Support I-Frames only playlist in MediaPlaylist

Issue: #287

Change-Id: I204774fd87cf9a159a4448ba3457db5ab17f7889

packager/hls/base/master_playlist.cc

@@ -76,12 +76,12 @@ MasterPlaylist::~MasterPlaylist() {}
 void MasterPlaylist::AddMediaPlaylist(MediaPlaylist* media_playlist) {
   DCHECK(media_playlist);
   switch (media_playlist->stream_type()) {
-    case MediaPlaylist::MediaPlaylistStreamType::kPlayListAudio: {
+    case MediaPlaylist::MediaPlaylistStreamType::kAudio: {
       const std::string& group_id = media_playlist->group_id();
       audio_playlist_groups_[group_id].push_back(media_playlist);
       break;
     }
-    case MediaPlaylist::MediaPlaylistStreamType::kPlayListVideo: {
+    case MediaPlaylist::MediaPlaylistStreamType::kVideo: {
       video_playlists_.push_back(media_playlist);
       break;
     }

packager/hls/base/master_playlist_unittest.cc

@@ -64,7 +64,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistOneVideo) {
   MockMediaPlaylist mock_playlist(kVodPlaylist, "media1.m3u8", "somename",
                                   "somegroupid");
   mock_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListVideo);
+      MediaPlaylist::MediaPlaylistStreamType::kVideo);
   mock_playlist.SetCodecForTesting(codec);
   EXPECT_CALL(mock_playlist, Bitrate()).WillOnce(Return(435889));
   EXPECT_CALL(mock_playlist, GetDisplayResolution(NotNull(), NotNull()))
@@ -95,7 +95,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistVideoAndAudio) {
   MockMediaPlaylist sd_video_playlist(kVodPlaylist, "sd.m3u8", "somename",
                                       "somegroupid");
   sd_video_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListVideo);
+      MediaPlaylist::MediaPlaylistStreamType::kVideo);
   sd_video_playlist.SetCodecForTesting(sd_video_codec);
   EXPECT_CALL(sd_video_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -111,7 +111,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistVideoAndAudio) {
   MockMediaPlaylist hd_video_playlist(kVodPlaylist, "hd.m3u8", "somename",
                                       "somegroupid");
   hd_video_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListVideo);
+      MediaPlaylist::MediaPlaylistStreamType::kVideo);
   hd_video_playlist.SetCodecForTesting(hd_video_codec);
   EXPECT_CALL(hd_video_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -131,7 +131,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistVideoAndAudio) {
   EXPECT_CALL(english_playlist, GetLanguage()).WillRepeatedly(Return("en"));
   EXPECT_CALL(english_playlist, GetNumChannels()).WillRepeatedly(Return(2));
   english_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListAudio);
+      MediaPlaylist::MediaPlaylistStreamType::kAudio);
   english_playlist.SetCodecForTesting(audio_codec);
   EXPECT_CALL(english_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -146,7 +146,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistVideoAndAudio) {
   EXPECT_CALL(spanish_playlist, GetLanguage()).WillRepeatedly(Return("es"));
   EXPECT_CALL(spanish_playlist, GetNumChannels()).WillRepeatedly(Return(5));
   spanish_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListAudio);
