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* Copyright (c) 2012 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.
#include <string.h> // Provide access to size_t.
#include <string>
#include <vector>
#include "webrtc/api/optional.h"
#include "webrtc/common_types.h"
#include "webrtc/modules/audio_coding/neteq/audio_decoder_impl.h"
#include "webrtc/rtc_base/constructormagic.h"
#include "webrtc/rtc_base/scoped_ref_ptr.h"
#include "webrtc/typedefs.h"
namespace webrtc {
// Forward declarations.
class AudioFrame;
class AudioDecoderFactory;
struct NetEqNetworkStatistics {
uint16_t current_buffer_size_ms; // Current jitter buffer size in ms.
uint16_t preferred_buffer_size_ms; // Target buffer size in ms.
uint16_t jitter_peaks_found; // 1 if adding extra delay due to peaky
// jitter; 0 otherwise.
uint16_t packet_loss_rate; // Loss rate (network + late) in Q14.
uint16_t expand_rate; // Fraction (of original stream) of synthesized
// audio inserted through expansion (in Q14).
uint16_t speech_expand_rate; // Fraction (of original stream) of synthesized
// speech inserted through expansion (in Q14).
uint16_t preemptive_rate; // Fraction of data inserted through pre-emptive
// expansion (in Q14).
uint16_t accelerate_rate; // Fraction of data removed through acceleration
// (in Q14).
uint16_t secondary_decoded_rate; // Fraction of data coming from FEC/RED
// decoding (in Q14).
uint16_t secondary_discarded_rate; // Fraction of discarded FEC/RED data (in
// Q14).
int32_t clockdrift_ppm; // Average clock-drift in parts-per-million
// (positive or negative).
size_t added_zero_samples; // Number of zero samples added in "off" mode.
// Statistics for packet waiting times, i.e., the time between a packet
// arrives until it is decoded.
int mean_waiting_time_ms;
int median_waiting_time_ms;
int min_waiting_time_ms;
int max_waiting_time_ms;
// NetEq statistics that persist over the lifetime of the class.
// These metrics are never reset.
struct NetEqLifetimeStatistics {
// Total number of audio samples received, including synthesized samples.
uint64_t total_samples_received = 0;
// Total number of inbound audio samples that are based on synthesized data to
// conceal packet loss.
uint64_t concealed_samples = 0;
enum NetEqPlayoutMode {
// This is the interface class for NetEq.
class NetEq {
enum BackgroundNoiseMode {
kBgnOn, // Default behavior with eternal noise.
kBgnFade, // Noise fades to zero after some time.
kBgnOff // Background noise is always zero.
struct Config {
: sample_rate_hz(16000),
// |max_delay_ms| has the same effect as calling SetMaximumDelay().
enable_fast_accelerate(false) {}
std::string ToString() const;
int sample_rate_hz; // Initial value. Will change with input data.
bool enable_post_decode_vad;
size_t max_packets_in_buffer;
int max_delay_ms;
BackgroundNoiseMode background_noise_mode;
NetEqPlayoutMode playout_mode;
bool enable_fast_accelerate;
bool enable_muted_state = false;
enum ReturnCodes {
kOK = 0,
kFail = -1,
kNotImplemented = -2
// Creates a new NetEq object, with parameters set in |config|. The |config|
// object will only have to be valid for the duration of the call to this
// method.
static NetEq* Create(
const NetEq::Config& config,
const rtc::scoped_refptr<AudioDecoderFactory>& decoder_factory);
virtual ~NetEq() {}
// Inserts a new packet into NetEq. The |receive_timestamp| is an indication
// of the time when the packet was received, and should be measured with
// the same tick rate as the RTP timestamp of the current payload.
// Returns 0 on success, -1 on failure.
virtual int InsertPacket(const RTPHeader& rtp_header,
rtc::ArrayView<const uint8_t> payload,
uint32_t receive_timestamp) = 0;
// Lets NetEq know that a packet arrived with an empty payload. This typically
// happens when empty packets are used for probing the network channel, and
// these packets use RTP sequence numbers from the same series as the actual
// audio packets.
virtual void InsertEmptyPacket(const RTPHeader& rtp_header) = 0;
// Instructs NetEq to deliver 10 ms of audio data. The data is written to
// |audio_frame|. All data in |audio_frame| is wiped; |data_|, |speech_type_|,
// |num_channels_|, |sample_rate_hz_|, |samples_per_channel_|, and
// |vad_activity_| are updated upon success. If an error is returned, some
// fields may not have been updated, or may contain inconsistent values.
// If muted state is enabled (through Config::enable_muted_state), |muted|
// may be set to true after a prolonged expand period. When this happens, the
// |data_| in |audio_frame| is not written, but should be interpreted as being
// all zeros.
// Returns kOK on success, or kFail in case of an error.
virtual int GetAudio(AudioFrame* audio_frame, bool* muted) = 0;
// Replaces the current set of decoders with the given one.
virtual void SetCodecs(const std::map<int, SdpAudioFormat>& codecs) = 0;
// Associates |rtp_payload_type| with |codec| and |codec_name|, and stores the
// information in the codec database. Returns 0 on success, -1 on failure.
