Packetizer/Depacketizer for RTP.

remoting/protocol/rtp_video_writer.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/protocol/rtp_video_writer.h"
 
 #include "net/base/io_buffer.h"
 #include "remoting/base/compound_buffer.h"
 #include "remoting/proto/video.pb.h"
 #include "remoting/protocol/rtp_writer.h"
 #include "remoting/protocol/session.h"
 
 namespace remoting {
 namespace protocol {
 
+namespace {
+const int kMtu = 1200;
+}  // namespace
+
 RtpVideoWriter::RtpVideoWriter() { }
 
 RtpVideoWriter::~RtpVideoWriter() { }
 
 void RtpVideoWriter::Init(protocol::Session* session) {
   rtp_writer_.Init(session->video_rtp_channel(), session->video_rtcp_channel());
 }
 
 void RtpVideoWriter::SendPacket(const VideoPacket& packet) {
+  CHECK(packet.format().encoding() == VideoPacketFormat::ENCODING_VP8)
+      << "Only VP8 is supported in RTP.";
+
   CompoundBuffer payload;
+  // TODO(sergeyu): This copy would not be necessary CompoundBuffer was used
+  // inside of VideoPacket.
   payload.AppendCopyOf(packet.data().data(), packet.data().size());
 
-  rtp_writer_.SendPacket(payload, packet.timestamp());
+  Vp8Descriptor vp8_desriptor;
+  // TODO(sergeyu): Add a flag in VideoPacket that indicates whether this is a
+  // key frame or not.
+  vp8_desriptor.non_reference_frame = false;
+  vp8_desriptor.picture_id = kuint32max;
+
+  int position = 0;
+  while (position < payload.total_bytes()) {
+    int size = std::min(kMtu, payload.total_bytes() - position);
+
+    // Frame beginning flag is set only for the first packet in the first
+    // partition.
+    vp8_desriptor.frame_beginning =
+        (packet.flags() & VideoPacket::FIRST_PACKET) != 0 && position == 0;
+
+    // Marker bit is set only for the last packet in the last partition.
+    bool marker = (position + size) == payload.total_bytes() &&
+        (packet.flags() & VideoPacket::LAST_PACKET) != 0;
+
+    // Set fragmentation flag appropriately.
+    if (position == 0) {
+      if (size == payload.total_bytes()) {
+        vp8_desriptor.fragmentation_info = Vp8Descriptor::NOT_FRAGMENTED;
+      } else {
+        vp8_desriptor.fragmentation_info = Vp8Descriptor::FIRST_FRAGMENT;
+      }
+    } else {
+      if (position + size == payload.total_bytes()) {
+        vp8_desriptor.fragmentation_info = Vp8Descriptor::LAST_FRAGMENT;
+      } else {
+        vp8_desriptor.fragmentation_info = Vp8Descriptor::MIDDLE_FRAGMENT;
+      }
+    }
+
+    // Create CompoundBuffer for the chunk.
+    CompoundBuffer chunk;
+    chunk.CopyFrom(payload, position, position + size);
+
+    // And send it.
+    rtp_writer_.SendPacket(packet.timestamp(), marker, vp8_desriptor, chunk);
+
+    position += size;
+  }
+
+  DCHECK_EQ(position, payload.total_bytes());
 }
 
 int RtpVideoWriter::GetPendingPackets() {
   return rtp_writer_.GetPendingPackets();
 }
 
-
 void RtpVideoWriter::Close() {
   rtp_writer_.Close();
 }
 
 }  // namespace protocol
 }  // namespace remoting