+      MediaPlaylist::MediaPlaylistStreamType::kAudio);
   spanish_playlist.SetCodecForTesting(audio_codec);
   EXPECT_CALL(spanish_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -187,7 +187,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistMultipleAudioGroups) {
   MockMediaPlaylist video_playlist(kVodPlaylist, "video.m3u8", "somename",
                                    "somegroupid");
   video_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListVideo);
+      MediaPlaylist::MediaPlaylistStreamType::kVideo);
   video_playlist.SetCodecForTesting(video_codec);
   EXPECT_CALL(video_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -205,7 +205,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistMultipleAudioGroups) {
   EXPECT_CALL(eng_lo_playlist, GetLanguage()).WillRepeatedly(Return("en"));
   EXPECT_CALL(eng_lo_playlist, GetNumChannels()).WillRepeatedly(Return(1));
   eng_lo_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListAudio);
+      MediaPlaylist::MediaPlaylistStreamType::kAudio);
   eng_lo_playlist.SetCodecForTesting(audio_codec_lo);
   EXPECT_CALL(eng_lo_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -221,7 +221,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistMultipleAudioGroups) {
   EXPECT_CALL(eng_hi_playlist, GetLanguage()).WillRepeatedly(Return("en"));
   EXPECT_CALL(eng_hi_playlist, GetNumChannels()).WillRepeatedly(Return(8));
   eng_hi_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListAudio);
+      MediaPlaylist::MediaPlaylistStreamType::kAudio);
   eng_hi_playlist.SetCodecForTesting(audio_codec_hi);
   EXPECT_CALL(eng_hi_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -262,7 +262,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistSameAudioGroupSameLanguage) {
   MockMediaPlaylist video_playlist(kVodPlaylist, "video.m3u8", "somename",
                                    "somegroupid");
   video_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListVideo);
+      MediaPlaylist::MediaPlaylistStreamType::kVideo);
   video_playlist.SetCodecForTesting(video_codec);
   EXPECT_CALL(video_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -279,7 +279,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistSameAudioGroupSameLanguage) {
   EXPECT_CALL(eng_lo_playlist, GetLanguage()).WillRepeatedly(Return("en"));
   EXPECT_CALL(eng_lo_playlist, GetNumChannels()).WillRepeatedly(Return(1));
   eng_lo_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListAudio);
+      MediaPlaylist::MediaPlaylistStreamType::kAudio);
   eng_lo_playlist.SetCodecForTesting(audio_codec);
   EXPECT_CALL(eng_lo_playlist, Bitrate())
       .Times(AtLeast(1))
@@ -294,7 +294,7 @@ TEST_F(MasterPlaylistTest, WriteMasterPlaylistSameAudioGroupSameLanguage) {
   EXPECT_CALL(eng_hi_playlist, GetLanguage()).WillRepeatedly(Return("en"));
   EXPECT_CALL(eng_hi_playlist, GetNumChannels()).WillRepeatedly(Return(8));
   eng_hi_playlist.SetStreamTypeForTesting(
-      MediaPlaylist::MediaPlaylistStreamType::kPlayListAudio);
+      MediaPlaylist::MediaPlaylistStreamType::kAudio);
   eng_hi_playlist.SetCodecForTesting(audio_codec);
   EXPECT_CALL(eng_hi_playlist, Bitrate())
       .Times(AtLeast(1))

