Use max bitrate for MediaPlaylist bandwidth calculation

- HLS expects max for VOD.

Change-Id: I91e9e07a27abe7167efeefc99aaada2acbed9314

packager/hls/base/media_playlist.cc

@@ -182,10 +182,9 @@ void MediaPlaylist::AddSegment(const std::string& file_name,
   if (segment_duration_seconds > longest_segment_duration_)
     longest_segment_duration_ = segment_duration_seconds;
 
-  total_duration_in_seconds_ += segment_duration_seconds;
-  total_segments_size_ += size;
-  ++total_num_segments_;
-
+  const int kBitsInByte = 8;
+  const uint64_t bitrate = kBitsInByte * size / segment_duration_seconds;
+  max_bitrate_ = std::max(max_bitrate_, bitrate);
   entries_.push_back(new SegmentInfoEntry(file_name, segment_duration_seconds));
 }
 
@@ -313,12 +312,7 @@ bool MediaPlaylist::WriteToFile(media::File* file) {
 uint64_t MediaPlaylist::Bitrate() const {
   if (media_info_.has_bandwidth())
     return media_info_.bandwidth();
-  if (total_duration_in_seconds_ == 0.0)
-    return 0;
-  if (total_segments_size_ == 0)
-    return 0;
-  const int kBytesToBits = 8;
-  return total_segments_size_ * kBytesToBits / total_duration_in_seconds_;
+  return max_bitrate_;
 }
 
 double MediaPlaylist::GetLongestSegmentDuration() const {

packager/hls/base/media_playlist.h

@@ -132,8 +132,7 @@ class MediaPlaylist {
   virtual bool WriteToFile(media::File* file);
 
   /// If bitrate is specified in MediaInfo then it will use that value.
-  /// Otherwise, it is calculated from the duration and the size of the
-  /// segments added to this object.
+  /// Otherwise, returns the max bitrate.
   /// @return the bitrate (in bits per second) of this MediaPlaylist.
   virtual uint64_t Bitrate() const;
 
@@ -165,10 +164,8 @@ class MediaPlaylist {
   double longest_segment_duration_ = 0.0;
   uint32_t time_scale_ = 0;
 
-  // The sum of the size of the segments listed in this playlist (in bytes).
-  uint64_t total_segments_size_ = 0;
+  uint64_t max_bitrate_ = 0;
   double total_duration_in_seconds_ = 0.0;
-  int total_num_segments_;
 
   // See SetTargetDuration() comments.
   bool target_duration_set_ = false;

packager/hls/base/media_playlist_unittest.cc

@@ -148,8 +148,8 @@ TEST_F(MediaPlaylistTest, GetBitrateFromSegments) {
   // 20 seconds, 5MB.
   media_playlist_.AddSegment("file2.ts", 1800000, 5000000);
 
-  // 200KB per second which is 1600K bits / sec.
-  EXPECT_EQ(1600000u, media_playlist_.Bitrate());
+  // Max bitrate is 2000Kb/s.
+  EXPECT_EQ(2000000u, media_playlist_.Bitrate());
 }
 
 TEST_F(MediaPlaylistTest, GetLongestSegmentDuration) {