[AVCCodecHandler] Some code cleanups

Most rilevant change,
add our implementation of ReadGolomb
in order to remove bento4 custom patch

src/codechandler/AVCCodecHandler.cpp

@@ -12,6 +12,28 @@
 
 using namespace UTILS;
 
+namespace
+{
+unsigned int ReadGolomb(AP4_BitReader& bits)
+{
+  unsigned int leading_zeros = 0;
+  while (bits.ReadBit() == 0)
+  {
+    leading_zeros++;
+    if (leading_zeros > 32)
+      return 0; // safeguard
+  }
+  if (leading_zeros)
+  {
+    return (1 << leading_zeros) - 1 + bits.ReadBits(leading_zeros);
+  }
+  else
+  {
+    return 0;
+  }
+}
+} // unnamed namespace
+
 AVCCodecHandler::AVCCodecHandler(AP4_SampleDescription* sd)
   : CodecHandler{sd},
     m_countPictureSetIds{0},
@@ -106,7 +128,8 @@ void AVCCodecHandler::UpdatePPSId(const AP4_DataBuffer& buffer)
   if (!m_needSliceInfo)
     return;
 
-  //Search the Slice header NALU
+  // Iterate data to find all NALU units slice headers of type 5 "Coded slice of an IDR picture"
+  // to get the pic_parameter_set_id value of last NALU
   const AP4_Byte* data(buffer.GetData());
   AP4_Size dataSize(buffer.GetDataSize());
   for (; dataSize;)
@@ -145,25 +168,20 @@ void AVCCodecHandler::UpdatePPSId(const AP4_DataBuffer& buffer)
     if (m_countPictureSetIds < 2)
       m_needSliceInfo = false;
 
-    unsigned int nal_unit_type = *data & 0x1F;
+    unsigned int nalUnitType = *data & 0x1F;
 
-    if (
-        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_OF_NON_IDR_PICTURE ||
-        nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_OF_IDR_PICTURE //||
-        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_DATA_PARTITION_A ||
-        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_DATA_PARTITION_B ||
-        //nal_unit_type == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_DATA_PARTITION_C
-    )
+    // Following code is a simplification of AP4_AvcFrameParser::ParseSliceHeader from AP4_AvcFrameParser::Feed
+    if (nalUnitType == AP4_AVC_NAL_UNIT_TYPE_CODED_SLICE_OF_IDR_PICTURE)
     {
       AP4_DataBuffer unescaped(data, dataSize);
       AP4_NalParser::Unescape(unescaped);
       AP4_BitReader bits(unescaped.GetData(), unescaped.GetDataSize());
 
       bits.SkipBits(8); // NAL Unit Type
 
-      AP4_AvcFrameParser::ReadGolomb(bits); // first_mb_in_slice
-      AP4_AvcFrameParser::ReadGolomb(bits); // slice_type
-      m_pictureId = AP4_AvcFrameParser::ReadGolomb(bits); //picture_set_id
+      ReadGolomb(bits); // first_mb_in_slice
+      ReadGolomb(bits); // slice_type
+      m_pictureId = ReadGolomb(bits); // pic_parameter_set_id
     }
     // move to the next NAL unit
     data += naluSize;

src/codechandler/AVCCodecHandler.h

@@ -1,26 +1,28 @@
-/*
- *  Copyright (C) 2022 Team Kodi
- *  This file is part of Kodi - https://kodi.tv
- *
- *  SPDX-License-Identifier: GPL-2.0-or-later
- *  See LICENSES/README.md for more information.
- */
-
-#pragma once
-
-#include "CodecHandler.h"
-
-class ATTR_DLL_LOCAL AVCCodecHandler : public CodecHandler
-{
-public:
-  AVCCodecHandler(AP4_SampleDescription* sd);
-  bool ExtraDataToAnnexB() override;
-  void UpdatePPSId(const AP4_DataBuffer& buffer) override;
-  bool GetInformation(kodi::addon::InputstreamInfo& info) override;
-  STREAMCODEC_PROFILE GetProfile() override { return m_codecProfile; };
-
-private:
-  unsigned int m_countPictureSetIds;
-  STREAMCODEC_PROFILE m_codecProfile;
-  bool m_needSliceInfo;
-};
+/*
+ *  Copyright (C) 2022 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#pragma once
+
+#include "CodecHandler.h"
+
+class ATTR_DLL_LOCAL AVCCodecHandler : public CodecHandler
+{
+public:
+  AVCCodecHandler(AP4_SampleDescription* sd);
+  bool ExtraDataToAnnexB() override;
+  void UpdatePPSId(const AP4_DataBuffer& buffer) override;
+  bool GetInformation(kodi::addon::InputstreamInfo& info) override;
+  STREAMCODEC_PROFILE GetProfile() override { return m_codecProfile; };
+
+private:
+  unsigned int m_countPictureSetIds;
+  STREAMCODEC_PROFILE m_codecProfile;
+  bool m_needSliceInfo;
+  AP4_UI08 m_pictureId{0};
+  AP4_UI08 m_pictureIdPrev{AP4_AVC_PPS_MAX_ID};
+};

src/codechandler/CodecHandler.h

@@ -20,9 +20,8 @@
 class ATTR_DLL_LOCAL CodecHandler
 {
 public:
-  CodecHandler(AP4_SampleDescription* sd)
-    : m_sampleDescription(sd), m_naluLengthSize(0), m_pictureId(0), m_pictureIdPrev(0xFF){};
-  virtual ~CodecHandler(){};
+  CodecHandler(AP4_SampleDescription* sd) : m_sampleDescription(sd) {}
+  virtual ~CodecHandler() = default;
 
   virtual void UpdatePPSId(const AP4_DataBuffer& buffer) {}
 
@@ -46,9 +45,7 @@ class ATTR_DLL_LOCAL CodecHandler
 
   AP4_SampleDescription* m_sampleDescription;
   AP4_DataBuffer m_extraData;
-  AP4_UI08 m_naluLengthSize;
-  AP4_UI08 m_pictureId;
-  AP4_UI08 m_pictureIdPrev;
+  AP4_UI08 m_naluLengthSize{0};
 
   protected:
   bool UpdateInfoCodecName(kodi::addon::InputstreamInfo& info, const char* codecName);