packager/hls/base/media_playlist.cc

@@ -59,9 +59,11 @@ std::string CreateExtXMap(const MediaInfo& media_info) {
   return ext_x_map;
 }
 
-std::string CreatePlaylistHeader(const MediaInfo& media_info,
+std::string CreatePlaylistHeader(
+    const MediaInfo& media_info,
     uint32_t target_duration,
     HlsPlaylistType type,
+    MediaPlaylist::MediaPlaylistStreamType stream_type,
     int media_sequence_number,
     int discontinuity_sequence_number) {
   const std::string version = GetPackagerVersion();
@@ -100,6 +102,10 @@ std::string CreatePlaylistHeader(const MediaInfo& media_info,
     default:
       NOTREACHED() << "Unexpected MediaPlaylistType " << static_cast<int>(type);
   }
+  if (stream_type ==
+      MediaPlaylist::MediaPlaylistStreamType::kVideoIFramesOnly) {
+    base::StringAppendF(&header, "#EXT-X-I-FRAMES-ONLY\n");
+  }
 
   // Put EXT-X-MAP at the end since the rest of the playlist is about the
   // segment and key info.
@@ -319,10 +325,10 @@ bool MediaPlaylist::SetMediaInfo(const MediaInfo& media_info) {
   }
 
   if (media_info.has_video_info()) {
-    stream_type_ = MediaPlaylistStreamType::kPlayListVideo;
+    stream_type_ = MediaPlaylistStreamType::kVideo;
     codec_ = media_info.video_info().codec();
   } else if (media_info.has_audio_info()) {
-    stream_type_ = MediaPlaylistStreamType::kPlayListAudio;
+    stream_type_ = MediaPlaylistStreamType::kAudio;
     codec_ = media_info.audio_info().codec();
   } else {
     NOTIMPLEMENTED();
@@ -331,6 +337,7 @@ bool MediaPlaylist::SetMediaInfo(const MediaInfo& media_info) {
 
   time_scale_ = time_scale;
   media_info_ = media_info;
+  use_byte_range_ = !media_info_.has_segment_template();
   return true;
 }
 
@@ -339,32 +346,45 @@ void MediaPlaylist::AddSegment(const std::string& file_name,
                                uint64_t duration,
                                uint64_t start_byte_offset,
                                uint64_t size) {
-  if (time_scale_ == 0) {
+  if (stream_type_ == MediaPlaylistStreamType::kVideoIFramesOnly) {
-    LOG(WARNING) << "Timescale is not set and the duration for " << duration
+    if (key_frames_.empty())
-                 << " cannot be calculated. The output will be wrong.";
-
-    entries_.emplace_back(new SegmentInfoEntry(
-        file_name, 0.0, 0.0, !media_info_.has_segment_template(),
-        start_byte_offset, size, previous_segment_end_offset_));
       return;
+    // Skip the last entry as the duration of the key frames are defined by the
+    // next key frame, which we don't know yet.
+    for (auto iter = key_frames_.begin(); iter != std::prev(key_frames_.end());
+         ++iter) {
+      const std::string& segment_file_name =
+          iter->segment_file_name.empty() ? file_name : iter->segment_file_name;
+      AddSegmentInfoEntry(segment_file_name, iter->timestamp, iter->duration,
+                          iter->start_byte_offset, iter->size);
     }
 
-  const double start_time_seconds =
+    key_frames_.erase(key_frames_.begin(), std::prev(key_frames_.end()));
-      static_cast<double>(start_time) / time_scale_;
+    KeyFrameInfo& key_frame = key_frames_.front();
-  const double segment_duration_seconds =
+    key_frame.segment_file_name = file_name;
-      static_cast<double>(duration) / time_scale_;
+    key_frame.duration = start_time + duration - key_frame.timestamp;
-  if (segment_duration_seconds > longest_segment_duration_)
+    return;
-    longest_segment_duration_ = segment_duration_seconds;
+  }
+  return AddSegmentInfoEntry(file_name, start_time, duration, start_byte_offset,
+                             size);
+}
 
-  const int kBitsInByte = 8;
+void MediaPlaylist::AddKeyFrame(uint64_t timestamp,
-  const uint64_t bitrate = kBitsInByte * size / segment_duration_seconds;
+                                uint64_t start_byte_offset,
-  max_bitrate_ = std::max(max_bitrate_, bitrate);
+                                uint64_t size) {
-  entries_.emplace_back(new SegmentInfoEntry(
+  if (stream_type_ != MediaPlaylistStreamType::kVideoIFramesOnly) {
-      file_name, start_time_seconds, segment_duration_seconds,
+    if (stream_type_ != MediaPlaylistStreamType::kVideo) {
-      !media_info_.has_segment_template(), start_byte_offset, size,
+      LOG(WARNING)
-      previous_segment_end_offset_));
+          << "I-Frames Only playlist applies to video renditions only.";
-  previous_segment_end_offset_ = start_byte_offset + size - 1;
+      return;
-  SlideWindow();
+    }
+    stream_type_ = MediaPlaylistStreamType::kVideoIFramesOnly;
+    use_byte_range_ = true;
+  }
+  if (!key_frames_.empty()) {
+    key_frames_.back().duration = timestamp - key_frames_.back().timestamp;
+  }
+  key_frames_.push_back({timestamp, start_byte_offset, size});
 }
 
