Deprecate --mp4_use_decoding_timestamp_in_timeline

It was implemented to workaround Chromium's DTS
https://crbug.com/398130, but the workaround does not really work in
all situations.

Remove it now as we already have another workaround available.

Change-Id: I291f559d78120fb743a6679b7d927e5bbc5b6b4e

docs/source/options/mp4_output_options.rst

@@ -7,10 +7,7 @@ MP4 output options
 
 --mp4_use_decoding_timestamp_in_timeline
 
-    If set, decoding timestamp instead of presentation timestamp will be used
+    Deprecated. Do not use.
-    when generating media timeline, e.g. timestamps in sidx and mpd. This is
-    to workaround a Chromium bug that decoding timestamp is used in buffered
-    range, https://crbug.com/398130. Default false.
 
 --num_subsegments_per_sidx <number>
 

packager/app/muxer_flags.cc

@@ -44,9 +44,3 @@ DEFINE_string(temp_dir,
 DEFINE_bool(mp4_include_pssh_in_stream,
             true,
             "MP4 only: include pssh in the encrypted stream.");
-DEFINE_bool(mp4_use_decoding_timestamp_in_timeline,
-            false,
-            "If set, decoding timestamp instead of presentation timestamp will "
-            "be used when generating media timeline, e.g. timestamps in sidx "
-            "and mpd. This is to workaround a Chromium bug that decoding "
-            "timestamp is used in buffered range, https://crbug.com/398130.");

packager/app/muxer_flags.h

@@ -19,6 +19,5 @@ DECLARE_bool(fragment_sap_aligned);
 DECLARE_int32(num_subsegments_per_sidx);
 DECLARE_string(temp_dir);
 DECLARE_bool(mp4_include_pssh_in_stream);
-DECLARE_bool(mp4_use_decoding_timestamp_in_timeline);
 
 #endif  // APP_MUXER_FLAGS_H_

packager/app/packager_main.cc

@@ -378,14 +378,6 @@ base::Optional<PackagingParams> GetPackagingParams() {
 
   Mp4OutputParams& mp4_params = packaging_params.mp4_output_params;
   mp4_params.num_subsegments_per_sidx = FLAGS_num_subsegments_per_sidx;
-  if (FLAGS_mp4_use_decoding_timestamp_in_timeline) {
-    LOG(WARNING) << "Flag --mp4_use_decoding_timestamp_in_timeline is set. "
-                    "Note that it is a temporary hack to workaround Chromium "
-                    "bug https://crbug.com/398130. The flag may be removed "
-                    "when the Chromium bug is fixed.";
-  }
-  mp4_params.use_decoding_timestamp_in_timeline =
-      FLAGS_mp4_use_decoding_timestamp_in_timeline;
   mp4_params.include_pssh_in_stream = FLAGS_mp4_include_pssh_in_stream;
 
   packaging_params.output_media_info = FLAGS_output_media_info;

packager/app/retired_flags.cc

@@ -28,6 +28,9 @@ DEFINE_string(playready_key,
               "",
               "This flag is deprecated. Use --enable_raw_key_encryption with "
               "--generate_playready_pssh to generate PlayReady PSSH.");
+DEFINE_bool(mp4_use_decoding_timestamp_in_timeline,
+            false,
+            "This flag is deprecated. Do not use.");
 
 // The current gflags library does not provide a way to check whether a flag is
 // set in command line. If a flag has a different value to its default value,
@@ -45,6 +48,12 @@ bool InformRetiredDefaultTrueFlag(const char* flagname, bool value) {
   return true;
 }
 
+bool InformRetiredDefaultFalseFlag(const char* flagname, bool value) {
+  if (value)
+    fprintf(stderr, "WARNING: %s is deprecated and ignored.\n", flagname);
+  return true;
+}
+
 bool InformRetiredDefaultDoubleFlag(const char* flagname, double value) {
   if (value != 0)
     fprintf(stderr, "WARNING: %s is deprecated and ignored.\n", flagname);
@@ -57,3 +66,5 @@ DEFINE_validator(webm_subsample_encryption, &InformRetiredDefaultTrueFlag);
 DEFINE_validator(availability_time_offset, &InformRetiredDefaultDoubleFlag);
 DEFINE_validator(playready_key_id, &InformRetiredStringFlag);
 DEFINE_validator(playready_key, &InformRetiredStringFlag);
+DEFINE_validator(mp4_use_decoding_timestamp_in_timeline,
+                 &InformRetiredDefaultFalseFlag);

