feat: Parse MPEG-TS PMT ES language and maximum bitrate descriptors (#369) (#1311)

Part of https://github.com/shaka-project/shaka-packager/issues/369

This adds read support for some MPEG-TS PMT elementary stream
descriptors:
- ISO639 Language Descriptor providing language code and audio type
- Maximum Bitrate Descriptor providing peak stream bandwidth

Those metadata are propagated to StreamInfo structures:
- StreamInfo.language field
- AudioStreamMetadata.max_bitrate field for audio streams
- audio type is currently not propagated - corresponding field has to be
added to AudioStreamMetadata

Test vector file containing those descriptors is provided.

packager/media/base/audio_stream_info.h

@@ -60,6 +60,10 @@ class AudioStreamInfo : public StreamInfo {
     sampling_frequency_ = sampling_frequency;
   }
 
+  void set_max_bitrate(const uint32_t max_bitrate) {
+    max_bitrate_ = max_bitrate;
+  }
+
   /// @param audio_object_type is only used by AAC Codec, ignored otherwise.
   /// @return The codec string.
   static std::string GetCodecString(Codec codec, uint8_t audio_object_type);

packager/media/formats/mp2t/CMakeLists.txt

@@ -33,6 +33,7 @@ add_library(mp2t STATIC
   pes_packet_generator.h
   program_map_table_writer.cc
   program_map_table_writer.h
+  ts_audio_type.h
   ts_muxer.cc
   ts_muxer.h
   ts_packet.cc

packager/media/formats/mp2t/mp2t_media_parser.cc

@@ -19,6 +19,7 @@
 #include <packager/media/formats/mp2t/es_parser_h264.h>
 #include <packager/media/formats/mp2t/es_parser_h265.h>
 #include <packager/media/formats/mp2t/mp2t_common.h>
+#include <packager/media/formats/mp2t/ts_audio_type.h>
 #include <packager/media/formats/mp2t/ts_packet.h>
 #include <packager/media/formats/mp2t/ts_section.h>
 #include <packager/media/formats/mp2t/ts_section_pat.h>
@@ -274,7 +275,8 @@ void Mp2tMediaParser::RegisterPmt(int program_number, int pmt_pid) {
   DVLOG(1) << "Create a new PMT parser";
   std::unique_ptr<TsSection> pmt_section_parser(new TsSectionPmt(std::bind(
       &Mp2tMediaParser::RegisterPes, this, pmt_pid, std::placeholders::_1,
-      std::placeholders::_2, std::placeholders::_3, std::placeholders::_4)));
+      std::placeholders::_2, std::placeholders::_3, std::placeholders::_4,
+      std::placeholders::_5, std::placeholders::_6, std::placeholders::_7)));
   std::unique_ptr<PidState> pmt_pid_state(
       new PidState(pmt_pid, PidState::kPidPmt, std::move(pmt_section_parser)));
   pmt_pid_state->Enable();
@@ -284,13 +286,19 @@ void Mp2tMediaParser::RegisterPmt(int program_number, int pmt_pid) {
 void Mp2tMediaParser::RegisterPes(int pmt_pid,
                                   int pes_pid,
                                   TsStreamType stream_type,
+                                  uint32_t max_bitrate,
+                                  const std::string& lang,
+                                  TsAudioType audio_type,
                                   const uint8_t* descriptor,
                                   size_t descriptor_length) {
   if (pids_.count(pes_pid) != 0)
     return;
   DVLOG(1) << "RegisterPes:"
            << " pes_pid=" << pes_pid << " stream_type=" << std::hex
-           << static_cast<int>(stream_type) << std::dec;
+           << static_cast<int>(stream_type) << std::dec
+           << "max_bitrate=" << max_bitrate << " lang=" << lang
+           << "audio_type=" << std::hex << static_cast<int>(audio_type)
+           << std::dec;
 
   // Create a stream parser corresponding to the stream type.
   PidState::PidType pid_type = PidState::kPidVideoPes;
@@ -340,6 +348,10 @@ void Mp2tMediaParser::RegisterPes(int pmt_pid,
       new PidState(pes_pid, pid_type, std::move(pes_section_parser)));
   pes_pid_state->Enable();
   pids_.emplace(pes_pid, std::move(pes_pid_state));
+
+  // Store PES metadata.
+  pes_metadata_.insert(
+      std::make_pair(pes_pid, PesMetadata{max_bitrate, lang, audio_type}));
 }
 
 void Mp2tMediaParser::OnNewStreamInfo(
@@ -358,6 +370,17 @@ void Mp2tMediaParser::OnNewStreamInfo(
 
