remoting/proto/video.proto

// Copyright (c) 2012 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.

// Protocol for video messages.

syntax = "proto2";

option optimize_for = LITE_RUNTIME;

package remoting;

message VideoPacketFormat {
  // Identifies how the image was encoded.
  enum Encoding {
    ENCODING_INVALID = -1;
    ENCODING_VERBATIM = 0;
    ENCODING_ZLIB = 1;
    ENCODING_VP8 = 2;
  };

  // X,Y coordinates (in screen pixels) for origin of this update.
  optional int32 x = 1;
  optional int32 y = 2;

  // Width, height (in screen pixels) for this update.
  optional int32 width = 3;
  optional int32 height = 4;

  // The encoding used for this image update.
  optional Encoding encoding = 5 [default = ENCODING_INVALID];
  
  // Width and height of the whole screen.
  optional int32 screen_width = 6;
  optional int32 screen_height = 7;

  // Horizontal and vertical DPI of the screen. If either of these is zero or
  // unset, the corresponding DPI should be assumed to be 96 (Windows' default)
  optional int32 x_dpi = 8;
  optional int32 y_dpi = 9;
}

// TODO(hclam): Remove this message once we can obtain dirty rects from libvpx.
message Rect {
  optional int32 x = 1;
  optional int32 y = 2;
  optional int32 width = 3;
  optional int32 height = 4;
}

message VideoPacket {
  // Bitmasks for use in the flags field below.
  //
  // The encoder may fragment one update into multiple partitions.
  // Each partition may be divided into multiple packets depending on
  // how the encoder outputs data. Thus, one update can logically
  // consist of multiple packets. The FIRST_PACKET and LAST_PACKET
  // flags are used to indicate the start and end of a partition. The
  // LAST_PARTITION flag is set for the last packet in the last
  // partition. Here are notable consequences:
  //  * Both FIRST_PACKET and LAST_PACKET may be set if an update is only
  //    one packet long.
  //  * The VideoPacketFormat is only supplied in a FIRST_PACKET.
  //  * LAST_PARTITION can be set only in packet that has LAST_PACKET set.
  //  * An local update cannot change format between a FIRST_PACKET and
  //    a LAST_PACKET.
  //  * All packets in one logical update must be processed in order, and
  //    packets may not be skipped.
  enum Flags {
    FIRST_PACKET = 1;
    LAST_PACKET = 2;
    LAST_PARTITION = 4;
  }
  optional int32 flags = 1 [default = 0];

  // The sequence number of the partial data for updating a rectangle.
  optional int32 sequence_number = 2 [default = 0];

  optional int32 timestamp = 3 [default = 0];

  // This is provided on the first packet of the rectangle data, when
  // the flags has FIRST_PACKET set.
  optional VideoPacketFormat format = 4;

  optional bytes data = 5;

  // This field is only for VP8 to provide out-of-band information of dirty
  // rects.
  // TODO(hclam): Remove this field when we can obtain this information from
  // libvpx.
  repeated Rect dirty_rects = 6;

  // Time in milliseconds spent in capturing this video frame.
  optional int32 capture_time_ms = 7;

  // Time in milliseconds spent in encoding this video frame.
  optional int32 encode_time_ms = 8;

  // The most recent sequence number received from the client on the event
  // channel.
  optional int64 client_sequence_number = 9;
}