packager/app/retired_flags.h

@@ -12,3 +12,4 @@ DECLARE_bool(webm_subsample_encryption);
 DECLARE_double(availability_time_offset);
 DECLARE_string(playready_key_id);
 DECLARE_string(playready_key);
+DECLARE_bool(mp4_use_decoding_timestamp_in_timeline);

packager/media/formats/mp4/fragmenter.cc

@@ -49,7 +49,6 @@ void NewSampleEncryptionEntry(const DecryptConfig& decrypt_config,
 Fragmenter::Fragmenter(std::shared_ptr<const StreamInfo> stream_info,
                        TrackFragment* traf)
     : stream_info_(std::move(stream_info)),
-      use_decoding_timestamp_in_timeline_(false),
       traf_(traf),
       seek_preroll_(GetSeekPreroll(*stream_info_)),
       fragment_initialized_(false),
@@ -103,7 +102,7 @@ Status Fragmenter::AddSample(const MediaSample& sample) {
   const int64_t pts = sample.pts();
   const int64_t dts = sample.dts();
 
-  const int64_t timestamp = use_decoding_timestamp_in_timeline_ ? dts : pts;
+  const int64_t timestamp = pts;
   // Set |earliest_presentation_time_| to |timestamp| if |timestamp| is smaller
   // or if it is not yet initialized (kInvalidTime > timestamp is always true).
   if (earliest_presentation_time_ > timestamp)

packager/media/formats/mp4/fragmenter.h

@@ -67,15 +67,6 @@ class Fragmenter {
     return key_frame_infos_;
   }
 
-  /// Set the flag use_decoding_timestamp_in_timeline, which if set to true, use
-  /// decoding timestamp instead of presentation timestamp in media timeline,
-  /// which is needed to workaround a Chromium bug that decoding timestamp is
-  /// used in buffered range, https://crbug.com/398130.
-  void set_use_decoding_timestamp_in_timeline(
-      bool use_decoding_timestamp_in_timeline) {
-    use_decoding_timestamp_in_timeline_ = use_decoding_timestamp_in_timeline;
-  }
-
   /// Set the flag allow_use_adjust_earliest_presentation_time, which if set to
   /// true, earlist_presentation_time (EPT) may be adjusted not to be smaller
   /// than the decoding timestamp (dts) for the first fragment.
@@ -100,7 +91,6 @@ class Fragmenter {
   bool StartsWithSAP() const;
 
   std::shared_ptr<const StreamInfo> stream_info_;
-  bool use_decoding_timestamp_in_timeline_;
   TrackFragment* traf_;
   uint64_t seek_preroll_;
   bool fragment_initialized_;

packager/media/formats/mp4/segmenter.cc

@@ -71,10 +71,6 @@ Status Segmenter::Initialize(
     fragmenters_[i].reset(new Fragmenter(streams[i], &moof_->tracks[i]));
   }
 
-  if (options_.mp4_params.use_decoding_timestamp_in_timeline) {
-    for (uint32_t i = 0; i < streams.size(); ++i)
-      fragmenters_[i]->set_use_decoding_timestamp_in_timeline(true);
-  }
   // Only allow |EPT| to be adjusted for the first file.
   if (options_.output_file_index == 0) {
     for (uint32_t i = 0; i < streams.size(); ++i)

packager/media/public/mp4_output_params.h

@@ -24,11 +24,6 @@ struct Mp4OutputParams {
   static constexpr int kNoSidxBoxInSegment = -1;
   static constexpr int kSingleSidxPerSegment = 0;
   int num_subsegments_per_sidx = kSingleSidxPerSegment;
-  /// Set the flag use_decoding_timestamp_in_timeline, which if set to true, use
-  /// decoding timestamp instead of presentation timestamp in media timeline,
-  /// which is needed to workaround a Chromium bug that decoding timestamp is
-  /// used in buffered range, https://crbug.com/398130.
-  bool use_decoding_timestamp_in_timeline = false;
 };
 
 }  // namespace shaka