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/*
* Copyright (c) 2013 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 "webrtc/modules/audio_coding/neteq/decision_logic_normal.h"
#include <assert.h>
#include <algorithm>
#include "webrtc/modules/audio_coding/neteq/buffer_level_filter.h"
#include "webrtc/modules/audio_coding/neteq/decoder_database.h"
#include "webrtc/modules/audio_coding/neteq/delay_manager.h"
#include "webrtc/modules/audio_coding/neteq/expand.h"
#include "webrtc/modules/audio_coding/neteq/packet_buffer.h"
#include "webrtc/modules/audio_coding/neteq/sync_buffer.h"
#include "webrtc/modules/interface/module_common_types.h"
namespace webrtc {
Operations DecisionLogicNormal::GetDecisionSpecialized(
const SyncBuffer& sync_buffer,
const Expand& expand,
int decoder_frame_length,
const RTPHeader* packet_header,
Modes prev_mode,
bool play_dtmf,
bool* reset_decoder) {
assert(playout_mode_ == kPlayoutOn || playout_mode_ == kPlayoutStreaming);
// Guard for errors, to avoid getting stuck in error mode.
if (prev_mode == kModeError) {
if (!packet_header) {
return kExpand;
} else {
return kUndefined; // Use kUndefined to flag for a reset.
}
}
uint32_t target_timestamp = sync_buffer.end_timestamp();
uint32_t available_timestamp = 0;
bool is_cng_packet = false;
if (packet_header) {
available_timestamp = packet_header->timestamp;
is_cng_packet =
decoder_database_->IsComfortNoise(packet_header->payloadType);
}
if (is_cng_packet) {
return CngOperation(prev_mode, target_timestamp, available_timestamp);
}
// Handle the case with no packet at all available (except maybe DTMF).
if (!packet_header) {
return NoPacket(play_dtmf);
}
// If the expand period was very long, reset NetEQ since it is likely that the
// sender was restarted.
if (num_consecutive_expands_ > kReinitAfterExpands) {
*reset_decoder = true;
return kNormal;
}
const uint32_t five_seconds_samples = 5 * 8000 * fs_mult_;
// Check if the required packet is available.
if (target_timestamp == available_timestamp) {
return ExpectedPacketAvailable(prev_mode, play_dtmf);
} else if (!PacketBuffer::IsObsoleteTimestamp(
available_timestamp, target_timestamp, five_seconds_samples)) {
return FuturePacketAvailable(sync_buffer, expand, decoder_frame_length,
prev_mode, target_timestamp,
available_timestamp, play_dtmf);
} else {
// This implies that available_timestamp < target_timestamp, which can
// happen when a new stream or codec is received. Signal for a reset.
return kUndefined;
}
}
Operations DecisionLogicNormal::CngOperation(Modes prev_mode,
uint32_t target_timestamp,
uint32_t available_timestamp) {
// Signed difference between target and available timestamp.
int32_t timestamp_diff = (generated_noise_samples_ + target_timestamp) -
available_timestamp;
int32_t optimal_level_samp =
(delay_manager_->TargetLevel() * packet_length_samples_) >> 8;
int32_t excess_waiting_time_samp = -timestamp_diff - optimal_level_samp;
if (excess_waiting_time_samp > optimal_level_samp / 2) {
// The waiting time for this packet will be longer than 1.5
// times the wanted buffer delay. Advance the clock to cut
// waiting time down to the optimal.
generated_noise_samples_ += excess_waiting_time_samp;
timestamp_diff += excess_waiting_time_samp;
}
if (timestamp_diff < 0 && prev_mode == kModeRfc3389Cng) {
// Not time to play this packet yet. Wait another round before using this
// packet. Keep on playing CNG from previous CNG parameters.
return kRfc3389CngNoPacket;
} else {
// Otherwise, go for the CNG packet now.
return kRfc3389Cng;
}
}
Operations DecisionLogicNormal::NoPacket(bool play_dtmf) {
if (cng_state_ == kCngRfc3389On) {
// Keep on playing comfort noise.
return kRfc3389CngNoPacket;
} else if (cng_state_ == kCngInternalOn) {
// Keep on playing codec internal comfort noise.
