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/*
* Copyright (c) 2016 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 "media/base/video_broadcaster.h"
#include <algorithm>
#include <vector>
#include "absl/types/optional.h"
#include "api/video/i420_buffer.h"
#include "api/video/video_rotation.h"
#include "media/base/video_common.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
namespace rtc {
VideoBroadcaster::VideoBroadcaster() = default;
VideoBroadcaster::~VideoBroadcaster() = default;
void VideoBroadcaster::AddOrUpdateSink(
VideoSinkInterface<webrtc::VideoFrame>* sink,
const VideoSinkWants& wants) {
RTC_DCHECK(sink != nullptr);
webrtc::MutexLock lock(&sinks_and_wants_lock_);
if (!FindSinkPair(sink)) {
// `Sink` is a new sink, which didn't receive previous frame.
previous_frame_sent_to_all_sinks_ = false;
if (last_constraints_.has_value()) {
RTC_LOG(LS_INFO) << __func__ << " forwarding stored constraints min_fps "
<< last_constraints_->min_fps.value_or(-1) << " max_fps "
<< last_constraints_->max_fps.value_or(-1);
sink->OnConstraintsChanged(*last_constraints_);
}
}
VideoSourceBase::AddOrUpdateSink(sink, wants);
UpdateWants();
}
void VideoBroadcaster::RemoveSink(
VideoSinkInterface<webrtc::VideoFrame>* sink) {
RTC_DCHECK(sink != nullptr);
webrtc::MutexLock lock(&sinks_and_wants_lock_);
VideoSourceBase::RemoveSink(sink);
UpdateWants();
}
bool VideoBroadcaster::frame_wanted() const {
webrtc::MutexLock lock(&sinks_and_wants_lock_);
return !sink_pairs().empty();
}
VideoSinkWants VideoBroadcaster::wants() const {
webrtc::MutexLock lock(&sinks_and_wants_lock_);
return current_wants_;
}
void VideoBroadcaster::OnFrame(const webrtc::VideoFrame& frame) {
webrtc::MutexLock lock(&sinks_and_wants_lock_);
bool current_frame_was_discarded = false;
for (auto& sink_pair : sink_pairs()) {
if (sink_pair.wants.rotation_applied &&
frame.rotation() != webrtc::kVideoRotation_0) {
// Calls to OnFrame are not synchronized with changes to the sink wants.
// When rotation_applied is set to true, one or a few frames may get here
// with rotation still pending. Protect sinks that don't expect any
// pending rotation.
RTC_LOG(LS_VERBOSE) << "Discarding frame with unexpected rotation.";
sink_pair.sink->OnDiscardedFrame();
current_frame_was_discarded = true;
continue;
}
if (sink_pair.wants.black_frames) {
webrtc::VideoFrame black_frame =
webrtc::VideoFrame::Builder()
.set_video_frame_buffer(
GetBlackFrameBuffer(frame.width(), frame.height()))
.set_rotation(frame.rotation())
.set_timestamp_us(frame.timestamp_us())
.set_id(frame.id())
.build();
sink_pair.sink->OnFrame(black_frame);
} else if (!previous_frame_sent_to_all_sinks_ && frame.has_update_rect()) {
// Since last frame was not sent to some sinks, no reliable update
// information is available, so we need to clear the update rect.
