Fix OBU total length error

2025-10-27 04:35:34 +08:00 · 2024-04-24 17:27:53 +08:00
parent 5deaacab51
commit 76465a95c2
8 changed files with 30 additions and 28 deletions
--- a/src/rtp/obu_parser.cpp
+++ b/src/rtp/obu_parser.cpp
@@ -0,0 +1,109 @@
+#include "obu_parser.h"
+
+#include "byte_buffer.h"
+#include "log.h"
+
+constexpr int kAggregationHeaderSize = 1;
+// when there are 3 or less OBU (fragments) in a packet, size of the last one
+// can be omited.
+constexpr int kMaxNumObusToOmitSize = 3;
+constexpr uint8_t kObuSizePresentBit = 0b0'0000'010;
+constexpr int kObuTypeSequenceHeader = 1;
+constexpr int kObuTypeTemporalDelimiter = 2;
+constexpr int kObuTypeTileList = 8;
+constexpr int kObuTypePadding = 15;
+
+const char* ObuTypeToString(OBU_TYPE type) {
+  switch (type) {
+    case OBU_SEQUENCE_HEADER:
+      return "OBU_SEQUENCE_HEADER";
+    case OBU_TEMPORAL_DELIMITER:
+      return "OBU_TEMPORAL_DELIMITER";
+    case OBU_FRAME_HEADER:
+      return "OBU_FRAME_HEADER";
+    case OBU_REDUNDANT_FRAME_HEADER:
+      return "OBU_REDUNDANT_FRAME_HEADER";
+    case OBU_FRAME:
+      return "OBU_FRAME";
+    case OBU_TILE_GROUP:
+      return "OBU_TILE_GROUP";
+    case OBU_METADATA:
+      return "OBU_METADATA";
+    case OBU_TILE_LIST:
+      return "OBU_TILE_LIST";
+    case OBU_PADDING:
+      return "OBU_PADDING";
+    default:
+      break;
+  }
+  return "<Invalid OBU Type>";
+}
+
+bool ObuHasExtension(uint8_t obu_header) { return obu_header & 0b0'0000'100; }
+
+bool ObuHasSize(uint8_t obu_header) { return obu_header & kObuSizePresentBit; }
+
+int ObuType(uint8_t obu_header) { return (obu_header & 0b0'1111'000) >> 3; }
+
+std::vector<Obu> ParseObus(uint8_t* payload, int payload_size) {
+  std::vector<Obu> result;
+  ByteBufferReader payload_reader(reinterpret_cast<const char*>(payload),
+                                  payload_size);
+  while (payload_reader.Length() > 0) {
+    Obu obu;
+    payload_reader.ReadUInt8(&obu.header_);
+
+    obu.size_ = 1;
+    if (ObuHasExtension(obu.header_)) {
+      if (payload_reader.Length() == 0) {
+        LOG_ERROR(
+            "Malformed AV1 input: expected extension_header, no more bytes in "
+            "the buffer. Offset: {}",
+            (payload_size - payload_reader.Length()));
+        return {};
+      }
+      payload_reader.ReadUInt8(&obu.extension_header_);
+      ++obu.size_;
+    }
+    if (!ObuHasSize(obu.header_)) {
+      obu.SetPayload(reinterpret_cast<const uint8_t*>(payload_reader.Data()),
+                     payload_reader.Length());
+      payload_reader.Consume(payload_reader.Length());
+    } else {
+      uint64_t payload_size = 0;
+      size_t len = 0;
+      if (!payload_reader.ReadUVarint(&payload_size, &len) ||
+          payload_size > payload_reader.Length()) {
+        LOG_ERROR(
+            "Malformed AV1 input: declared payload_size {} is larger than "
+            "remaining "
+            "buffer size {}",
+            payload_size, payload_reader.Length());
+        return {};
+      }
+      obu.SetPayload(reinterpret_cast<const uint8_t*>(payload_reader.Data()),
+                     payload_size);
+      obu.size_ += len;
+      payload_reader.Consume(payload_size);
+    }
+    obu.size_ += obu.payload_size_;
+    // Skip obus that shouldn't be transfered over rtp.
+    int obu_type = ObuType(obu.header_);
+    // if (obu_type != kObuTypeTemporalDelimiter &&  //
+    //     obu_type != kObuTypeTileList &&           //
+    //     obu_type != kObuTypePadding) {
+    //   result.push_back(obu);
+    // }
+    if (1) {
+      result.push_back(obu);
+    }
+  }
+
+  // for (int i = 0; i < result.size(); i++) {
+  //   LOG_ERROR("[{}] Obu size = [{}], Obu type [{}]", i,
+  //   result[i].payload_size_,
+  //             ObuTypeToString((OBU_TYPE)ObuType(result[i].header_)));
+  // }
+
+  return result;
+}