   if (new_stream_info) {
     // Set the stream configuration information for the PID.
+    auto pes_metadata = pes_metadata_.find(pes_pid);
+    DCHECK(pes_metadata != pes_metadata_.end());
+    if (!pes_metadata->second.language.empty())
+      new_stream_info->set_language(pes_metadata->second.language);
+    if (new_stream_info->stream_type() == kStreamAudio) {
+      auto* audio_info = static_cast<AudioStreamInfo*>(new_stream_info.get());
+      audio_info->set_max_bitrate(pes_metadata->second.max_bitrate);
+      // TODO(modernletter) Add some field for audio type to AudioStreamInfo
+      // and set here from audio_type
+    }
+
     pid_state->second->set_config(new_stream_info);
   } else {
     LOG(WARNING) << "Ignoring unsupported stream with pid=" << pes_pid;

packager/media/formats/mp2t/mp2t_media_parser.h

@@ -9,11 +9,13 @@
 #include <deque>
 #include <map>
 #include <memory>
+#include <string>
 
 #include <packager/macros/classes.h>
 #include <packager/media/base/byte_queue.h>
 #include <packager/media/base/media_parser.h>
 #include <packager/media/base/stream_info.h>
+#include <packager/media/formats/mp2t/ts_audio_type.h>
 #include <packager/media/formats/mp2t/ts_stream_type.h>
 
 namespace shaka {
@@ -27,6 +29,12 @@ class PidState;
 class TsPacket;
 class TsSection;
 
+struct PesMetadata {
+  uint32_t max_bitrate;
+  std::string language;
+  TsAudioType audio_type;
+};
+
 class Mp2tMediaParser : public MediaParser {
  public:
   Mp2tMediaParser();
@@ -50,10 +58,15 @@ class Mp2tMediaParser : public MediaParser {
   // Callback invoked to register a PES pid.
   // Possible values for |media_type| are defined in:
   // ISO-13818.1 / ITU H.222 Table 2.34 "Media type assignments".
+  // Possible values for |audio_type| are defined in:
+  // ISO-13818.1 / ITU H.222 Table 2-60 "Audio type values".
   // |pes_pid| is part of the Program Map Table refered by |pmt_pid|.
   void RegisterPes(int pmt_pid,
                    int pes_pid,
                    TsStreamType media_type,
+                   uint32_t max_bitrate,
+                   const std::string& lang,
+                   TsAudioType audio_type,
                    const uint8_t* descriptor,
                    size_t descriptor_length);
 
@@ -94,6 +107,9 @@ class Mp2tMediaParser : public MediaParser {
   // has a deterministic order.
   std::map<int, std::unique_ptr<PidState>> pids_;
 
+  // Map of PIDs and their metadata.
+  std::map<int, PesMetadata> pes_metadata_;
+
   // Whether |init_cb_| has been invoked.
   bool is_initialized_;
 

packager/media/formats/mp2t/mp2t_media_parser_unittest.cc

@@ -12,6 +12,7 @@
 #include <gtest/gtest.h>
 
 #include <packager/macros/logging.h>
+#include <packager/media/base/audio_stream_info.h>
 #include <packager/media/base/media_sample.h>
 #include <packager/media/base/stream_info.h>
 #include <packager/media/base/timestamp.h>
@@ -190,6 +191,19 @@ TEST_F(Mp2tMediaParserTest, PtsZeroDtsWrapAround) {
   EXPECT_GT(video_max_pts_, static_cast<int64_t>(1) << 33);
 }
 
+TEST_F(Mp2tMediaParserTest, PmtEsDescriptors) {
+  //"bear-eng-visualy-impaired-audio.ts" consist of audio stream marked as
+  // english audio with commentary for visualy impaired viewer and max
+  // bitrate set to ~128kbps
+
+  ParseMpeg2TsFile("bear-visualy-impaired-eng-audio.ts", 188);
+  EXPECT_TRUE(parser_->Flush());
+  EXPECT_STREQ("eng", stream_map_[257]->language().c_str());
+
+  auto* audio_info = static_cast<AudioStreamInfo*>(stream_map_[257].get());
+  EXPECT_EQ(131600, audio_info->max_bitrate());
+}
+
 }  // namespace mp2t
 }  // namespace media
 }  // namespace shaka

