зеркало из https://github.com/mozilla/gecko-dev.git
91 строка
3.0 KiB
C++
91 строка
3.0 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "VideoUtils.h"
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#include "MediaResource.h"
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#include "mozilla/dom/TimeRanges.h"
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#include "nsMathUtils.h"
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#include <stdint.h>
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// Converts from number of audio frames to microseconds, given the specified
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// audio rate.
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CheckedInt64 FramesToUsecs(int64_t aFrames, uint32_t aRate) {
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return (CheckedInt64(aFrames) * USECS_PER_S) / aRate;
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}
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// Converts from microseconds to number of audio frames, given the specified
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// audio rate.
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CheckedInt64 UsecsToFrames(int64_t aUsecs, uint32_t aRate) {
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return (CheckedInt64(aUsecs) * aRate) / USECS_PER_S;
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}
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static int32_t ConditionDimension(float aValue)
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{
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// This will exclude NaNs and too-big values.
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if (aValue > 1.0 && aValue <= INT32_MAX)
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return int32_t(NS_round(aValue));
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return 0;
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}
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void ScaleDisplayByAspectRatio(nsIntSize& aDisplay, float aAspectRatio)
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{
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if (aAspectRatio > 1.0) {
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// Increase the intrinsic width
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aDisplay.width = ConditionDimension(aAspectRatio * aDisplay.width);
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} else {
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// Increase the intrinsic height
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aDisplay.height = ConditionDimension(aDisplay.height / aAspectRatio);
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}
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}
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static int64_t BytesToTime(int64_t offset, int64_t length, int64_t durationUs) {
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NS_ASSERTION(length > 0, "Must have positive length");
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double r = double(offset) / double(length);
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if (r > 1.0)
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r = 1.0;
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return int64_t(double(durationUs) * r);
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}
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void GetEstimatedBufferedTimeRanges(mozilla::MediaResource* aStream,
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int64_t aDurationUsecs,
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mozilla::dom::TimeRanges* aOutBuffered)
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{
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// Nothing to cache if the media takes 0us to play.
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if (aDurationUsecs <= 0 || !aStream || !aOutBuffered)
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return;
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// Special case completely cached files. This also handles local files.
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if (aStream->IsDataCachedToEndOfResource(0)) {
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aOutBuffered->Add(0, double(aDurationUsecs) / USECS_PER_S);
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return;
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}
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int64_t totalBytes = aStream->GetLength();
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// If we can't determine the total size, pretend that we have nothing
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// buffered. This will put us in a state of eternally-low-on-undecoded-data
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// which is not great, but about the best we can do.
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if (totalBytes <= 0)
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return;
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int64_t startOffset = aStream->GetNextCachedData(0);
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while (startOffset >= 0) {
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int64_t endOffset = aStream->GetCachedDataEnd(startOffset);
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// Bytes [startOffset..endOffset] are cached.
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NS_ASSERTION(startOffset >= 0, "Integer underflow in GetBuffered");
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NS_ASSERTION(endOffset >= 0, "Integer underflow in GetBuffered");
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int64_t startUs = BytesToTime(startOffset, totalBytes, aDurationUsecs);
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int64_t endUs = BytesToTime(endOffset, totalBytes, aDurationUsecs);
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if (startUs != endUs) {
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aOutBuffered->Add(double(startUs) / USECS_PER_S,
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double(endUs) / USECS_PER_S);
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}
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startOffset = aStream->GetNextCachedData(endOffset);
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}
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return;
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}
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