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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /gfx/layers/composite/ImageComposite.cpp
parentInitial commit. (diff)
downloadfirefox-upstream/124.0.1.tar.xz
firefox-upstream/124.0.1.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'gfx/layers/composite/ImageComposite.cpp')
-rw-r--r--gfx/layers/composite/ImageComposite.cpp378
1 files changed, 378 insertions, 0 deletions
diff --git a/gfx/layers/composite/ImageComposite.cpp b/gfx/layers/composite/ImageComposite.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ImageComposite.h"
+
+#include <inttypes.h>
+
+#include "mozilla/ProfilerMarkers.h"
+#include "gfxPlatform.h"
+#include "nsPrintfCString.h"
+
+namespace mozilla {
+
+using namespace gfx;
+
+namespace layers {
+
+/* static */ const float ImageComposite::BIAS_TIME_MS = 1.0f;
+
+ImageComposite::ImageComposite() = default;
+
+ImageComposite::~ImageComposite() = default;
+
+TimeStamp ImageComposite::GetBiasedTime(const TimeStamp& aInput) const {
+ switch (mBias) {
+ case ImageComposite::BIAS_NEGATIVE:
+ return aInput - TimeDuration::FromMilliseconds(BIAS_TIME_MS);
+ case ImageComposite::BIAS_POSITIVE:
+ return aInput + TimeDuration::FromMilliseconds(BIAS_TIME_MS);
+ default:
+ return aInput;
+ }
+}
+
+void ImageComposite::UpdateBias(size_t aImageIndex, bool aFrameChanged) {
+ MOZ_ASSERT(aImageIndex < ImagesCount());
+
+ TimeStamp compositionTime = GetCompositionTime();
+ TimeStamp compositedImageTime = mImages[aImageIndex].mTimeStamp;
+ TimeStamp nextImageTime = aImageIndex + 1 < ImagesCount()
+ ? mImages[aImageIndex + 1].mTimeStamp
+ : TimeStamp();
+
+ if (profiler_thread_is_being_profiled_for_markers() && compositedImageTime &&
+ nextImageTime) {
+ TimeDuration offsetCurrent = compositedImageTime - compositionTime;
+ TimeDuration offsetNext = nextImageTime - compositionTime;
+ nsPrintfCString str("current %.2lfms, next %.2lfms",
+ offsetCurrent.ToMilliseconds(),
+ offsetNext.ToMilliseconds());
+ PROFILER_MARKER_TEXT("Video frame offsets", GRAPHICS, {}, str);
+ }
+
+ if (compositedImageTime.IsNull()) {
+ mBias = ImageComposite::BIAS_NONE;
+ return;
+ }
+ TimeDuration threshold = TimeDuration::FromMilliseconds(1.5);
+ if (compositionTime - compositedImageTime < threshold &&
+ compositionTime - compositedImageTime > -threshold) {
+ // The chosen frame's time is very close to the composition time (probably
+ // just before the current composition time, but due to previously set
+ // negative bias, it could be just after the current composition time too).
+ // If the inter-frame time is almost exactly equal to (a multiple of)
+ // the inter-composition time, then we're in a dangerous situation because
+ // jitter might cause frames to fall one side or the other of the
+ // composition times, causing many frames to be skipped or duplicated.
+ // Try to prevent that by adding a negative bias to the frame times during
+ // the next composite; that should ensure the next frame's time is treated
+ // as falling just before a composite time.
+ mBias = ImageComposite::BIAS_NEGATIVE;
+ return;
+ }
+ if (!nextImageTime.IsNull() && nextImageTime - compositionTime < threshold &&
+ nextImageTime - compositionTime > -threshold) {
+ // The next frame's time is very close to our composition time (probably
+ // just after the current composition time, but due to previously set
+ // positive bias, it could be just before the current composition time too).
+ // We're in a dangerous situation because jitter might cause frames to
+ // fall one side or the other of the composition times, causing many frames
+ // to be skipped or duplicated.
