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Diffstat (limited to 'chromium/media/cast/receiver/frame_receiver.h')
-rw-r--r-- | chromium/media/cast/receiver/frame_receiver.h | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/chromium/media/cast/receiver/frame_receiver.h b/chromium/media/cast/receiver/frame_receiver.h new file mode 100644 index 00000000000..ac14ab1e0fb --- /dev/null +++ b/chromium/media/cast/receiver/frame_receiver.h @@ -0,0 +1,184 @@ +// Copyright 2014 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 MEDIA_CAST_RECEIVER_FRAME_RECEIVER_H_ +#define MEDIA_CAST_RECEIVER_FRAME_RECEIVER_H_ + +#include "base/memory/ref_counted.h" +#include "base/memory/scoped_ptr.h" +#include "base/memory/weak_ptr.h" +#include "base/time/time.h" +#include "media/cast/base/clock_drift_smoother.h" +#include "media/cast/cast_config.h" +#include "media/cast/cast_receiver.h" +#include "media/cast/framer/framer.h" +#include "media/cast/logging/logging_defines.h" +#include "media/cast/rtcp/receiver_rtcp_event_subscriber.h" +#include "media/cast/rtcp/rtcp.h" +#include "media/cast/rtp_receiver/receiver_stats.h" +#include "media/cast/rtp_receiver/rtp_parser/rtp_parser.h" +#include "media/cast/rtp_receiver/rtp_receiver_defines.h" +#include "media/cast/transport/utility/transport_encryption_handler.h" + +namespace media { +namespace cast { + +class CastEnvironment; + +// FrameReceiver receives packets out-of-order while clients make requests for +// complete frames in-order. (A frame consists of one or more packets.) +// +// FrameReceiver also includes logic for computing the playout time for each +// frame, accounting for a constant targeted playout delay. The purpose of the +// playout delay is to provide a fixed window of time between the capture event +// on the sender and the playout on the receiver. This is important because +// each step of the pipeline (i.e., encode frame, then transmit/retransmit from +// the sender, then receive and re-order packets on the receiver, then decode +// frame) can vary in duration and is typically very hard to predict. +// +// Each request for a frame includes a callback which FrameReceiver guarantees +// will be called at some point in the future unless the FrameReceiver is +// destroyed. Clients should generally limit the number of outstanding requests +// (perhaps to just one or two). +// +// This class is not thread safe. Should only be called from the Main cast +// thread. +class FrameReceiver : public RtpPayloadFeedback, + public base::SupportsWeakPtr<FrameReceiver> { + public: + FrameReceiver(const scoped_refptr<CastEnvironment>& cast_environment, + const FrameReceiverConfig& config, + EventMediaType event_media_type, + transport::PacedPacketSender* const packet_sender); + + virtual ~FrameReceiver(); + + // Request an encoded frame. + // + // The given |callback| is guaranteed to be run at some point in the future, + // except for those requests still enqueued at destruction time. + void RequestEncodedFrame(const ReceiveEncodedFrameCallback& callback); + + // Called to deliver another packet, possibly a duplicate, and possibly + // out-of-order. Returns true if the parsing of the packet succeeded. + bool ProcessPacket(scoped_ptr<Packet> packet); + + // TODO(miu): This is the wrong place for this, but the (de)serialization + // implementation needs to be consolidated first. + static bool ParseSenderSsrc(const uint8* packet, size_t length, uint32* ssrc); + + protected: + friend class FrameReceiverTest; // Invokes ProcessParsedPacket(). + + void ProcessParsedPacket(const RtpCastHeader& rtp_header, + const uint8* payload_data, + size_t payload_size); + + // RtpPayloadFeedback implementation. + virtual void CastFeedback(const RtcpCastMessage& cast_message) OVERRIDE; + + private: + // Processes ready-to-consume packets from |framer_|, decrypting each packet's + // payload data, and then running the enqueued callbacks in order (one for + // each packet). This method may post a delayed task to re-invoke itself in + // the future to wait for missing/incomplete frames. + void EmitAvailableEncodedFrames(); + + // Clears the |is_waiting_for_consecutive_frame_| flag and invokes + // EmitAvailableEncodedFrames(). + void EmitAvailableEncodedFramesAfterWaiting(); + + // Computes the playout time for a frame with the given |rtp_timestamp|. + // Because lip-sync info is refreshed regularly, calling this method with the + // same argument may return different results. + base::TimeTicks GetPlayoutTime(uint32 rtp_timestamp) const; + + // Schedule timing for the next cast message. + void ScheduleNextCastMessage(); + + // Schedule timing for the next RTCP report. + void ScheduleNextRtcpReport(); + + // Actually send the next cast message. + void SendNextCastMessage(); + + // Actually send the next RTCP report. + void SendNextRtcpReport(); + + const scoped_refptr<CastEnvironment> cast_environment_; + + // Deserializes a packet into a RtpHeader + payload bytes. + RtpParser packet_parser_; + + // Accumulates packet statistics, including packet loss, counts, and jitter. + ReceiverStats stats_; + + // Partitions logged events by the type of media passing through. + EventMediaType event_media_type_; + + // Subscribes to raw events. + // Processes raw events to be sent over to the cast sender via RTCP. + ReceiverRtcpEventSubscriber event_subscriber_; + + // RTP timebase: The number of RTP units advanced per one second. + const int rtp_timebase_; + + // The total amount of time between a frame's capture/recording on the sender + // and its playback on the receiver (i.e., shown to a user). This is fixed as + // a value large enough to give the system sufficient time to encode, + // transmit/retransmit, receive, decode, and render; given its run-time + // environment (sender/receiver hardware performance, network conditions, + // etc.). + const base::TimeDelta target_playout_delay_; + + // Hack: This is used in logic that determines whether to skip frames. + // TODO(miu): Revisit this. Logic needs to also account for expected decode + // time. + const base::TimeDelta expected_frame_duration_; + + // Set to false initially, then set to true after scheduling the periodic + // sending of reports back to the sender. Reports are first scheduled just + // after receiving a first packet (since the first packet identifies the + // sender for the remainder of the session). + bool reports_are_scheduled_; + + // Assembles packets into frames, providing this receiver with complete, + // decodable EncodedFrames. + Framer framer_; + + // Manages sending/receiving of RTCP packets, including sender/receiver + // reports. + Rtcp rtcp_; + + // Decrypts encrypted frames. + transport::TransportEncryptionHandler decryptor_; + + // Outstanding callbacks to run to deliver on client requests for frames. + std::list<ReceiveEncodedFrameCallback> frame_request_queue_; + + // True while there's an outstanding task to re-invoke + // EmitAvailableEncodedFrames(). + bool is_waiting_for_consecutive_frame_; + + // This mapping allows us to log FRAME_ACK_SENT as a frame event. In addition + // it allows the event to be transmitted via RTCP. + RtpTimestamp frame_id_to_rtp_timestamp_[256]; + + // Lip-sync values used to compute the playout time of each frame from its RTP + // timestamp. These are updated each time the first packet of a frame is + // received. + RtpTimestamp lip_sync_rtp_timestamp_; + base::TimeTicks lip_sync_reference_time_; + ClockDriftSmoother lip_sync_drift_; + + // NOTE: Weak pointers must be invalidated before all other member variables. + base::WeakPtrFactory<FrameReceiver> weak_factory_; + + DISALLOW_COPY_AND_ASSIGN(FrameReceiver); +}; + +} // namespace cast +} // namespace media + +#endif // MEDIA_CAST_RECEIVER_FRAME_RECEIVER_H_ |