195 lines
7.1 KiB
C++
195 lines
7.1 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "modules/video_coding/receiver.h"
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#include <assert.h>
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#include <cstdint>
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#include <cstdlib>
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#include <utility>
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#include <vector>
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#include "absl/memory/memory.h"
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#include "api/video/encoded_image.h"
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#include "modules/video_coding/encoded_frame.h"
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#include "modules/video_coding/internal_defines.h"
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#include "modules/video_coding/jitter_buffer_common.h"
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#include "rtc_base/logging.h"
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#include "rtc_base/numerics/safe_conversions.h"
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#include "rtc_base/trace_event.h"
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#include "system_wrappers/include/clock.h"
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namespace webrtc {
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enum { kMaxReceiverDelayMs = 10000 };
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VCMReceiver::VCMReceiver(VCMTiming* timing, Clock* clock)
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: VCMReceiver::VCMReceiver(timing,
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clock,
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absl::WrapUnique(EventWrapper::Create()),
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absl::WrapUnique(EventWrapper::Create())) {}
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VCMReceiver::VCMReceiver(VCMTiming* timing,
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Clock* clock,
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std::unique_ptr<EventWrapper> receiver_event,
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std::unique_ptr<EventWrapper> jitter_buffer_event)
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: clock_(clock),
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jitter_buffer_(clock_, std::move(jitter_buffer_event)),
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timing_(timing),
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render_wait_event_(std::move(receiver_event)),
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max_video_delay_ms_(kMaxVideoDelayMs) {
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jitter_buffer_.Start();
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}
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VCMReceiver::~VCMReceiver() {
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render_wait_event_->Set();
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}
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int32_t VCMReceiver::InsertPacket(const VCMPacket& packet) {
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// Insert the packet into the jitter buffer. The packet can either be empty or
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// contain media at this point.
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bool retransmitted = false;
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const VCMFrameBufferEnum ret =
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jitter_buffer_.InsertPacket(packet, &retransmitted);
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if (ret == kOldPacket) {
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return VCM_OK;
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} else if (ret == kFlushIndicator) {
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return VCM_FLUSH_INDICATOR;
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} else if (ret < 0) {
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return VCM_JITTER_BUFFER_ERROR;
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}
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if (ret == kCompleteSession && !retransmitted) {
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// We don't want to include timestamps which have suffered from
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// retransmission here, since we compensate with extra retransmission
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// delay within the jitter estimate.
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timing_->IncomingTimestamp(packet.timestamp, clock_->TimeInMilliseconds());
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}
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return VCM_OK;
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}
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VCMEncodedFrame* VCMReceiver::FrameForDecoding(uint16_t max_wait_time_ms,
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bool prefer_late_decoding) {
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const int64_t start_time_ms = clock_->TimeInMilliseconds();
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uint32_t frame_timestamp = 0;
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int min_playout_delay_ms = -1;
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int max_playout_delay_ms = -1;
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int64_t render_time_ms = 0;
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// Exhaust wait time to get a complete frame for decoding.
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VCMEncodedFrame* found_frame =
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jitter_buffer_.NextCompleteFrame(max_wait_time_ms);
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if (found_frame) {
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frame_timestamp = found_frame->Timestamp();
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min_playout_delay_ms = found_frame->EncodedImage().playout_delay_.min_ms;
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max_playout_delay_ms = found_frame->EncodedImage().playout_delay_.max_ms;
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} else {
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return nullptr;
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}
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if (min_playout_delay_ms >= 0)
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timing_->set_min_playout_delay(min_playout_delay_ms);
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if (max_playout_delay_ms >= 0)
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timing_->set_max_playout_delay(max_playout_delay_ms);
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// We have a frame - Set timing and render timestamp.
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timing_->SetJitterDelay(jitter_buffer_.EstimatedJitterMs());
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const int64_t now_ms = clock_->TimeInMilliseconds();
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timing_->UpdateCurrentDelay(frame_timestamp);
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render_time_ms = timing_->RenderTimeMs(frame_timestamp, now_ms);
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// Check render timing.
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bool timing_error = false;
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// Assume that render timing errors are due to changes in the video stream.
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if (render_time_ms < 0) {
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timing_error = true;
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} else if (std::abs(render_time_ms - now_ms) > max_video_delay_ms_) {
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int frame_delay = static_cast<int>(std::abs(render_time_ms - now_ms));
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RTC_LOG(LS_WARNING)
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<< "A frame about to be decoded is out of the configured "
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"delay bounds ("
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<< frame_delay << " > " << max_video_delay_ms_
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<< "). Resetting the video jitter buffer.";
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timing_error = true;
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} else if (static_cast<int>(timing_->TargetVideoDelay()) >
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max_video_delay_ms_) {
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RTC_LOG(LS_WARNING) << "The video target delay has grown larger than "
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<< max_video_delay_ms_
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<< " ms. Resetting jitter buffer.";
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timing_error = true;
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}
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if (timing_error) {
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// Timing error => reset timing and flush the jitter buffer.
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jitter_buffer_.Flush();
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timing_->Reset();
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return NULL;
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}
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if (prefer_late_decoding) {
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// Decode frame as close as possible to the render timestamp.
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const int32_t available_wait_time =
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max_wait_time_ms -
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static_cast<int32_t>(clock_->TimeInMilliseconds() - start_time_ms);
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uint16_t new_max_wait_time =
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static_cast<uint16_t>(VCM_MAX(available_wait_time, 0));
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uint32_t wait_time_ms = rtc::saturated_cast<uint32_t>(
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timing_->MaxWaitingTime(render_time_ms, clock_->TimeInMilliseconds()));
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if (new_max_wait_time < wait_time_ms) {
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// We're not allowed to wait until the frame is supposed to be rendered,
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// waiting as long as we're allowed to avoid busy looping, and then return
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// NULL. Next call to this function might return the frame.
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render_wait_event_->Wait(new_max_wait_time);
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return NULL;
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}
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// Wait until it's time to render.
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render_wait_event_->Wait(wait_time_ms);
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}
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// Extract the frame from the jitter buffer and set the render time.
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VCMEncodedFrame* frame = jitter_buffer_.ExtractAndSetDecode(frame_timestamp);
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if (frame == NULL) {
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return NULL;
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}
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frame->SetRenderTime(render_time_ms);
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TRACE_EVENT_ASYNC_STEP1("webrtc", "Video", frame->Timestamp(), "SetRenderTS",
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"render_time", frame->RenderTimeMs());
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if (!frame->Complete()) {
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// Update stats for incomplete frames.
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bool retransmitted = false;
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const int64_t last_packet_time_ms =
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jitter_buffer_.LastPacketTime(frame, &retransmitted);
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if (last_packet_time_ms >= 0 && !retransmitted) {
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// We don't want to include timestamps which have suffered from
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// retransmission here, since we compensate with extra retransmission
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// delay within the jitter estimate.
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timing_->IncomingTimestamp(frame_timestamp, last_packet_time_ms);
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}
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}
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return frame;
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}
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void VCMReceiver::ReleaseFrame(VCMEncodedFrame* frame) {
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jitter_buffer_.ReleaseFrame(frame);
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}
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void VCMReceiver::SetNackSettings(size_t max_nack_list_size,
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int max_packet_age_to_nack,
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int max_incomplete_time_ms) {
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jitter_buffer_.SetNackSettings(max_nack_list_size, max_packet_age_to_nack,
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max_incomplete_time_ms);
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}
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std::vector<uint16_t> VCMReceiver::NackList(bool* request_key_frame) {
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return jitter_buffer_.GetNackList(request_key_frame);
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}
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} // namespace webrtc
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