Add offset to tranport streams (MPEG2-TS, HLS Packed Audio)

Configurable with --transport_stream_offset_ms.

This is needed to compensate for possible negative timestamps in
inputs, which could happen on ISO-BMFF with EditLists.

Issue #112.

Change-Id: I0fce8766c9df2911b9bb859c1e54052a8ed2abfb

docs/source/documentation.rst

@@ -48,6 +48,8 @@ Synopsis
 
 .. include:: /options/mp4_output_options.rst
 
+.. include:: /options/transport_stream_output_options.rst
+
 .. include:: /options/dash_options.rst
 
 .. include:: /options/hls_options.rst

docs/source/options/transport_stream_output_options.rst

@@ -0,0 +1,10 @@
+Transport stream output options
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+--transport_stream_timestamp_offset_ms
+
+    Transport stream only (MPEG2-TS, HLS Packed Audio): A positive value, in
+    milliseconds, by which output timestamps are offset to compensate for
+    possible negative timestamps in the input. For example, timestamps from
+    ISO-BMFF after adjusted by EditList could be negative. In transport streams,
+    timestamps are not allowed to be less than zero. Default: 100ms.

packager/app/muxer_factory.cc

@@ -20,6 +20,8 @@ namespace media {
 
 MuxerFactory::MuxerFactory(const PackagingParams& packaging_params)
     : mp4_params_(packaging_params.mp4_output_params),
+      transport_stream_timestamp_offset_ms_(
+          packaging_params.transport_stream_timestamp_offset_ms),
       temp_dir_(packaging_params.temp_dir) {}
 
 std::shared_ptr<Muxer> MuxerFactory::CreateMuxer(
@@ -27,6 +29,8 @@ std::shared_ptr<Muxer> MuxerFactory::CreateMuxer(
     const StreamDescriptor& stream) {
   MuxerOptions options;
   options.mp4_params = mp4_params_;
+  options.transport_stream_timestamp_offset_ms =
+      transport_stream_timestamp_offset_ms_;
   options.temp_dir = temp_dir_;
   options.output_file_name = stream.output;
   options.segment_template = stream.segment_template;

packager/app/muxer_factory.h

@@ -46,8 +46,9 @@ class MuxerFactory {
   MuxerFactory(const MuxerFactory&) = delete;
   MuxerFactory& operator=(const MuxerFactory&) = delete;
 
-  Mp4OutputParams mp4_params_;
-  std::string temp_dir_;
+  const Mp4OutputParams mp4_params_;
+  const uint32_t transport_stream_timestamp_offset_ms_ = 0;
+  const std::string temp_dir_;
   base::Clock* clock_ = nullptr;
 };
 

packager/app/muxer_flags.cc

@@ -41,3 +41,10 @@ DEFINE_string(temp_dir,
 DEFINE_bool(mp4_include_pssh_in_stream,
             true,
             "MP4 only: include pssh in the encrypted stream.");
+DEFINE_int32(transport_stream_timestamp_offset_ms,
+             100,
+             "A positive value, in milliseconds, by which output timestamps "
+             "are offset to compensate for possible negative timestamps in the "
+             "input. For example, timestamps from ISO-BMFF after adjusted by "
+             "EditList could be negative. In transport streams, timestamps are "
+             "not allowed to be less than zero.");

packager/app/muxer_flags.h

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

packager/app/packager_main.cc

@@ -381,6 +381,9 @@ base::Optional<PackagingParams> GetPackagingParams() {
       FLAGS_generate_sidx_in_media_segments;
   mp4_params.include_pssh_in_stream = FLAGS_mp4_include_pssh_in_stream;
 
+  packaging_params.transport_stream_timestamp_offset_ms =
+      FLAGS_transport_stream_timestamp_offset_ms;
+
   packaging_params.output_media_info = FLAGS_output_media_info;
 
   MpdParams& mpd_params = packaging_params.mpd_params;

packager/app/test/packager_test.py

@@ -1486,7 +1486,8 @@ class PackagerFunctionalTest(PackagerAppTest):
     self._AssertStreamInfo(self.output[1], 'is_encrypted: true')
 
   def testHlsSegmentedWebVtt(self):
-    streams = self._GetStreams(['audio', 'video'], segmented=True)
+    streams = self._GetStreams(
+        ['audio', 'video'], output_format='ts', segmented=True)
     streams += self._GetStreams(
         ['text'], test_files=['bear-subtitle-english.vtt'], segmented=True)
 

packager/app/test/testdata/avc-aac-ts/output.mpd

@@ -6,8 +6,8 @@
       <Representation id="0" bandwidth="1023201" codecs="avc1.64001e" mimeType="video/MP2T" sar="1:1" frameRate="90000/0">
         <SegmentTemplate timescale="90000" media="bear-640x360-video-$Number$.ts" startNumber="1">
           <SegmentTimeline>
-            <S t="6006" d="90090" r="1"/>
-            <S t="186186" d="66066"/>
+            <S t="15006" d="90090" r="1"/>
+            <S t="195186" d="66066"/>
           </SegmentTimeline>
         </SegmentTemplate>
       </Representation>
@@ -17,9 +17,9 @@
         <AudioChannelConfiguration schemeIdUri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"/>
         <SegmentTemplate timescale="90000" media="bear-640x360-audio-$Number$.ts" startNumber="1">
           <SegmentTimeline>
-            <S t="3916" d="87771"/>
-            <S t="91688" d="89860"/>
-            <S t="181549" d="71052"/>
+            <S t="12916" d="87771"/>
+            <S t="100688" d="89860"/>
+            <S t="190549" d="71052"/>
           </SegmentTimeline>
         </SegmentTemplate>
       </Representation>