return kCodecInternalCng;
} else if (play_dtmf) {
return kDtmf;
} else {
// Nothing to play, do expand.
return kExpand;
}
}
Operations DecisionLogicNormal::ExpectedPacketAvailable(Modes prev_mode,
bool play_dtmf) {
if (prev_mode != kModeExpand && !play_dtmf) {
// Check criterion for time-stretching.
int low_limit, high_limit;
delay_manager_->BufferLimits(&low_limit, &high_limit);
if ((buffer_level_filter_->filtered_current_level() >= high_limit &&
TimescaleAllowed()) ||
buffer_level_filter_->filtered_current_level() >= high_limit << 2) {
// Buffer level higher than limit and time-scaling allowed,
// or buffer level really high.
return kAccelerate;
} else if ((buffer_level_filter_->filtered_current_level() < low_limit)
&& TimescaleAllowed()) {
return kPreemptiveExpand;
}
}
return kNormal;
}
Operations DecisionLogicNormal::FuturePacketAvailable(
const SyncBuffer& sync_buffer,
const Expand& expand,
int decoder_frame_length,
Modes prev_mode,
uint32_t target_timestamp,
uint32_t available_timestamp,
bool play_dtmf) {
// Required packet is not available, but a future packet is.
// Check if we should continue with an ongoing expand because the new packet
// is too far into the future.
uint32_t timestamp_leap = available_timestamp - target_timestamp;
if ((prev_mode == kModeExpand) &&
!ReinitAfterExpands(timestamp_leap) &&
!MaxWaitForPacket() &&
PacketTooEarly(timestamp_leap) &&
UnderTargetLevel()) {
if (play_dtmf) {
// Still have DTMF to play, so do not do expand.
return kDtmf;
} else {
// Nothing to play.
return kExpand;
}
}
const int samples_left = static_cast<int>(sync_buffer.FutureLength() -
expand.overlap_length());
const int cur_size_samples = samples_left +
packet_buffer_.NumPacketsInBuffer() * decoder_frame_length;
// If previous was comfort noise, then no merge is needed.
if (prev_mode == kModeRfc3389Cng ||
prev_mode == kModeCodecInternalCng) {
// Keep the same delay as before the CNG (or maximum 70 ms in buffer as
// safety precaution), but make sure that the number of samples in buffer
// is no higher than 4 times the optimal level. (Note that TargetLevel()
// is in Q8.)
int32_t timestamp_diff = (generated_noise_samples_ + target_timestamp) -
available_timestamp;
if (timestamp_diff >= 0 ||
cur_size_samples >
4 * ((delay_manager_->TargetLevel() * packet_length_samples_) >> 8)) {
// Time to play this new packet.
return kNormal;
} else {
// Too early to play this new packet; keep on playing comfort noise.
if (prev_mode == kModeRfc3389Cng) {
return kRfc3389CngNoPacket;
} else { // prevPlayMode == kModeCodecInternalCng.
return kCodecInternalCng;
}
}
}
// Do not merge unless we have done an expand before.
// (Convert kAllowMergeWithoutExpand from ms to samples by multiplying with
// fs_mult_ * 8 = fs / 1000.)
if (prev_mode == kModeExpand ||
(decoder_frame_length < output_size_samples_ &&
cur_size_samples > kAllowMergeWithoutExpandMs * fs_mult_ * 8)) {
return kMerge;
} else if (play_dtmf) {
// Play DTMF instead of expand.
return kDtmf;
} else {
return kExpand;
}
}
bool DecisionLogicNormal::UnderTargetLevel() const {
return buffer_level_filter_->filtered_current_level() <=
delay_manager_->TargetLevel();
}
bool DecisionLogicNormal::ReinitAfterExpands(uint32_t timestamp_leap) const {
return timestamp_leap >=
static_cast<uint32_t>(output_size_samples_ * kReinitAfterExpands);
}
bool DecisionLogicNormal::PacketTooEarly(uint32_t timestamp_leap) const {
return timestamp_leap >
static_cast<uint32_t>(output_size_samples_ * num_consecutive_expands_);
}
bool DecisionLogicNormal::MaxWaitForPacket() const {
return num_consecutive_expands_ >= kMaxWaitForPacket;
}
} // namespace webrtc
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