 void MediaPlaylist::AddEncryptionInfo(MediaPlaylist::EncryptionMethod method,
@@ -389,13 +409,24 @@ void MediaPlaylist::AddPlacementOpportunity() {
 }
 
 bool MediaPlaylist::WriteToFile(const std::string& file_path) {
+  if (!key_frames_.empty() && playlist_type_ == HlsPlaylistType::kVod) {
+    // Flush remaining key frames. This assumes |WriteToFile| is only called
+    // once at the end of the file in VOD.
+    CHECK_EQ(key_frames_.size(), 1u);
+    const KeyFrameInfo& key_frame = key_frames_.front();
+    AddSegmentInfoEntry(key_frame.segment_file_name, key_frame.timestamp,
+                        key_frame.duration, key_frame.start_byte_offset,
+                        key_frame.size);
+    key_frames_.clear();
+  }
+
   if (!target_duration_set_) {
     SetTargetDuration(ceil(GetLongestSegmentDuration()));
   }
 
   std::string header = CreatePlaylistHeader(
-      media_info_, target_duration_, playlist_type_, media_sequence_number_,
+      media_info_, target_duration_, playlist_type_, stream_type_,
-      discontinuity_sequence_number_);
+      media_sequence_number_, discontinuity_sequence_number_);
 
   std::string body;
   for (const auto& entry : entries_)
@@ -472,6 +503,38 @@ bool MediaPlaylist::GetDisplayResolution(uint32_t* width,
   return false;
 }
 
+void MediaPlaylist::AddSegmentInfoEntry(const std::string& segment_file_name,
+                                        uint64_t start_time,
+                                        uint64_t duration,
+                                        uint64_t start_byte_offset,
+                                        uint64_t size) {
+  if (time_scale_ == 0) {
+    LOG(WARNING) << "Timescale is not set and the duration for " << duration
+                 << " cannot be calculated. The output will be wrong.";
+
+    entries_.emplace_back(new SegmentInfoEntry(
+        segment_file_name, 0.0, 0.0, use_byte_range_, start_byte_offset, size,
+        previous_segment_end_offset_));
+    return;
+  }
+
+  const double start_time_seconds =
+      static_cast<double>(start_time) / time_scale_;
+  const double segment_duration_seconds =
+      static_cast<double>(duration) / time_scale_;
+  if (segment_duration_seconds > longest_segment_duration_)
+    longest_segment_duration_ = segment_duration_seconds;
+
+  const int kBitsInByte = 8;
+  const uint64_t bitrate = kBitsInByte * size / segment_duration_seconds;
+  max_bitrate_ = std::max(max_bitrate_, bitrate);
+  entries_.emplace_back(new SegmentInfoEntry(
+      segment_file_name, start_time_seconds, segment_duration_seconds,
+      use_byte_range_, start_byte_offset, size, previous_segment_end_offset_));
+  previous_segment_end_offset_ = start_byte_offset + size - 1;
+  SlideWindow();
+}
+
 void MediaPlaylist::SlideWindow() {
   DCHECK(!entries_.empty());
   if (time_shift_buffer_depth_ <= 0.0 ||

packager/hls/base/media_playlist.h

@@ -45,10 +45,11 @@ class HlsEntry {
 class MediaPlaylist {
  public:
   enum class MediaPlaylistStreamType {
-    kPlaylistUnknown,
+    kUnknown,
-    kPlayListAudio,
+    kAudio,
-    kPlayListVideo,
+    kVideo,
-    kPlayListSubtitle,
+    kVideoIFramesOnly,
+    kSubtitle,
   };
   enum class EncryptionMethod {
     kNone,           // No encryption, i.e. clear.
@@ -104,6 +105,16 @@ class MediaPlaylist {
                           uint64_t start_byte_offset,
                           uint64_t size);
 
