // Tracks the number of MEDIA_LOGs made in process of reading encoded
+  // duration. Useful to prevent log spam.
+  int num_duration_errors_;
+
   double timecode_multiplier_;  // Multiplier used to convert timecodes into
                                 // microseconds.
   std::set<int64> ignored_tracks_;
   std::string audio_encryption_key_id_;
   std::string video_encryption_key_id_;
+  const AudioCodec audio_codec_;
 
   WebMListParser parser_;
 
   int64 last_block_timecode_;
-  scoped_ptr<uint8[]> block_data_;
+  scoped_ptr<uint8_t[]> block_data_;
   int block_data_size_;
   int64 block_duration_;
   int64 block_add_id_;
 
-  scoped_ptr<uint8[]> block_additional_data_;
+  scoped_ptr<uint8_t[]> block_additional_data_;
   // Must be 0 if |block_additional_data_| is null. Must be > 0 if
   // |block_additional_data_| is NOT null.
   int block_additional_data_size_;