webrtc::VideoFrame copy = frame;
copy.clear_update_rect();
sink_pair.sink->OnFrame(copy);
} else {
sink_pair.sink->OnFrame(frame);
}
}
previous_frame_sent_to_all_sinks_ = !current_frame_was_discarded;
}
void VideoBroadcaster::OnDiscardedFrame() {
webrtc::MutexLock lock(&sinks_and_wants_lock_);
for (auto& sink_pair : sink_pairs()) {
sink_pair.sink->OnDiscardedFrame();
}
}
void VideoBroadcaster::ProcessConstraints(
const webrtc::VideoTrackSourceConstraints& constraints) {
webrtc::MutexLock lock(&sinks_and_wants_lock_);
RTC_LOG(LS_INFO) << __func__ << " min_fps "
<< constraints.min_fps.value_or(-1) << " max_fps "
<< constraints.max_fps.value_or(-1) << " broadcasting to "
<< sink_pairs().size() << " sinks.";
last_constraints_ = constraints;
for (auto& sink_pair : sink_pairs())
sink_pair.sink->OnConstraintsChanged(constraints);
}
void VideoBroadcaster::UpdateWants() {
VideoSinkWants wants;
wants.rotation_applied = false;
wants.resolution_alignment = 1;
wants.aggregates.emplace(VideoSinkWants::Aggregates());
wants.is_active = false;
// TODO(webrtc:14451) : I think it makes sense to always
// "ignore" encoders that are not active. But that would
// probably require a controlled roll out with a field trials?
// To play it safe, only ignore inactive encoders is there is an
// active encoder using the new api (requested_resolution),
// this means that there is only a behavioural change when using new
// api.
bool ignore_inactive_encoders_old_api = false;
for (auto& sink : sink_pairs()) {
if (sink.wants.is_active && sink.wants.requested_resolution.has_value()) {
ignore_inactive_encoders_old_api = true;
break;
}
}
for (auto& sink : sink_pairs()) {
if (!sink.wants.is_active &&
(sink.wants.requested_resolution || ignore_inactive_encoders_old_api)) {
continue;
}
// wants.rotation_applied == ANY(sink.wants.rotation_applied)
if (sink.wants.rotation_applied) {
wants.rotation_applied = true;
}
// wants.max_pixel_count == MIN(sink.wants.max_pixel_count)
if (sink.wants.max_pixel_count < wants.max_pixel_count) {
wants.max_pixel_count = sink.wants.max_pixel_count;
}
// Select the minimum requested target_pixel_count, if any, of all sinks so
// that we don't over utilize the resources for any one.
// TODO(sprang): Consider using the median instead, since the limit can be
// expressed by max_pixel_count.
if (sink.wants.target_pixel_count &&
(!wants.target_pixel_count ||
(*sink.wants.target_pixel_count < *wants.target_pixel_count))) {
wants.target_pixel_count = sink.wants.target_pixel_count;
}
// Select the minimum for the requested max framerates.
if (sink.wants.max_framerate_fps < wants.max_framerate_fps) {
wants.max_framerate_fps = sink.wants.max_framerate_fps;
}
wants.resolution_alignment = cricket::LeastCommonMultiple(
wants.resolution_alignment, sink.wants.resolution_alignment);
// Pick MAX(requested_resolution) since the actual can be downscaled
// in encoder instead.
if (sink.wants.requested_resolution) {
if (!wants.requested_resolution) {
wants.requested_resolution = sink.wants.requested_resolution;
} else {
wants.requested_resolution->width =
std::max(wants.requested_resolution->width,
sink.wants.requested_resolution->width);
wants.requested_resolution->height =
std::max(wants.requested_resolution->height,
sink.wants.requested_resolution->height);
}
} else if (sink.wants.is_active) {
wants.aggregates->any_active_without_requested_resolution = true;
}
wants.is_active |= sink.wants.is_active;
}
if (wants.target_pixel_count &&
*wants.target_pixel_count >= wants.max_pixel_count) {
wants.target_pixel_count.emplace(wants.max_pixel_count);
}
current_wants_ = wants;
}
const rtc::scoped_refptr<webrtc::VideoFrameBuffer>&
VideoBroadcaster::GetBlackFrameBuffer(int width, int height) {
if (!black_frame_buffer_ || black_frame_buffer_->width() != width ||
black_frame_buffer_->height() != height) {
rtc::scoped_refptr<webrtc::I420Buffer> buffer =
webrtc::I420Buffer::Create(width, height);
webrtc::I420Buffer::SetBlack(buffer.get());
black_frame_buffer_ = buffer;
}
return black_frame_buffer_;
}
} // namespace rtc
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