+  /// Keyframes must be added in order. It is also called before the containing
+  /// segment being called.
+  /// @param timestamp is the timestamp of the key frame in timescale of the
+  ///        media.
+  /// @param start_byte_offset is the offset of where the key frame starts.
+  /// @param size is size in bytes.
+  virtual void AddKeyFrame(uint64_t timestamp,
+                           uint64_t start_byte_offset,
+                           uint64_t size);
+
   /// All segments added after calling this method must be decryptable with
   /// the key that can be fetched from |url|, until calling this again.
   /// @param method is the encryption method.
@@ -168,6 +179,12 @@ class MediaPlaylist {
   virtual bool GetDisplayResolution(uint32_t* width, uint32_t* height) const;
 
  private:
+  // Add a SegmentInfoEntry (#EXTINF).
+  void AddSegmentInfoEntry(const std::string& segment_file_name,
+                           uint64_t start_time,
+                           uint64_t duration,
+                           uint64_t start_byte_offset,
+                           uint64_t size);
   // Remove elements from |entries_| for live profile. Increments
   // |sequence_number_| by the number of segments removed.
   void SlideWindow();
@@ -179,8 +196,9 @@ class MediaPlaylist {
   const std::string name_;
   const std::string group_id_;
   MediaInfo media_info_;
-  MediaPlaylistStreamType stream_type_ =
+  MediaPlaylistStreamType stream_type_ = MediaPlaylistStreamType::kUnknown;
-      MediaPlaylistStreamType::kPlaylistUnknown;
+  // Whether to use byte range for SegmentInfoEntry.
+  bool use_byte_range_ = false;
   std::string codec_;
   int media_sequence_number_ = 0;
   bool inserted_discontinuity_tag_ = false;
@@ -201,6 +219,16 @@ class MediaPlaylist {
 
   std::list<std::unique_ptr<HlsEntry>> entries_;
 
+  // Used by kVideoIFrameOnly playlists to track the i-frames (key frames).
+  struct KeyFrameInfo {
+    uint64_t timestamp;
+    uint64_t start_byte_offset;
+    uint64_t size;
+    uint64_t duration;
+    std::string segment_file_name;
+  };
+  std::list<KeyFrameInfo> key_frames_;
+
   DISALLOW_COPY_AND_ASSIGN(MediaPlaylist);
 };
 

packager/hls/base/media_playlist_unittest.cc

@@ -771,5 +771,101 @@ TEST_F(EventMediaPlaylistTest, Basic) {
   ASSERT_FILE_STREQ(kMemoryFilePath, kExpectedOutput);
 }
 
