Utils: Add HEVC SEI parser

5 files changed, 184 insertions, 0 deletions

diff --git a/xbmc/utils/BitstreamReader.cpp b/xbmc/utils/BitstreamReader.cpp
index 8900a40a15..1ec8a11057 100644
--- a/xbmc/utils/BitstreamReader.cpp
+++ b/xbmc/utils/BitstreamReader.cpp
@@ -21,6 +21,8 @@ uint32_t CBitstreamReader::ReadBits(int nbits)
   buffer += offbits / 8;
   offbits %= 8;
 
+  m_posBits += nbits;
+
   return ret;
 }
 
@@ -30,6 +32,8 @@ void CBitstreamReader::SkipBits(int nbits)
   buffer += offbits / 8;
   offbits %= 8;
 
+  m_posBits += nbits;
+
   if (buffer > (start + length))
     oflow = 1;
 }
diff --git a/xbmc/utils/BitstreamReader.h b/xbmc/utils/BitstreamReader.h
index 5d818d3767..8ff803b8b4 100644
--- a/xbmc/utils/BitstreamReader.h
+++ b/xbmc/utils/BitstreamReader.h
@@ -17,10 +17,13 @@ public:
   uint32_t   ReadBits(int nbits);
   void       SkipBits(int nbits);
   uint32_t   GetBits(int nbits);
+  unsigned int Position() { return m_posBits; }
+  unsigned int AvailableBits() { return length * 8 - m_posBits; }
 
 private:
   const uint8_t *buffer, *start;
   int offbits = 0, length, oflow = 0;
+  int m_posBits{0};
 };
 
