1 files changed, 53 insertions, 0 deletions
diff --git a/third_party/libwebrtc/common_video/h265/h265_vps_parser.cc b/third_party/libwebrtc/common_video/h265/h265_vps_parser.cc
new file mode 100644
index 0000000000..16b967dad4
--- /dev/null
+++ b/third_party/libwebrtc/common_video/h265/h265_vps_parser.cc
@@ -0,0 +1,53 @@
+/*
+ *  Copyright (c) 2023 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "common_video/h265/h265_vps_parser.h"
+
+#include "common_video/h265/h265_common.h"
+#include "rtc_base/bit_buffer.h"
+#include "rtc_base/bitstream_reader.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+H265VpsParser::VpsState::VpsState() = default;
+
+// General note: this is based off the 08/2021 version of the H.265 standard.
+// You can find it on this page:
+// http://www.itu.int/rec/T-REC-H.265
+
+// Unpack RBSP and parse VPS state from the supplied buffer.
+absl::optional<H265VpsParser::VpsState> H265VpsParser::ParseVps(
+    const uint8_t* data,
+    size_t length) {
+  RTC_DCHECK(data);
+  return ParseInternal(H265::ParseRbsp(data, length));
+}
+
+absl::optional<H265VpsParser::VpsState> H265VpsParser::ParseInternal(
+    rtc::ArrayView<const uint8_t> buffer) {
+  BitstreamReader reader(buffer);
+
+  // Now, we need to use a bit buffer to parse through the actual H265 VPS
+  // format. See Section 7.3.2.1 ("Video parameter set RBSP syntax") of the
+  // H.265 standard for a complete description.
+  VpsState vps;
+
+  // vps_video_parameter_set_id: u(4)
+  vps.id = reader.ReadBits(4);
+
+  if (!reader.Ok()) {
+    return absl::nullopt;
+  }
+
+  return vps;
+}
+
+}  // namespace webrtc