Motown: Video renderer library code

mojo/services/media/common/cpp/video_renderer.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <limits>
+
+#include "mojo/services/media/common/cpp/timeline.h"
+#include "mojo/services/media/common/cpp/video_renderer.h"
+
+namespace mojo {
+namespace media {
+
+VideoRenderer::VideoRenderer()
+    : renderer_binding_(this),
+      consumer_binding_(this),
+      control_site_binding_(this),
+      timeline_consumer_binding_(this) {}
+
+VideoRenderer::~VideoRenderer() {}
+
+void VideoRenderer::Bind(InterfaceRequest<MediaRenderer> renderer_request) {
+  renderer_binding_.Bind(renderer_request.Pass());
+}
+
+void VideoRenderer::GetRgbaFrame(uint8_t* rgba_buffer,
+                                 size_t width,
+                                 size_t height,
+                                 int64_t reference_time) {
+  MaybeApplyPendingTimelineChange(reference_time);
+  MaybePublishEndOfStream();
+
+  int64_t presentation_time = current_timeline_function_(reference_time);
+
+  // Discard empty and old packets. We keep one packet around even if it's old,
+  // so we can show an old frame instead of no frame when we starve.
+  while (!packet_queue_.empty() &&
+         (!packet_queue_.front().packet_->payload ||
+          packet_queue_.front().packet_->payload->length == 0 ||
+          (packet_queue_.size() > 1 &&
+           packet_queue_.front().packet_->pts < presentation_time))) {
+    // TODO(dalesat): Add hysteresis.
+    packet_queue_.pop();
+  }
+
+  // TODO(dalesat): Detect starvation.
+
+  if (packet_queue_.empty()) {
+    memset(rgba_buffer, 0, width * height * 4);
+  } else {
+    const MediaPacketPtr& packet = packet_queue_.front().packet_;
+    converter_.ConvertFrame(
+        rgba_buffer, width, height,
+        shared_buffer_.PtrFromOffset(packet->payload->offset),
+        packet->payload->length);
+  }
+}
+
+void VideoRenderer::GetSupportedMediaTypes(
+    const GetSupportedMediaTypesCallback& callback) {
+  VideoMediaTypeSetDetailsPtr video_details = VideoMediaTypeSetDetails::New();
+  video_details->min_width = 1;
+  video_details->max_width = std::numeric_limits<uint32_t>::max();
+  video_details->min_height = 1;
+  video_details->max_height = std::numeric_limits<uint32_t>::max();
+  MediaTypeSetPtr supported_type = MediaTypeSet::New();
+  supported_type->medium = MediaTypeMedium::VIDEO;
+  supported_type->details = MediaTypeSetDetails::New();
+  supported_type->details->set_video(video_details.Pass());
+  supported_type->encodings = Array<String>::New(1);
+  supported_type->encodings[0] = MediaType::kVideoEncodingUncompressed;
+  Array<MediaTypeSetPtr> supported_types = Array<MediaTypeSetPtr>::New(1);
+  supported_types[0] = supported_type.Pass();
+  callback.Run(supported_types.Pass());
+}
+
+void VideoRenderer::SetMediaType(MediaTypePtr media_type) {
+  MOJO_DCHECK(media_type);
+  MOJO_DCHECK(media_type->details);
+  const VideoMediaTypeDetailsPtr& details = media_type->details->get_video();
+  MOJO_DCHECK(details);
+
+  converter_.SetMediaType(media_type);
+}
+
+void VideoRenderer::GetConsumer(
+    InterfaceRequest<MediaConsumer> consumer_request) {
+  consumer_binding_.Bind(consumer_request.Pass());
+}
+
+void VideoRenderer::GetTimelineControlSite(
+    InterfaceRequest<MediaTimelineControlSite> control_site_request) {
+  control_site_binding_.Bind(control_site_request.Pass());
+}
+
+void VideoRenderer::SetBuffer(ScopedSharedBufferHandle buffer,
+                              const SetBufferCallback& callback) {
+  shared_buffer_.InitFromHandle(buffer.Pass());
+  callback.Run();
+}
+
+void VideoRenderer::SendPacket(MediaPacketPtr packet,
+                               const SendPacketCallback& callback) {
+  MOJO_DCHECK(packet);
+  if (packet->end_of_stream) {
+    MOJO_DLOG(INFO) << "END_OF_STREAM";
+    end_of_stream_pts_ = packet->pts;
+  }
+
+  packet_queue_.emplace(packet.Pass(), callback);
+}
+
+void VideoRenderer::Prime(const PrimeCallback& callback) {
+  callback.Run();
+}
+
+void VideoRenderer::Flush(const FlushCallback& callback) {
+  while (!packet_queue_.empty()) {
+    packet_queue_.pop();
+  }
+  callback.Run();
+}
+
+void VideoRenderer::GetStatus(uint64_t version_last_seen,
+                              const GetStatusCallback& callback) {
+  if (version_last_seen < status_version_) {
+    CompleteGetStatus(callback);
+  } else {
+    pending_status_callbacks_.push_back(callback);
+  }
+}
+
+void VideoRenderer::GetTimelineConsumer(
+    InterfaceRequest<TimelineConsumer> timeline_consumer_request) {
+  timeline_consumer_binding_.Bind(timeline_consumer_request.Pass());
+}
+
+void VideoRenderer::SetTimelineTransform(
+    int64_t subject_time,
+    uint32_t reference_delta,
+    uint32_t subject_delta,
+    int64_t effective_reference_time,
+    int64_t effective_subject_time,
+    const SetTimelineTransformCallback& callback) {
+  // At most one of the effective times must be specified.
