2 * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
11 #ifndef WEBRTC_MODULES_VIDEO_CODING_MAIN_SOURCE_JITTER_BUFFER_H_
12 #define WEBRTC_MODULES_VIDEO_CODING_MAIN_SOURCE_JITTER_BUFFER_H_
19 #include "webrtc/modules/interface/module_common_types.h"
20 #include "webrtc/modules/video_coding/main/interface/video_coding.h"
21 #include "webrtc/modules/video_coding/main/interface/video_coding_defines.h"
22 #include "webrtc/modules/video_coding/main/source/decoding_state.h"
23 #include "webrtc/modules/video_coding/main/source/inter_frame_delay.h"
24 #include "webrtc/modules/video_coding/main/source/jitter_buffer_common.h"
25 #include "webrtc/modules/video_coding/main/source/jitter_estimator.h"
26 #include "webrtc/system_wrappers/interface/constructor_magic.h"
27 #include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
28 #include "webrtc/typedefs.h"
37 // forward declarations
43 class VCMEncodedFrame;
45 typedef std::list<VCMFrameBuffer*> UnorderedFrameList;
47 struct VCMJitterSample {
48 VCMJitterSample() : timestamp(0), frame_size(0), latest_packet_time(-1) {}
51 int64_t latest_packet_time;
54 class TimestampLessThan {
56 bool operator() (const uint32_t& timestamp1,
57 const uint32_t& timestamp2) const {
58 return IsNewerTimestamp(timestamp2, timestamp1);
63 : public std::map<uint32_t, VCMFrameBuffer*, TimestampLessThan> {
65 void InsertFrame(VCMFrameBuffer* frame);
66 VCMFrameBuffer* FindFrame(uint32_t timestamp) const;
67 VCMFrameBuffer* PopFrame(uint32_t timestamp);
68 VCMFrameBuffer* Front() const;
69 VCMFrameBuffer* Back() const;
70 int RecycleFramesUntilKeyFrame(FrameList::iterator* key_frame_it,
71 UnorderedFrameList* free_frames);
72 int CleanUpOldOrEmptyFrames(VCMDecodingState* decoding_state,
73 UnorderedFrameList* free_frames);
74 void Reset(UnorderedFrameList* free_frames);
77 class VCMJitterBuffer {
79 VCMJitterBuffer(Clock* clock,
80 EventFactory* event_factory);
81 virtual ~VCMJitterBuffer();
83 // Makes |this| a deep copy of |rhs|.
84 void CopyFrom(const VCMJitterBuffer& rhs);
86 // Initializes and starts jitter buffer.
89 // Signals all internal events and stops the jitter buffer.
92 // Returns true if the jitter buffer is running.
95 // Empty the jitter buffer of all its data.
98 // Get the number of received frames, by type, since the jitter buffer
100 std::map<FrameType, uint32_t> FrameStatistics() const;
102 // The number of packets discarded by the jitter buffer because the decoder
103 // won't be able to decode them.
104 int num_not_decodable_packets() const;
106 // Gets number of packets discarded by the jitter buffer.
107 int num_discarded_packets() const;
109 // Statistics, Calculate frame and bit rates.
110 void IncomingRateStatistics(unsigned int* framerate,
111 unsigned int* bitrate);
113 // Checks if the packet sequence will be complete if the next frame would be
114 // grabbed for decoding. That is, if a frame has been lost between the
115 // last decoded frame and the next, or if the next frame is missing one
117 bool CompleteSequenceWithNextFrame();
119 // Wait |max_wait_time_ms| for a complete frame to arrive.
120 // The function returns true once such a frame is found, its corresponding
121 // timestamp is returned. Otherwise, returns false.
122 bool NextCompleteTimestamp(uint32_t max_wait_time_ms, uint32_t* timestamp);
124 // Locates a frame for decoding (even an incomplete) without delay.
125 // The function returns true once such a frame is found, its corresponding
126 // timestamp is returned. Otherwise, returns false.
127 bool NextMaybeIncompleteTimestamp(uint32_t* timestamp);
129 // Extract frame corresponding to input timestamp.
130 // Frame will be set to a decoding state.
131 VCMEncodedFrame* ExtractAndSetDecode(uint32_t timestamp);
133 // Releases a frame returned from the jitter buffer, should be called when
134 // done with decoding.
135 void ReleaseFrame(VCMEncodedFrame* frame);
137 // Returns the time in ms when the latest packet was inserted into the frame.
138 // Retransmitted is set to true if any of the packets belonging to the frame
139 // has been retransmitted.