packager/media/formats/mp2t/ts_audio_type.h

@@ -0,0 +1,30 @@
+// Copyright 2023 Google LLC. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+#ifndef PACKAGER_MEDIA_FORMATS_MP2T_TS_AUDIO_TYPE_H
+#define PACKAGER_MEDIA_FORMATS_MP2T_TS_AUDIO_TYPE_H
+
+#include <stdint.h>
+
+namespace shaka {
+namespace media {
+namespace mp2t {
+
+enum class TsAudioType : uint8_t {
+  // ISO-13818.1 / ITU H.222 Table 2-60 "Audio type values"
+  kUndefined = 0x00,
+  kCleanEffects = 0x01,
+  kHearingImpaired = 0x02,
+  kVisualyImpairedCommentary = 0x03,
+  // 0x04-0x7F - user private
+  // 0x80-0xFF - reserved
+};
+
+}  // namespace mp2t
+}  // namespace media
+}  // namespace shaka
+
+#endif  // PACKAGER_MEDIA_FORMATS_MP2T_TS_AUDIO_TYPE_H

packager/media/formats/mp2t/ts_section_pmt.cc

@@ -10,12 +10,21 @@
 
 #include <packager/media/base/bit_reader.h>
 #include <packager/media/formats/mp2t/mp2t_common.h>
+#include <packager/media/formats/mp2t/ts_audio_type.h>
 #include <packager/media/formats/mp2t/ts_stream_type.h>
 
 namespace shaka {
 namespace media {
 namespace mp2t {
 
+namespace {
+
+const int kISO639LanguageDescriptor = 0x0A;
+const int kMaximumBitrateDescriptor = 0x0E;
+const int kSubtitlingDescriptor = 0x59;
+
+}  // namespace
+
 TsSectionPmt::TsSectionPmt(const RegisterPesCb& register_pes_cb)
     : register_pes_cb_(register_pes_cb) {
 }
@@ -82,6 +91,9 @@ bool TsSectionPmt::ParsePsiSection(BitReader* bit_reader) {
     TsStreamType stream_type;
     const uint8_t* descriptor;
     size_t descriptor_length;
+    std::string lang;
+    uint32_t max_bitrate;
+    TsAudioType audio_type;
   };
   std::vector<Info> pid_info;
   while (static_cast<int>(bit_reader->bits_available()) >
@@ -99,22 +111,59 @@ bool TsSectionPmt::ParsePsiSection(BitReader* bit_reader) {
     // Do not register the PID right away.
     // Wait for the end of the section to be fully parsed
     // to make sure there is no error.
-    pid_info.push_back({pid_es, stream_type, descriptor, es_info_length});
+    pid_info.push_back({pid_es, stream_type, descriptor, es_info_length, "", 0,
+                        TsAudioType::kUndefined});
 
     // Read the ES info descriptors.
     // Defined in section 2.6 of ISO-13818.
-    if (es_info_length > 0) {
+    uint8_t descriptor_tag;
-      uint8_t descriptor_tag;
+    uint8_t descriptor_length;
+
+    while (es_info_length) {
       RCHECK(bit_reader->ReadBits(8, &descriptor_tag));
-      es_info_length--;
+      RCHECK(bit_reader->ReadBits(8, &descriptor_length));
+      es_info_length -= 2;
 
       // See ETSI EN 300 468 Section 6.1
       if (stream_type == TsStreamType::kPesPrivateData &&
-          descriptor_tag == 0x59) {  // subtitling_descriptor
+          descriptor_tag == kSubtitlingDescriptor) {
         pid_info.back().stream_type = TsStreamType::kDvbSubtitles;
+      } else if (descriptor_tag == kISO639LanguageDescriptor &&
+                 descriptor_length >= 4) {
+        // See section 2.6.19 of ISO-13818
+        // Descriptor can contain 0..N language defintions,
+        // we process only the first one
+        RCHECK(es_info_length >= 4);
+
+        char lang[3];
+        RCHECK(bit_reader->ReadBits(8, &lang[0]));  // ISO_639_language_code
+        RCHECK(bit_reader->ReadBits(8, &lang[1]));
+        RCHECK(bit_reader->ReadBits(8, &lang[2]));
+        RCHECK(bit_reader->ReadBits(8, &pid_info.back().audio_type));
+        pid_info.back().lang = std::string(lang, 3);
+
+        es_info_length -= 4;
+        descriptor_length -= 4;
+      } else if (descriptor_tag == kMaximumBitrateDescriptor &&
+                 descriptor_length >= 3) {
+        // See section 2.6.25 of ISO-13818
+        RCHECK(es_info_length >= 3);
+
+        uint32_t max_bitrate;
+        RCHECK(bit_reader->SkipBits(2));  // reserved
+        RCHECK(bit_reader->ReadBits(22, &max_bitrate));
+        // maximum bitrate is stored in units of 50 bytes per second
+        pid_info.back().max_bitrate = 50 * 8 * max_bitrate;
+
+        es_info_length -= 3;
+        descriptor_length -= 3;
       }
+
+      RCHECK(bit_reader->SkipBits(8 * descriptor_length));
+      es_info_length -= descriptor_length;
     }
-    RCHECK(bit_reader->SkipBits(8 * es_info_length));
+
+    RCHECK(bit_reader->SkipBytes(es_info_length));
   }
 