+  MOJO_DCHECK(effective_reference_time == kUnspecifiedTime ||
+              effective_subject_time == kUnspecifiedTime);
+  // effective_subject_time can only be used if we're progressing already.
+  MOJO_DCHECK(effective_subject_time == kUnspecifiedTime ||
+              current_timeline_function_.subject_delta() != 0);
+  MOJO_DCHECK(reference_delta != 0);
+
+  if (subject_time != kUnspecifiedTime &&
+      end_of_stream_pts_ != kUnspecifiedTime) {
+    end_of_stream_pts_ = kUnspecifiedTime;
+    end_of_stream_published_ = false;
+  }
+
+  if (effective_subject_time != kUnspecifiedTime) {
+    // Infer effective_reference_time from effective_subject_time.
+    effective_reference_time =
+        current_timeline_function_.ApplyInverse(effective_subject_time);
+
+    if (subject_time == kUnspecifiedTime) {
+      // Infer subject_time from effective_subject_time.
+      subject_time = effective_subject_time;
+    }
+  } else {
+    if (effective_reference_time == kUnspecifiedTime) {
+      // Neither effective time was specified. Effective time is now.
+      effective_reference_time = Timeline::local_now();
+    }
+
+    if (subject_time == kUnspecifiedTime) {
+      // Infer subject_time from effective_reference_time.
+      subject_time = current_timeline_function_(effective_reference_time);
+    }
+  }
+
+  // Eject any previous pending change.
+  ClearPendingTimelineFunction(false);
+
+  // Queue up the new pending change.
+  pending_timeline_function_ = TimelineFunction(
+      effective_reference_time, subject_time, reference_delta, subject_delta);
+
+  set_timeline_transform_callback_ = callback;
+}
+
+void VideoRenderer::ClearPendingTimelineFunction(bool completed) {
+  pending_timeline_function_ =
+      TimelineFunction(kUnspecifiedTime, kUnspecifiedTime, 1, 0);
+  if (!set_timeline_transform_callback_.is_null()) {
+    set_timeline_transform_callback_.Run(completed);
+    set_timeline_transform_callback_.reset();
+  }
+}
+
+void VideoRenderer::MaybeApplyPendingTimelineChange(int64_t reference_time) {
+  if (pending_timeline_function_.reference_time() == kUnspecifiedTime ||
+      pending_timeline_function_.reference_time() > reference_time) {
+    return;
+  }
+
+  current_timeline_function_ = pending_timeline_function_;
+  pending_timeline_function_ =
+      TimelineFunction(kUnspecifiedTime, kUnspecifiedTime, 1, 0);
+
+  if (!set_timeline_transform_callback_.is_null()) {
+    set_timeline_transform_callback_.Run(true);
+    set_timeline_transform_callback_.reset();
+  }
+
+  SendStatusUpdates();
+}
+
+void VideoRenderer::MaybePublishEndOfStream() {
+  if (!end_of_stream_published_ && end_of_stream_pts_ != kUnspecifiedTime &&
+      current_timeline_function_(Timeline::local_now()) >= end_of_stream_pts_) {
+    end_of_stream_published_ = true;
+    SendStatusUpdates();
+  }
+}
+
+void VideoRenderer::SendStatusUpdates() {
+  ++status_version_;
+
+  std::vector<GetStatusCallback> pending_status_callbacks;
+  pending_status_callbacks_.swap(pending_status_callbacks);
+
+  for (const GetStatusCallback& pending_status_callback :
+       pending_status_callbacks) {
+    CompleteGetStatus(pending_status_callback);
+  }
+}
+
+void VideoRenderer::CompleteGetStatus(const GetStatusCallback& callback) {
+  MediaTimelineControlSiteStatusPtr status =
+      MediaTimelineControlSiteStatus::New();
+  status->timeline_transform =
+      TimelineTransform::From(current_timeline_function_);
+  status->end_of_stream =
+      end_of_stream_pts_ != kUnspecifiedTime &&
+      current_timeline_function_(Timeline::local_now()) >= end_of_stream_pts_;
+  callback.Run(status_version_, status.Pass());
+}
+
+VideoRenderer::PacketAndCallback::PacketAndCallback(
+    MediaPacketPtr packet,
+    const SendPacketCallback& callback)
+    : packet_(packet.Pass()), callback_(callback) {
+  MOJO_DCHECK(packet_);
+  MOJO_DCHECK(!callback.is_null());
+}
+
+VideoRenderer::PacketAndCallback::~PacketAndCallback() {
+  callback_.Run(MediaConsumer::SendResult::CONSUMED);
+}
+
+}  // namespace media
+}  // namespace mojo