// The name is only used to provide information back to the caller about the
// decoders. Hence, the name is arbitrary, and may be empty.
virtual int RegisterPayloadType(NetEqDecoder codec,
const std::string& codec_name,
uint8_t rtp_payload_type) = 0;
// Provides an externally created decoder object |decoder| to insert in the
// decoder database. The decoder implements a decoder of type |codec| and
// associates it with |rtp_payload_type| and |codec_name|. Returns kOK on
// success, kFail on failure. The name is only used to provide information
// back to the caller about the decoders. Hence, the name is arbitrary, and
// may be empty.
virtual int RegisterExternalDecoder(AudioDecoder* decoder,
NetEqDecoder codec,
const std::string& codec_name,
uint8_t rtp_payload_type) = 0;
// Associates |rtp_payload_type| with the given codec, which NetEq will
// instantiate when it needs it. Returns true iff successful.
virtual bool RegisterPayloadType(int rtp_payload_type,
const SdpAudioFormat& audio_format) = 0;
// Removes |rtp_payload_type| from the codec database. Returns 0 on success,
// -1 on failure. Removing a payload type that is not registered is ok and
// will not result in an error.
virtual int RemovePayloadType(uint8_t rtp_payload_type) = 0;
// Removes all payload types from the codec database.
virtual void RemoveAllPayloadTypes() = 0;
// Sets a minimum delay in millisecond for packet buffer. The minimum is
// maintained unless a higher latency is dictated by channel condition.
// Returns true if the minimum is successfully applied, otherwise false is
// returned.
virtual bool SetMinimumDelay(int delay_ms) = 0;
// Sets a maximum delay in milliseconds for packet buffer. The latency will
// not exceed the given value, even required delay (given the channel
// conditions) is higher. Calling this method has the same effect as setting
// the |max_delay_ms| value in the NetEq::Config struct.
virtual bool SetMaximumDelay(int delay_ms) = 0;
// The smallest latency required. This is computed bases on inter-arrival
// time and internal NetEq logic. Note that in computing this latency none of
// the user defined limits (applied by calling setMinimumDelay() and/or
// SetMaximumDelay()) are applied.
virtual int LeastRequiredDelayMs() const = 0;
// Not implemented.
virtual int SetTargetDelay() = 0;
// Returns the current target delay in ms. This includes any extra delay
// requested through SetMinimumDelay.
virtual int TargetDelayMs() = 0;
// Returns the current total delay (packet buffer and sync buffer) in ms.
virtual int CurrentDelayMs() const = 0;
// Returns the current total delay (packet buffer and sync buffer) in ms,
// with smoothing applied to even out short-time fluctuations due to jitter.
// The packet buffer part of the delay is not updated during DTX/CNG periods.
virtual int FilteredCurrentDelayMs() const = 0;
// Sets the playout mode to |mode|.
// Deprecated. Set the mode in the Config struct passed to the constructor.
// TODO(henrik.lundin) Delete.
virtual void SetPlayoutMode(NetEqPlayoutMode mode) = 0;
// Returns the current playout mode.
// Deprecated.
// TODO(henrik.lundin) Delete.
virtual NetEqPlayoutMode PlayoutMode() const = 0;
// Writes the current network statistics to |stats|. The statistics are reset
// after the call.
virtual int NetworkStatistics(NetEqNetworkStatistics* stats) = 0;
// Returns a copy of this class's lifetime statistics. These statistics are
// never reset.
virtual NetEqLifetimeStatistics GetLifetimeStatistics() const = 0;
// Writes the current RTCP statistics to |stats|. The statistics are reset
// and a new report period is started with the call.
virtual void GetRtcpStatistics(RtcpStatistics* stats) = 0;
// Same as RtcpStatistics(), but does not reset anything.
virtual void GetRtcpStatisticsNoReset(RtcpStatistics* stats) = 0;
// Enables post-decode VAD. When enabled, GetAudio() will return
// kOutputVADPassive when the signal contains no speech.
virtual void EnableVad() = 0;
// Disables post-decode VAD.
virtual void DisableVad() = 0;
// Returns the RTP timestamp for the last sample delivered by GetAudio().
// The return value will be empty if no valid timestamp is available.
virtual rtc::Optional<uint32_t> GetPlayoutTimestamp() const = 0;
// Returns the sample rate in Hz of the audio produced in the last GetAudio
// call. If GetAudio has not been called yet, the configured sample rate
// (Config::sample_rate_hz) is returned.
virtual int last_output_sample_rate_hz() const = 0;
// Returns info about the decoder for the given payload type, or an empty
// value if we have no decoder for that payload type.
virtual rtc::Optional<CodecInst> GetDecoder(int payload_type) const = 0;
// Returns the decoder format for the given payload type. Returns empty if no
// such payload type was registered.
virtual rtc::Optional<SdpAudioFormat> GetDecoderFormat(
int payload_type) const = 0;
// Not implemented.
virtual int SetTargetNumberOfChannels() = 0;
// Not implemented.
virtual int SetTargetSampleRate() = 0;
// Flushes both the packet buffer and the sync buffer.
virtual void FlushBuffers() = 0;
// Current usage of packet-buffer and it's limits.
virtual void PacketBufferStatistics(int* current_num_packets,
int* max_num_packets) const = 0;
// Enables NACK and sets the maximum size of the NACK list, which should be
// positive and no larger than Nack::kNackListSizeLimit. If NACK is already
// enabled then the maximum NACK list size is modified accordingly.
virtual void EnableNack(size_t max_nack_list_size) = 0;
virtual void DisableNack() = 0;
// Returns a list of RTP sequence numbers corresponding to packets to be
// retransmitted, given an estimate of the round-trip time in milliseconds.
virtual std::vector<uint16_t> GetNackList(
int64_t round_trip_time_ms) const = 0;
// Returns a vector containing the timestamps of the packets that were decoded
// in the last GetAudio call. If no packets were decoded in the last call, the
// vector is empty.
// Mainly intended for testing.
virtual std::vector<uint32_t> LastDecodedTimestamps() const = 0;
// Returns the length of the audio yet to play in the sync buffer.
// Mainly intended for testing.
virtual int SyncBufferSizeMs() const = 0;
NetEq() {}
} // namespace webrtc