+ // Specifically, the next composite is at risk of picking the "next + 1"
+ // frame rather than the "next" frame, which would cause the "next" frame to
+ // be skipped. Try to prevent that by adding a positive bias to the frame
+ // times during the next composite; if the inter-frame time is almost
+ // exactly equal to the inter-composition time, that should ensure that the
+ // next + 1 frame falls just *after* the next composition time, and the next
+ // composite should then pick the next frame rather than the next + 1 frame.
+ mBias = ImageComposite::BIAS_POSITIVE;
+ return;
+ }
+ if (aFrameChanged) {
+ // The current and next video frames are a sufficient distance from the
+ // composition time and we can reliably pick the right frame without bias.
+ // Reset the bias.
+ // We only do this when the frame changed. Otherwise, when playing a 30fps
+ // video on a 60fps display, we'd keep resetting the bias during the "middle
+ // frames".
+ mBias = ImageComposite::BIAS_NONE;
+ }
+}
+
+int ImageComposite::ChooseImageIndex() {
+ // ChooseImageIndex is called for all images in the layer when it is visible.
+ // Change to this behaviour would break dropped frames counting calculation:
+ // We rely on this assumption to determine if during successive runs an
+ // image is returned that isn't the one following immediately the previous one
+ if (mImages.IsEmpty()) {
+ return -1;
+ }
+
+ TimeStamp compositionTime = GetCompositionTime();
+ auto compositionOpportunityId = GetCompositionOpportunityId();
+ if (compositionTime &&
+ compositionOpportunityId != mLastChooseImageIndexComposition) {
+ // We are inside a composition, in the first call to ChooseImageIndex during
+ // this composition.
+ // Find the newest frame whose biased timestamp is at or before
+ // `compositionTime`.
+ uint32_t imageIndex = 0;
+ while (imageIndex + 1 < mImages.Length() &&
+ mImages[imageIndex + 1].mTextureHost->IsValid() &&
+ GetBiasedTime(mImages[imageIndex + 1].mTimeStamp) <=
+ compositionTime) {
+ ++imageIndex;
+ }
+
+ if (!mImages[imageIndex].mTextureHost->IsValid()) {
+ // Still not ready to be shown.
+ return -1;
+ }
+
+ bool wasVisibleAtPreviousComposition =
+ compositionOpportunityId == mLastChooseImageIndexComposition.Next();
+
+ bool frameChanged =
+ UpdateCompositedFrame(imageIndex, wasVisibleAtPreviousComposition);
+ UpdateBias(imageIndex, frameChanged);
+
+ mLastChooseImageIndexComposition = compositionOpportunityId;
+
+ return imageIndex;
+ }
+
+ // We've been called before during this composition, or we're not in a
+ // composition. Just return the last image we picked (if it's one of the
+ // current images).
+ for (uint32_t i = 0; i < mImages.Length(); ++i) {
+ if (mImages[i].mFrameID == mLastFrameID &&
+ mImages[i].mProducerID == mLastProducerID) {
+ return i;
+ }
+ }
+
+ return 0;
+}
+
+const ImageComposite::TimedImage* ImageComposite::ChooseImage() {
+ int index = ChooseImageIndex();
+ return index >= 0 ? &mImages[index] : nullptr;
+}
+
+void ImageComposite::RemoveImagesWithTextureHost(TextureHost* aTexture) {
+ for (int32_t i = mImages.Length() - 1; i >= 0; --i) {
+ if (mImages[i].mTextureHost == aTexture) {
+ aTexture->UnbindTextureSource();
+ mImages.RemoveElementAt(i);
+ }
+ }
+}
+
+void ImageComposite::ClearImages() { mImages.Clear(); }
+
+void ImageComposite::SetImages(nsTArray<TimedImage>&& aNewImages) {
+ if (!aNewImages.IsEmpty()) {
+ DetectTimeStampJitter(&aNewImages[0]);
+
+ // Frames older than the first frame in aNewImages that we haven't shown yet
+ // will never be shown.