140 int64_t LastPacketTime(const VCMEncodedFrame* frame,
141 bool* retransmitted) const;
143 // Inserts a packet into a frame returned from GetFrame().
144 // If the return value is <= 0, |frame| is invalidated and the pointer must
145 // be dropped after this function returns.
146 VCMFrameBufferEnum InsertPacket(const VCMPacket& packet,
147 bool* retransmitted);
149 // Returns the estimated jitter in milliseconds.
150 uint32_t EstimatedJitterMs();
152 // Updates the round-trip time estimate.
153 void UpdateRtt(uint32_t rtt_ms);
155 // Set the NACK mode. |highRttNackThreshold| is an RTT threshold in ms above
156 // which NACK will be disabled if the NACK mode is |kNackHybrid|, -1 meaning
157 // that NACK is always enabled in the hybrid mode.
158 // |lowRttNackThreshold| is an RTT threshold in ms below which we expect to
159 // rely on NACK only, and therefore are using larger buffers to have time to
160 // wait for retransmissions.
161 void SetNackMode(VCMNackMode mode, int low_rtt_nack_threshold_ms,
162 int high_rtt_nack_threshold_ms);
164 void SetNackSettings(size_t max_nack_list_size,
165 int max_packet_age_to_nack,
166 int max_incomplete_time_ms);
168 // Returns the current NACK mode.
169 VCMNackMode nack_mode() const;
171 // Returns a list of the sequence numbers currently missing.
172 uint16_t* GetNackList(uint16_t* nack_list_size, bool* request_key_frame);
174 // Set decode error mode - Should not be changed in the middle of the
175 // session. Changes will not influence frames already in the buffer.
176 void SetDecodeErrorMode(VCMDecodeErrorMode error_mode);
177 int64_t LastDecodedTimestamp() const;
178 VCMDecodeErrorMode decode_error_mode() const {return decode_error_mode_;}
180 // Used to compute time of complete continuous frames. Returns the timestamps
181 // corresponding to the start and end of the continuous complete buffer.
182 void RenderBufferSize(uint32_t* timestamp_start, uint32_t* timestamp_end);
185 class SequenceNumberLessThan {
187 bool operator() (const uint16_t& sequence_number1,
188 const uint16_t& sequence_number2) const {
189 return IsNewerSequenceNumber(sequence_number2, sequence_number1);
192 typedef std::set<uint16_t, SequenceNumberLessThan> SequenceNumberSet;
194 // Gets the frame assigned to the timestamp of the packet. May recycle
195 // existing frames if no free frames are available. Returns an error code if
196 // failing, or kNoError on success.
197 VCMFrameBufferEnum GetFrame(const VCMPacket& packet, VCMFrameBuffer** frame);
198 void CopyFrames(FrameList* to_list, const FrameList& from_list);
199 void CopyFrames(FrameList* to_list, const FrameList& from_list, int* index);
200 // Returns true if |frame| is continuous in |decoding_state|, not taking
201 // decodable frames into account.
202 bool IsContinuousInState(const VCMFrameBuffer& frame,
203 const VCMDecodingState& decoding_state) const;
204 // Returns true if |frame| is continuous in the |last_decoded_state_|, taking
205 // all decodable frames into account.
206 bool IsContinuous(const VCMFrameBuffer& frame) const;
207 // Looks for frames in |incomplete_frames_| which are continuous in
208 // |last_decoded_state_| taking all decodable frames into account. Starts
209 // the search from |new_frame|.
210 void FindAndInsertContinuousFrames(const VCMFrameBuffer& new_frame);
211 VCMFrameBuffer* NextFrame() const;
212 // Returns true if the NACK list was updated to cover sequence numbers up to
213 // |sequence_number|. If false a key frame is needed to get into a state where
214 // we can continue decoding.
215 bool UpdateNackList(uint16_t sequence_number);
216 bool TooLargeNackList() const;
217 // Returns true if the NACK list was reduced without problem. If false a key
218 // frame is needed to get into a state where we can continue decoding.
219 bool HandleTooLargeNackList();
220 bool MissingTooOldPacket(uint16_t latest_sequence_number) const;
221 // Returns true if the too old packets was successfully removed from the NACK
222 // list. If false, a key frame is needed to get into a state where we can
223 // continue decoding.
224 bool HandleTooOldPackets(uint16_t latest_sequence_number);
225 // Drops all packets in the NACK list up until |last_decoded_sequence_number|.
226 void DropPacketsFromNackList(uint16_t last_decoded_sequence_number);
228 void ReleaseFrameIfNotDecoding(VCMFrameBuffer* frame);
230 // Gets an empty frame, creating a new frame if necessary (i.e. increases
231 // jitter buffer size).
