| // Copyright 2019 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_SSRC_H_ |
| #define CAST_STREAMING_SSRC_H_ |
| |
| #include <stdint.h> |
| |
| namespace openscreen { |
| namespace cast { |
| |
| // A Synchronization Source is a 32-bit opaque identifier used in RTP packets |
| // for identifying the source (or recipient) of a logical sequence of encoded |
| // audio/video frames. In other words, an audio stream will have one sender SSRC |
| // and a video stream will have a different sender SSRC. |
| using Ssrc = uint32_t; |
| |
| // The "not set" or "null" value for the Ssrc type. |
| constexpr Ssrc kNullSsrc{0}; |
| |
| // Computes a new SSRC that will be used to uniquely identify an RTP stream. The |
| // |higher_priority| argument, if true, will generate an SSRC that causes the |
| // system to use a higher priority when scheduling data transmission. Generally, |
| // this is set to true for audio streams and false for video streams. |
| Ssrc GenerateSsrc(bool higher_priority); |
| |
| // Returns a value indicating how to prioritize data transmission for a stream |
| // with |ssrc_a| versus a stream with |ssrc_b|: |
| // |
| // ret < 0: Stream |ssrc_a| has higher priority. |
| // ret == 0: Equal priority. |
| // ret > 0: Stream |ssrc_b| has higher priority. |
| int ComparePriority(Ssrc ssrc_a, Ssrc ssrc_b); |
| |
| } // namespace cast |
| } // namespace openscreen |
| |
| #endif // CAST_STREAMING_SSRC_H_ |