+ CountSkippedFrames(&aNewImages[0]);
+
+ if (profiler_thread_is_being_profiled_for_markers()) {
+ int len = aNewImages.Length();
+ const auto& first = aNewImages[0];
+ const auto& last = aNewImages.LastElement();
+ nsPrintfCString str("%d %s, frameID %" PRId32 " (prod %" PRId32
+ ") to frameID %" PRId32 " (prod %" PRId32 ")",
+ len, len == 1 ? "image" : "images", first.mFrameID,
+ first.mProducerID, last.mFrameID, last.mProducerID);
+ PROFILER_MARKER_TEXT("ImageComposite::SetImages", GRAPHICS, {}, str);
+ }
+ }
+ mImages = std::move(aNewImages);
+}
+
+// Returns whether the frame changed.
+bool ImageComposite::UpdateCompositedFrame(
+ int aImageIndex, bool aWasVisibleAtPreviousComposition) {
+ MOZ_RELEASE_ASSERT(aImageIndex >= 0);
+ MOZ_RELEASE_ASSERT(aImageIndex < static_cast<int>(mImages.Length()));
+ const TimedImage& image = mImages[aImageIndex];
+
+ auto compositionOpportunityId = GetCompositionOpportunityId();
+ TimeStamp compositionTime = GetCompositionTime();
+ MOZ_RELEASE_ASSERT(compositionTime,
+ "Should only be called during a composition");
+
+ nsCString descr;
+ if (profiler_thread_is_being_profiled_for_markers()) {
+ nsCString relativeTimeString;
+ if (image.mTimeStamp) {
+ relativeTimeString.AppendPrintf(
+ " [relative timestamp %.1lfms]",
+ (image.mTimeStamp - compositionTime).ToMilliseconds());
+ }
+ int remainingImages = mImages.Length() - 1 - aImageIndex;
+ static const char* kBiasStrings[] = {"NONE", "NEGATIVE", "POSITIVE"};
+ descr.AppendPrintf(
+ "frameID %" PRId32 " (producerID %" PRId32 ") [composite %" PRIu64
+ "] [bias %s] [%d remaining %s]%s",
+ image.mFrameID, image.mProducerID, compositionOpportunityId.mId,
+ kBiasStrings[mBias], remainingImages,
+ remainingImages == 1 ? "image" : "images", relativeTimeString.get());
+ if (mLastProducerID != image.mProducerID) {
+ descr.AppendPrintf(", previous producerID: %" PRId32, mLastProducerID);
+ } else if (mLastFrameID != image.mFrameID) {
+ descr.AppendPrintf(", previous frameID: %" PRId32, mLastFrameID);
+ } else {
+ descr.AppendLiteral(", no change");
+ }
+ }
+ PROFILER_MARKER_TEXT("UpdateCompositedFrame", GRAPHICS, {}, descr);
+
+ if (mLastFrameID == image.mFrameID && mLastProducerID == image.mProducerID) {
+ // The frame didn't change.
+ return false;
+ }
+
+ CountSkippedFrames(&image);
+
+ int32_t dropped = mSkippedFramesSinceLastComposite;
+ mSkippedFramesSinceLastComposite = 0;
+
+ if (!aWasVisibleAtPreviousComposition) {
+ // This video was not part of the on-screen scene during the previous
+ // composition opportunity, for example it may have been scrolled off-screen
+ // or in a background tab, or compositing might have been paused.
+ // Ignore any skipped frames and don't count them as dropped.
+ dropped = 0;
+ }
+
+ if (dropped > 0) {
+ mDroppedFrames += dropped;
+ if (profiler_thread_is_being_profiled_for_markers()) {
+ const char* frameOrFrames = dropped == 1 ? "frame" : "frames";
+ nsPrintfCString text("%" PRId32 " %s dropped: %" PRId32 " -> %" PRId32
+ " (producer %" PRId32 ")",
+ dropped, frameOrFrames, mLastFrameID, image.mFrameID,
+ mLastProducerID);
+ PROFILER_MARKER_TEXT("Video frames dropped", GRAPHICS, {}, text);
+ }
+ }
+
+ mLastFrameID = image.mFrameID;
+ mLastProducerID = image.mProducerID;
+ mLastFrameUpdateComposition = compositionOpportunityId;
+
+ return true;
+}
+
+void ImageComposite::OnFinishRendering(int aImageIndex,
+ const TimedImage* aImage,
+ base::ProcessId aProcessId,
+ const CompositableHandle& aHandle) {
+ if (mLastFrameUpdateComposition != GetCompositionOpportunityId()) {
+ // The frame did not change in this composition.