 const uint8_t* find_start_code(const uint8_t *p, const uint8_t *end, uint32_t *state);
diff --git a/xbmc/utils/CMakeLists.txt b/xbmc/utils/CMakeLists.txt
index 68c5c666af..87429d34c3 100644
--- a/xbmc/utils/CMakeLists.txt
+++ b/xbmc/utils/CMakeLists.txt
@@ -29,6 +29,7 @@ set(SOURCES ActorProtocol.cpp
             FontUtils.cpp
             GpuInfo.cpp
             GroupUtils.cpp
+            HevcSei.cpp
             HTMLUtil.cpp
             HttpHeader.cpp
             HttpParser.cpp
@@ -115,6 +116,7 @@ set(HEADERS ActorProtocol.h
             GpuInfo.h
             GroupUtils.h
             HDRCapabilities.h
+            HevcSei.h
             HTMLUtil.h
             HttpHeader.h
             HttpParser.h
diff --git a/xbmc/utils/HevcSei.cpp b/xbmc/utils/HevcSei.cpp
new file mode 100644
index 0000000000..03cfc14916
--- /dev/null
+++ b/xbmc/utils/HevcSei.cpp
@@ -0,0 +1,122 @@
+/*
+ *  Copyright (C) 2024 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.
+ */
+
+#include "HevcSei.h"
+
+void HevcAddStartCodeEmulationPrevention3Byte(std::vector<uint8_t>& buf)
+{
+  size_t i = 0;
+
+  while (i < buf.size())
+  {
+    if (i > 2 && buf[i - 2] == 0 && buf[i - 1] == 0 && buf[i] <= 3)
+      buf.insert(buf.begin() + i, 3);
+
+    i += 1;
+  }
+}
+
+void HevcClearStartCodeEmulationPrevention3Byte(const uint8_t* buf,
+                                                const size_t len,
+                                                std::vector<uint8_t>& out)
+{
+  size_t i = 0;
+
+  if (len > 2)
+  {
+    out.reserve(len);
+
+    out.emplace_back(buf[0]);
+    out.emplace_back(buf[1]);
+
+    for (i = 2; i < len; i++)
+    {
+      if (!(buf[i - 2] == 0 && buf[i - 1] == 0 && buf[i] == 3))
+        out.emplace_back(buf[i]);
+    }
+  }
+  else
+  {
+    out.assign(buf, buf + len);
+  }
+}
+
+int CHevcSei::ParseSeiMessage(CBitstreamReader& br, std::vector<CHevcSei>& messages)
+{
+  CHevcSei sei;
+  uint8_t lastPayloadTypeByte{0};
+  uint8_t lastPayloadSizeByte{0};
+
+  sei.m_msgOffset = br.Position() / 8;
+
+  lastPayloadTypeByte = br.ReadBits(8);
+  while (lastPayloadTypeByte == 0xFF)
+  {
+    lastPayloadTypeByte = br.ReadBits(8);
+    sei.m_payloadType += 255;
+  }
+
+  sei.m_payloadType += lastPayloadTypeByte;
+
+  lastPayloadSizeByte = br.ReadBits(8);
+  while (lastPayloadSizeByte == 0xFF)
+  {
+    lastPayloadSizeByte = br.ReadBits(8);
+    sei.m_payloadSize += 255;
+  }
+
+  sei.m_payloadSize += lastPayloadSizeByte;
+  sei.m_payloadOffset = br.Position() / 8;
+
+  // Invalid size
+  if (sei.m_payloadSize > br.AvailableBits())
+    return 1;
+
+  br.SkipBits(sei.m_payloadSize * 8);
+  messages.emplace_back(sei);
+
+  return 0;
+}
+
+std::vector<CHevcSei> CHevcSei::ParseSeiRbspInternal(const uint8_t* buf, const size_t len)
+{
+  std::vector<CHevcSei> messages;
+
+  if (len > 4)
+  {
+    CBitstreamReader br(buf, len);
+
+    // forbidden_zero_bit, nal_type, nuh_layer_id, temporal_id
+    // nal_type == SEI_PREFIX should already be verified by caller
+    br.SkipBits(16);
+
+    while (true)
+    {
+      if (ParseSeiMessage(br, messages))
+        break;
+
+      if (br.AvailableBits() <= 8)
+        break;
+    }
+  }
+
+  return messages;
+}
+
+std::vector<CHevcSei> CHevcSei::ParseSeiRbsp(const uint8_t* buf, const size_t len)
+{
+  return ParseSeiRbspInternal(buf, len);
+}
+
+std::vector<CHevcSei> CHevcSei::ParseSeiRbspUnclearedEmulation(const uint8_t* inData,
+                                                               const size_t inDataLen,
+                                                               std::vector<uint8_t>& buf)
+{
+  HevcClearStartCodeEmulationPrevention3Byte(inData, inDataLen, buf);
+  return ParseSeiRbsp(buf.data(), buf.size());
+}
diff --git a/xbmc/utils/HevcSei.h b/xbmc/utils/HevcSei.h
new file mode 100644
index 0000000000..08943afd54
--- /dev/null
+++ b/xbmc/utils/HevcSei.h
@@ -0,0 +1,53 @@
+/*
+ *  Copyright (C) 2024 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 "BitstreamReader.h"
+
+#include <optional>
+#include <vector>
+
+/*!
+ * \brief Parses HEVC SEI messages for supplemental video information.
+ *
+ * The CHevcSei class is used to interpret and handle Supplemental Enhancement
+ * Information (SEI) messages found in High Efficiency Video Coding (HEVC)
+ * bitstreams. It is particularly useful for extracting HDR10+ metadata and
+ * other types of supplemental data from HEVC encoded video streams.
+ *
+ * \note This class deals with SEI messages in HEVC streams and does not
+ * process the video content itself.
+ */
+class CHevcSei
+{
+public:
+  CHevcSei() = default;
+  ~CHevcSei() = default;
+
+  uint8_t m_payloadType{0};
+  size_t m_payloadSize{0};
+
+  // In relation to the input SEI rbsp payload
+  size_t m_msgOffset{0};
+  size_t m_payloadOffset{0};
+
+  // Parses SEI payload assumed to not have emulation prevention 3 bytes
+  static std::vector<CHevcSei> ParseSeiRbsp(const uint8_t* buf, const size_t len);
+
+  // Clears emulation prevention 3 bytes and fills in the passed buf
+  static std::vector<CHevcSei> ParseSeiRbspUnclearedEmulation(const uint8_t* inData,
+                                                              const size_t inDataLen,
+                                                              std::vector<uint8_t>& buf);
+
+private:
+  // Parses single SEI message from the reader and pushes it to the list
+  static int ParseSeiMessage(CBitstreamReader& br, std::vector<CHevcSei>& messages);
+
+  static std::vector<CHevcSei> ParseSeiRbspInternal(const uint8_t* buf, const size_t len);
+};