232 VCMFrameBuffer* GetEmptyFrame();
234 // Attempts to increase the size of the jitter buffer. Returns true on
235 // success, false otherwise.
236 bool TryToIncreaseJitterBufferSize();
238 // Recycles oldest frames until a key frame is found. Used if jitter buffer is
239 // completely full. Returns true if a key frame was found.
240 bool RecycleFramesUntilKeyFrame();
242 // Updates the frame statistics.
243 // Counts only complete frames, so decodable incomplete frames will not be
245 void CountFrame(const VCMFrameBuffer& frame);
247 // Update rolling average of packets per frame.
248 void UpdateAveragePacketsPerFrame(int current_number_packets_);
250 // Cleans the frame list in the JB from old/empty frames.
251 // Should only be called prior to actual use.
252 void CleanUpOldOrEmptyFrames();
254 // Returns true if |packet| is likely to have been retransmitted.
255 bool IsPacketRetransmitted(const VCMPacket& packet) const;
257 // The following three functions update the jitter estimate with the
258 // payload size, receive time and RTP timestamp of a frame.
259 void UpdateJitterEstimate(const VCMJitterSample& sample,
260 bool incomplete_frame);
261 void UpdateJitterEstimate(const VCMFrameBuffer& frame, bool incomplete_frame);
262 void UpdateJitterEstimate(int64_t latest_packet_time_ms,
264 unsigned int frame_size,
265 bool incomplete_frame);
267 // Returns true if we should wait for retransmissions, false otherwise.
268 bool WaitForRetransmissions();
270 int NonContinuousOrIncompleteDuration();
272 uint16_t EstimatedLowSequenceNumber(const VCMFrameBuffer& frame) const;
275 // If we are running (have started) or not.
277 CriticalSectionWrapper* crit_sect_;
278 // Event to signal when we have a frame ready for decoder.
279 scoped_ptr<EventWrapper> frame_event_;
280 // Event to signal when we have received a packet.
281 scoped_ptr<EventWrapper> packet_event_;
282 // Number of allocated frames.
283 int max_number_of_frames_;
284 // Array of pointers to the frames in jitter buffer.
285 VCMFrameBuffer* frame_buffers_[kMaxNumberOfFrames];
286 UnorderedFrameList free_frames_;
287 FrameList decodable_frames_;
288 FrameList incomplete_frames_;
289 VCMDecodingState last_decoded_state_;
290 bool first_packet_since_reset_;
293 // Frame counts for each type (key, delta, ...)
294 std::map<FrameType, uint32_t> receive_statistics_;
295 // Latest calculated frame rates of incoming stream.
296 unsigned int incoming_frame_rate_;
297 unsigned int incoming_frame_count_;
298 int64_t time_last_incoming_frame_count_;
299 unsigned int incoming_bit_count_;
300 unsigned int incoming_bit_rate_;
301 unsigned int drop_count_; // Frame drop counter.
302 // Number of frames in a row that have been too old.
303 int num_consecutive_old_frames_;
304 // Number of packets in a row that have been too old.
305 int num_consecutive_old_packets_;
306 // Number of packets discarded by the jitter buffer.
307 int num_discarded_packets_;
309 // Jitter estimation.
310 // Filter for estimating jitter.
311 VCMJitterEstimator jitter_estimate_;
312 // Calculates network delays used for jitter calculations.
313 VCMInterFrameDelay inter_frame_delay_;
314 VCMJitterSample waiting_for_completion_;
317 // NACK and retransmissions.
318 VCMNackMode nack_mode_;
319 int low_rtt_nack_threshold_ms_;
320 int high_rtt_nack_threshold_ms_;
321 // Holds the internal NACK list (the missing sequence numbers).
322 SequenceNumberSet missing_sequence_numbers_;
323 uint16_t latest_received_sequence_number_;
324 std::vector<uint16_t> nack_seq_nums_;
325 size_t max_nack_list_size_;
326 int max_packet_age_to_nack_; // Measured in sequence numbers.
327 int max_incomplete_time_ms_;
329 VCMDecodeErrorMode decode_error_mode_;
330 // Estimated rolling average of packets per frame
331 float average_packets_per_frame_;
332 // average_packets_per_frame converges fast if we have fewer than this many
335 DISALLOW_COPY_AND_ASSIGN(VCMJitterBuffer);
337 } // namespace webrtc
339 #endif // WEBRTC_MODULES_VIDEO_CODING_MAIN_SOURCE_JITTER_BUFFER_H_