rtp_demuxer.h | Explore in Territory

/*
 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef CALL_RTP_DEMUXER_H_
#define CALL_RTP_DEMUXER_H_

#include <map>
#include <string>
#include <utility>
#include <vector>

#include "absl/strings/string_view.h"
#include "rtc_base/containers/flat_map.h"
#include "rtc_base/containers/flat_set.h"

namespace webrtc {

class RtpPacketReceived;
class RtpPacketSinkInterface;

// This struct describes the criteria that will be used to match packets to a
// specific sink.
class RtpDemuxerCriteria { … };

// This class represents the RTP demuxing, for a single RTP session (i.e., one
// SSRC space, see RFC 7656). It isn't thread aware, leaving responsibility of
// multithreading issues to the user of this class.
// The demuxing algorithm follows the sketch given in the BUNDLE draft:
// https://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-38#section-10.2
// with modifications to support RTP stream IDs also.
//
// When a packet is received, the RtpDemuxer will route according to the
// following rules:
// 1. If the packet contains the MID header extension, and no sink has been
//    added with that MID as a criteria, the packet is not routed.
// 2. If the packet has the MID header extension, but no RSID or RRID extension,
//    and the MID is bound to a sink, then bind its SSRC to the same sink and
//    forward the packet to that sink. Note that rebinding to the same sink is
//    not an error. (Later packets with that SSRC would therefore be forwarded
//    to the same sink, whether they have the MID header extension or not.)
// 3. If the packet has the MID header extension and either the RSID or RRID
//    extension, and the MID, RSID (or RRID) pair is bound to a sink, then bind
//    its SSRC to the same sink and forward the packet to that sink. Later
//    packets with that SSRC will be forwarded to the same sink.
// 4. If the packet has the RSID or RRID header extension, but no MID extension,
//    and the RSID or RRID is bound to an RSID sink, then bind its SSRC to the
//    same sink and forward the packet to that sink. Later packets with that
//    SSRC will be forwarded to the same sink.
// 5. If the packet's SSRC is bound to an SSRC through a previous call to
//    AddSink, then forward the packet to that sink. Note that the RtpDemuxer
//    will not verify the payload type even if included in the sink's criteria.
//    The sink is expected to do the check in its handler.
// 6. If the packet's payload type is bound to exactly one payload type sink
//    through an earlier call to AddSink, then forward the packet to that sink.
// 7. Otherwise, the packet is not routed.
//
// In summary, the routing algorithm will always try to first match MID and RSID
// (including through SSRC binding), match SSRC directly as needed, and use
// payload types only if all else fails.
class RtpDemuxer { … };

}  // namespace webrtc

#endif  // CALL_RTP_DEMUXER_H_
chromium/third_party/webrtc/call/rtp_demuxer.h