+class IFrameMediaPlaylistTest : public MediaPlaylistTest {};
+
+TEST_F(IFrameMediaPlaylistTest, MediaPlaylistType) {
+  ASSERT_TRUE(media_playlist_.SetMediaInfo(valid_video_media_info_));
+  EXPECT_EQ(MediaPlaylist::MediaPlaylistStreamType::kVideo,
+            media_playlist_.stream_type());
+  media_playlist_.AddKeyFrame(0, 1000, 2345);
+  // Playlist stream type is updated to I-Frames only after seeing
+  // |AddKeyFrame|.
+  EXPECT_EQ(MediaPlaylist::MediaPlaylistStreamType::kVideoIFramesOnly,
+            media_playlist_.stream_type());
+}
+
+TEST_F(IFrameMediaPlaylistTest, SingleSegment) {
+  valid_video_media_info_.set_media_file_name("file.mp4");
+  valid_video_media_info_.mutable_init_range()->set_begin(0);
+  valid_video_media_info_.mutable_init_range()->set_end(500);
+
+  ASSERT_TRUE(media_playlist_.SetMediaInfo(valid_video_media_info_));
+  media_playlist_.AddKeyFrame(0, 1000, 2345);
+  media_playlist_.AddKeyFrame(2 * kTimeScale, 5000, 6345);
+  media_playlist_.AddSegment("file.mp4", 0, 10 * kTimeScale, kZeroByteOffset,
+                             kMBytes);
+  media_playlist_.AddKeyFrame(11 * kTimeScale, kMBytes + 1000, 2345);
+  media_playlist_.AddKeyFrame(15 * kTimeScale, kMBytes + 3345, 12345);
+  media_playlist_.AddSegment("file.mp4", 10 * kTimeScale, 10 * kTimeScale,
+                             1001000, 2 * kMBytes);
+
+  const char kExpectedOutput[] =
+      "#EXTM3U\n"
+      "#EXT-X-VERSION:6\n"
+      "## Generated with https://github.com/google/shaka-packager version "
+      "test\n"
+      "#EXT-X-TARGETDURATION:9\n"
+      "#EXT-X-PLAYLIST-TYPE:VOD\n"
+      "#EXT-X-I-FRAMES-ONLY\n"
+      "#EXT-X-MAP:URI=\"file.mp4\",BYTERANGE=\"501@0\"\n"
+      "#EXTINF:2.000,\n"
+      "#EXT-X-BYTERANGE:2345@1000\n"
+      "file.mp4\n"
+      "#EXTINF:9.000,\n"
+      "#EXT-X-BYTERANGE:6345@5000\n"
+      "file.mp4\n"
+      "#EXTINF:4.000,\n"
+      "#EXT-X-BYTERANGE:2345@1001000\n"
+      "file.mp4\n"
+      "#EXTINF:5.000,\n"
+      "#EXT-X-BYTERANGE:12345\n"
+      "file.mp4\n"
+      "#EXT-X-ENDLIST\n";
+
+  const char kMemoryFilePath[] = "memory://media.m3u8";
+  EXPECT_TRUE(media_playlist_.WriteToFile(kMemoryFilePath));
+  ASSERT_FILE_STREQ(kMemoryFilePath, kExpectedOutput);
+}
+
+TEST_F(IFrameMediaPlaylistTest, MultiSegment) {
+  valid_video_media_info_.set_reference_time_scale(90000);
+  ASSERT_TRUE(media_playlist_.SetMediaInfo(valid_video_media_info_));
+
+  media_playlist_.AddKeyFrame(0, 1000, 2345);
+  media_playlist_.AddKeyFrame(2 * kTimeScale, 5000, 6345);
+  media_playlist_.AddSegment("file1.ts", 0, 10 * kTimeScale, kZeroByteOffset,
+                             kMBytes);
+  media_playlist_.AddKeyFrame(11 * kTimeScale, 1000, 2345);
+  media_playlist_.AddKeyFrame(15 * kTimeScale, 3345, 12345);
+  media_playlist_.AddSegment("file2.ts", 10 * kTimeScale, 30 * kTimeScale,
+                             kZeroByteOffset, 5 * kMBytes);
+
+  const char kExpectedOutput[] =
+      "#EXTM3U\n"
+      "#EXT-X-VERSION:6\n"
+      "## Generated with https://github.com/google/shaka-packager version "
+      "test\n"
+      "#EXT-X-TARGETDURATION:25\n"
+      "#EXT-X-PLAYLIST-TYPE:VOD\n"
+      "#EXT-X-I-FRAMES-ONLY\n"
+      "#EXTINF:2.000,\n"
+      "#EXT-X-BYTERANGE:2345@1000\n"
+      "file1.ts\n"
+      "#EXTINF:9.000,\n"
+      "#EXT-X-BYTERANGE:6345@5000\n"
+      "file1.ts\n"
+      "#EXTINF:4.000,\n"
+      "#EXT-X-BYTERANGE:2345@1000\n"
+      "file2.ts\n"
+      "#EXTINF:25.000,\n"
+      "#EXT-X-BYTERANGE:12345\n"
+      "file2.ts\n"
+      "#EXT-X-ENDLIST\n";
+
+  const char kMemoryFilePath[] = "memory://media.m3u8";
+  EXPECT_TRUE(media_playlist_.WriteToFile(kMemoryFilePath));
+  ASSERT_FILE_STREQ(kMemoryFilePath, kExpectedOutput);
+}
+
 }  // namespace hls
 }  // namespace shaka