[HLSTree] Improved GetAudioCodec easier to maintain

src/parser/HLSTree.cpp

@@ -101,35 +101,21 @@ ContainerType DetectContainerTypeFromExt(std::string_view extension)
     return ContainerType::INVALID;
 }
 
-// \brief Workaround to get audio codec from CODECS attribute list
+// \brief Get the first audio codec string from CODECS attribute list
 std::string GetAudioCodec(std::string_view codecs)
 {
-  //! @todo: this way to get the audio codec is inappropriate and can lead to bad playback
-  //! this because CODECS attribute its optionals and not guarantee to provide full codec list
-  //! the codec format should be provided by MP4 demuxer
-
-  // The codec search must follow exactly the following order, this is currently the best workaround
-  // to make multi-channel audio formats work, but since CODECS attribute is unreliable
-  // this workaround can still cause playback problems
-  if (codecs.find(CODEC::FOURCC_EC_3) != std::string::npos)
-    return CODEC::FOURCC_EC_3;
-  else if (codecs.find(CODEC::FOURCC_AC_3) != std::string::npos)
-    return CODEC::FOURCC_AC_3;
-  else
-    return CODEC::FOURCC_MP4A;
-}
-// \brief Workaround to get audio codec from representation codecs list
-std::string GetAudioCodec(const PLAYLIST::CRepresentation* repr)
-{
-  const auto& codecs = repr->GetCodecs();
-  if (CODEC::Contains(codecs, CODEC::FOURCC_EC_3))
-    return CODEC::FOURCC_EC_3;
-  else if (CODEC::Contains(codecs, CODEC::FOURCC_AC_3))
-    return CODEC::FOURCC_AC_3;
-  else
-    return CODEC::FOURCC_MP4A;
+  // Some manifests can provide CODECS attribute with more audio codecs
+  // it seems that usually the first in order of apparence is the one referring to the specified
+  // AUDIO group attribute, so we return the first one found
+  // e.g. CODECS="dvh1.05.01,ec-3,mp4a.40.2", ..., AUDIO="eac-3"
+  const std::vector<std::string> list = STRING::SplitToVec(codecs, ',');
+  for (const std::string& codecStr : list)
+  {
+    if (CODEC::IsAudio(codecStr))
+      return codecStr;
+  }
+  return codecs.data();
 }
-
 } // unnamed namespace
 
 adaptive::CHLSTree::CHLSTree(const CHLSTree& left) : AdaptiveTree(left)
@@ -1019,15 +1005,15 @@ bool adaptive::CHLSTree::ParseManifest(const std::string& data)
     repr->SetTimescale(1000000);
 
     // Try to get the codecs from first representation
-    std::string codec = CODEC::FOURCC_MP4A;
+    std::set<std::string> codecs{CODEC::FOURCC_MP4A};
     auto& adpSets = period->GetAdaptationSets();
     if (!adpSets.empty())
     {
       auto& reprs = adpSets[0]->GetRepresentations();
       if (!reprs.empty())
-        codec = GetAudioCodec(reprs[0].get());
+        codecs = reprs[0]->GetCodecs();
     }
-    repr->AddCodecs(codec);
+    repr->AddCodecs(codecs);
     repr->SetAudioChannels(2);
     repr->SetIsIncludedStream(true);
 

src/utils/Utils.cpp

@@ -385,3 +385,18 @@ std::string UTILS::CODEC::GetVideoDesc(const std::set<std::string>& list)
   }
   return "";
 }
+
+bool UTILS::CODEC::IsAudio(std::string_view codec)
+{
+  for (const auto fourcc : CODEC::AUDIO_FOURCC_LIST)
+  {
+    if (STRING::Contains(codec, fourcc))
+      return true;
+  }
+  for (const auto name : CODEC::AUDIO_NAME_LIST)
+  {
+    if (STRING::Contains(codec, name))
+      return true;
+  }
+  return false;
+}

src/utils/Utils.h

@@ -8,6 +8,7 @@
 
 #pragma once
 
+#include <array>
 #include <cstdint>
 #include <ctime> // time
 #include <map>
@@ -62,6 +63,9 @@ constexpr char* NAME_EAC3 = "eac3"; // Enhanced AC-3
 constexpr char* NAME_OPUS = "opus";
 constexpr char* NAME_VORBIS = "vorbis";
 
+constexpr std::array AUDIO_NAME_LIST = {NAME_AAC,  NAME_DTS,  NAME_AC3,
+                                        NAME_EAC3, NAME_OPUS, NAME_VORBIS};
+
 // Subtitles definitions
 
 constexpr char* NAME_SRT = "srt";
@@ -97,6 +101,11 @@ constexpr char* FOURCC_VORB3 = "vor3"; // Vorbis 3
 constexpr char* FOURCC_VORB3P = "vo3+"; // Vorbis 3+
 constexpr char* FOURCC_DTS_ = "dts"; // Generic prefix for all dts* fourcc, e.g. dtsx
 
+constexpr std::array AUDIO_FOURCC_LIST = {FOURCC_MP4A, FOURCC_AAC_, FOURCC_AACL,
+                                          FOURCC_AC_3, FOURCC_EC_3, FOURCC_OPUS, FOURCC_VORB, FOURCC_VORB1,
+                                          FOURCC_VORB1P, FOURCC_VORB2, FOURCC_VORB2P, FOURCC_VORB3,
+                                          FOURCC_VORB3P, FOURCC_DTS_};
+
 // Fourcc subtitles definitions
 
 constexpr char* FOURCC_WVTT = "wvtt"; // WebVTT
@@ -150,6 +159,13 @@ bool Contains(const std::set<std::string>& list, std::string_view codec, std::st
  */
 std::string GetVideoDesc(const std::set<std::string>& list);
 
+/*!
+ * \brief Determines if the codec string is of type audio, regardless of whether it is a name or fourcc.
+ * \param codec The codec string
+ * \return True if it is audio type, otherwise false
+ */
+bool IsAudio(std::string_view codec);
+
 }
 
 } // namespace UTILS