+ return;
+ }
+
+ if (aHandle) {
+ ImageCompositeNotificationInfo info;
+ info.mImageBridgeProcessId = aProcessId;
+ info.mNotification = ImageCompositeNotification(
+ aHandle, aImage->mTimeStamp, GetCompositionTime(), mLastFrameID,
+ mLastProducerID);
+ AppendImageCompositeNotification(info);
+ }
+}
+
+const ImageComposite::TimedImage* ImageComposite::GetImage(
+ size_t aIndex) const {
+ if (aIndex >= mImages.Length()) {
+ return nullptr;
+ }
+ return &mImages[aIndex];
+}
+
+void ImageComposite::CountSkippedFrames(const TimedImage* aImage) {
+ if (aImage->mProducerID != mLastProducerID) {
+ // Switched producers.
+ return;
+ }
+
+ if (mImages.IsEmpty() || aImage->mFrameID <= mLastFrameID + 1) {
+ // No frames were skipped.
+ return;
+ }
+
+ uint32_t targetFrameRate = gfxPlatform::TargetFrameRate();
+ if (targetFrameRate == 0) {
+ // Can't know whether we could have reasonably displayed all video frames.
+ return;
+ }
+
+ double targetFrameDurationMS = 1000.0 / targetFrameRate;
+
+ // Count how many images in mImages were skipped between mLastFrameID and
+ // aImage.mFrameID. Only count frames for which we can estimate a duration by
+ // looking at the next frame's timestamp, and only if the video frame rate is
+ // no faster than the target frame rate.
+ int32_t skipped = 0;
+ for (size_t i = 0; i + 1 < mImages.Length(); i++) {
+ const auto& img = mImages[i];
+ if (img.mProducerID != aImage->mProducerID ||
+ img.mFrameID <= mLastFrameID || img.mFrameID >= aImage->mFrameID) {
+ continue;
+ }
+
+ // We skipped img! Estimate img's time duration.
+ const auto& next = mImages[i + 1];
+ if (next.mProducerID != aImage->mProducerID) {
+ continue;
+ }
+
+ MOZ_ASSERT(next.mFrameID > img.mFrameID);
+ TimeDuration duration = next.mTimeStamp - img.mTimeStamp;
+ if (floor(duration.ToMilliseconds()) >= floor(targetFrameDurationMS)) {
+ // Count the frame.
+ skipped++;
+ }
+ }
+
+ mSkippedFramesSinceLastComposite += skipped;
+}
+
+void ImageComposite::DetectTimeStampJitter(const TimedImage* aNewImage) {
+ if (!profiler_thread_is_being_profiled_for_markers() ||
+ aNewImage->mTimeStamp.IsNull()) {
+ return;
+ }
+
+ // Find aNewImage in mImages and compute its timestamp delta, if found.
+ // Ideally, a given video frame should never change its timestamp (jitter
+ // should be zero). However, we re-adjust video frame timestamps based on the
+ // audio clock. If the audio clock drifts compared to the system clock, or if
+ // there are bugs or inaccuracies in the computation of these timestamps,
+ // jitter will be non-zero.
+ Maybe<TimeDuration> jitter;
+ for (const auto& img : mImages) {
+ if (img.mProducerID == aNewImage->mProducerID &&
+ img.mFrameID == aNewImage->mFrameID) {
+ if (!img.mTimeStamp.IsNull()) {
+ jitter = Some(aNewImage->mTimeStamp - img.mTimeStamp);
+ }
+ break;
+ }
+ }
+ if (jitter) {
+ nsPrintfCString text("%.2lfms", jitter->ToMilliseconds());
+ PROFILER_MARKER_TEXT("VideoFrameTimeStampJitter", GRAPHICS, {}, text);
+ }
+}
+
+} // namespace layers
+} // namespace mozilla