| // Copyright 2015 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. |
| |
| #ifndef CAST_STREAMING_CONSTANTS_H_ |
| #define CAST_STREAMING_CONSTANTS_H_ |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // NOTE: This file should only contain constants that are reasonably globally |
| // used (i.e., by many modules, and in all or nearly all subdirs). Do NOT add |
| // non-POD constants, functions, interfaces, or any logic to this module. |
| //////////////////////////////////////////////////////////////////////////////// |
| |
| #include <chrono> |
| #include <ratio> |
| |
| namespace openscreen { |
| namespace cast { |
| |
| // Default target playout delay. The playout delay is the window of time between |
| // capture from the source until presentation at the receiver. |
| constexpr std::chrono::milliseconds kDefaultTargetPlayoutDelay(400); |
| |
| // Default UDP port, bound at the Receiver, for Cast Streaming. An |
| // implementation is required to use the port specified by the Receiver in its |
| // ANSWER control message, which may or may not match this port number here. |
| constexpr int kDefaultCastStreamingPort = 2344; |
| |
| // Default TCP port, bound at the TLS server socket level, for Cast Streaming. |
| // An implementation must use the port specified in the DNS-SD published record |
| // for connecting over TLS, which may or may not match this port number here. |
| constexpr int kDefaultCastPort = 8010; |
| |
| // Target number of milliseconds between the sending of RTCP reports. Both |
| // senders and receivers regularly send RTCP reports to their peer. |
| constexpr std::chrono::milliseconds kRtcpReportInterval(500); |
| |
| // This is an important system-wide constant. This limits how much history |
| // the implementation must retain in order to process the acknowledgements of |
| // past frames. |
| // |
| // This value is carefully choosen such that it fits in the 8-bits range for |
| // frame IDs. It is also less than half of the full 8-bits range such that |
| // logic can handle wrap around and compare two frame IDs meaningfully. |
| constexpr int kMaxUnackedFrames = 120; |
| |
| // The network must support a packet size of at least this many bytes. |
| constexpr int kRequiredNetworkPacketSize = 256; |
| |
| // The spec declares RTP timestamps must always have a timebase of 90000 ticks |
| // per second for video. |
| constexpr int kRtpVideoTimebase = 90000; |
| |
| // Minimum resolution is 320x240. |
| constexpr int kMinVideoHeight = 240; |
| constexpr int kMinVideoWidth = 320; |
| |
| // The default frame rate for capture options is 30FPS. |
| constexpr int kDefaultFrameRate = 30; |
| |
| // The default audio sample rate is 48kHz, slightly higher than standard |
| // consumer audio. |
| constexpr int kDefaultAudioSampleRate = 48000; |
| |
| // The default audio number of channels is set to stereo. |
| constexpr int kDefaultAudioChannels = 2; |
| |
| // Codecs known and understood by cast senders and receivers. Note: receivers |
| // are required to implement the following codecs to be Cast V2 compliant: H264, |
| // VP8, AAC, Opus. Senders have to implement at least one codec for audio and |
| // video to start a session. |
| enum class AudioCodec { kAac, kOpus }; |
| enum class VideoCodec { kH264, kVp8, kHevc, kVp9 }; |
| |
| } // namespace cast |
| } // namespace openscreen |
| |
| #endif // CAST_STREAMING_CONSTANTS_H_ |