   // Read the CRC.
@@ -123,8 +172,8 @@ bool TsSectionPmt::ParsePsiSection(BitReader* bit_reader) {
 
   // Once the PMT has been proved to be correct, register the PIDs.
   for (auto& info : pid_info) {
-    register_pes_cb_(info.pid_es, info.stream_type, info.descriptor,
+    register_pes_cb_(info.pid_es, info.stream_type, info.max_bitrate, info.lang,
-                     info.descriptor_length);
+                     info.audio_type, info.descriptor, info.descriptor_length);
   }
 
   return true;

packager/media/formats/mp2t/ts_section_pmt.h

@@ -6,8 +6,10 @@
 #define PACKAGER_MEDIA_FORMATS_MP2T_TS_SECTION_PMT_H_
 
 #include <functional>
+#include <string>
 
 #include <packager/macros/classes.h>
+#include <packager/media/formats/mp2t/ts_audio_type.h>
 #include <packager/media/formats/mp2t/ts_section_psi.h>
 #include <packager/media/formats/mp2t/ts_stream_type.h>
 
@@ -17,10 +19,20 @@ namespace mp2t {
 
 class TsSectionPmt : public TsSectionPsi {
  public:
-  // RegisterPesCb::Run(int pes_pid, int stream_type);
+  // RegisterPesCb::Run(int pes_pid, int stream_type, uint32_t max_bitrate,
+  //  const string& lang, TsAudioType audio_type, uint8_t* descriptor,
+  // size_t desriptor_size);
   // Stream type is defined in
   // "Table 2-34 – Stream type assignments" in H.222
-  typedef std::function<void(int, TsStreamType, const uint8_t*, size_t)>
+  // Audio type is defined in
+  // "Table 2-60 - Audio type values" in H.222
+  typedef std::function<void(int,
+                             TsStreamType,
+                             uint32_t,
+                             const std::string&,
+                             TsAudioType,
+                             const uint8_t*,
+                             size_t)>
       RegisterPesCb;
 
   explicit TsSectionPmt(const RegisterPesCb& register_pes_cb);

packager/media/test/data/README

@@ -29,6 +29,12 @@ bear-640x360.ts - AVC + AAC encode, multiplexed into an MPEG2-TS container.
 bear-640x360_ptswraparound.ts - Same as bear-640x360.ts, with a timestamp wrap-around in the middle, created with the below command:
                                 ffmpeg -itsoffset 95442 -i bear-640x360.ts -c:v copy -c:a copy -muxdelay 0 bear-640x360_ptswraparound.ts
 bear-640x360-hevc.ts - HEVC + AAC encode, multiplexed into an MPEG2-TS container.
+bear-eng-visualy-impaired-audio.ts - Audio stream from bear-640x360.ts marked as english with commentary for visually impaired viewer using the below commands:
+  tsp -I file bear-640x360.ts \
+    -P filter --video --negate
+    -P inject --replace --pid 4096 --xml bear-visualy-impaired-eng-audio-pmt.xml \
+    -O file bear-visualy-impaired-eng-audio.ts
+  (xml template can be obtained by command "tsp -I file bear-640x360.ts -P tables --pid 4096 --tid 2 --max 1 --xml pmt.xml -O drop")
 
 // ISO-BMFF streams.
 bear-1280x720.mp4 - AVC + AAC encode, mulitplexed into an ISOBMFF container.

packager/media/test/data/bear-visualy-impaired-eng-audio-pmt.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<tsduck>
+  <PMT version="0" current="true" service_id="0x0001" PCR_PID="0x0100">
+    <metadata PID="4,096"/>
+    <component elementary_PID="0x0101" stream_type="0x0F">
+      <ISO_639_language_descriptor>
+        <language code="eng" audio_type="0x03"/>
+      </ISO_639_language_descriptor>
+      <maximum_bitrate_descriptor maximum_bitrate="131,600"/>
+    </component>
+  </PMT>
+</tsduck>