gecko/content/media/VideoUtils.cpp

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2012-05-21 04:12:37 -07:00
/* 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 "VideoUtils.h"
#include "MediaResource.h"
#include "mozilla/dom/TimeRanges.h"
#include "nsMathUtils.h"
#include "nsSize.h"
#include "VorbisUtils.h"
#include <stdint.h>
namespace mozilla {
// Converts from number of audio frames to microseconds, given the specified
// audio rate.
CheckedInt64 FramesToUsecs(int64_t aFrames, uint32_t aRate) {
return (CheckedInt64(aFrames) * USECS_PER_S) / aRate;
}
// Converts from microseconds to number of audio frames, given the specified
// audio rate.
CheckedInt64 UsecsToFrames(int64_t aUsecs, uint32_t aRate) {
return (CheckedInt64(aUsecs) * aRate) / USECS_PER_S;
}
static int32_t ConditionDimension(float aValue)
{
// This will exclude NaNs and too-big values.
if (aValue > 1.0 && aValue <= INT32_MAX)
return int32_t(NS_round(aValue));
return 0;
}
void ScaleDisplayByAspectRatio(nsIntSize& aDisplay, float aAspectRatio)
{
if (aAspectRatio > 1.0) {
// Increase the intrinsic width
aDisplay.width = ConditionDimension(aAspectRatio * aDisplay.width);
} else {
// Increase the intrinsic height
aDisplay.height = ConditionDimension(aDisplay.height / aAspectRatio);
}
}
static int64_t BytesToTime(int64_t offset, int64_t length, int64_t durationUs) {
NS_ASSERTION(length > 0, "Must have positive length");
double r = double(offset) / double(length);
if (r > 1.0)
r = 1.0;
return int64_t(double(durationUs) * r);
}
void GetEstimatedBufferedTimeRanges(mozilla::MediaResource* aStream,
int64_t aDurationUsecs,
mozilla::dom::TimeRanges* aOutBuffered)
{
// Nothing to cache if the media takes 0us to play.
if (aDurationUsecs <= 0 || !aStream || !aOutBuffered)
return;
// Special case completely cached files. This also handles local files.
if (aStream->IsDataCachedToEndOfResource(0)) {
aOutBuffered->Add(0, double(aDurationUsecs) / USECS_PER_S);
return;
}
int64_t totalBytes = aStream->GetLength();
// If we can't determine the total size, pretend that we have nothing
// buffered. This will put us in a state of eternally-low-on-undecoded-data
// which is not great, but about the best we can do.
if (totalBytes <= 0)
return;
int64_t startOffset = aStream->GetNextCachedData(0);
while (startOffset >= 0) {
int64_t endOffset = aStream->GetCachedDataEnd(startOffset);
// Bytes [startOffset..endOffset] are cached.
NS_ASSERTION(startOffset >= 0, "Integer underflow in GetBuffered");
NS_ASSERTION(endOffset >= 0, "Integer underflow in GetBuffered");
int64_t startUs = BytesToTime(startOffset, totalBytes, aDurationUsecs);
int64_t endUs = BytesToTime(endOffset, totalBytes, aDurationUsecs);
if (startUs != endUs) {
aOutBuffered->Add(double(startUs) / USECS_PER_S,
double(endUs) / USECS_PER_S);
}
startOffset = aStream->GetNextCachedData(endOffset);
}
return;
}
int DownmixAudioToStereo(mozilla::AudioDataValue* buffer,
int channels, uint32_t frames)
{
int outChannels;
outChannels = 2;
#ifdef MOZ_SAMPLE_TYPE_FLOAT32
// Downmix matrix. Per-row normalization 1 for rows 3,4 and 2 for rows 5-8.
static const float dmatrix[6][8][2]= {
/*3*/{{0.5858f,0},{0.4142f,0.4142f},{0, 0.5858f}},
/*4*/{{0.4226f,0},{0, 0.4226f},{0.366f,0.2114f},{0.2114f,0.366f}},
/*5*/{{0.6510f,0},{0.4600f,0.4600f},{0, 0.6510f},{0.5636f,0.3254f},{0.3254f,0.5636f}},
/*6*/{{0.5290f,0},{0.3741f,0.3741f},{0, 0.5290f},{0.4582f,0.2645f},{0.2645f,0.4582f},{0.3741f,0.3741f}},
/*7*/{{0.4553f,0},{0.3220f,0.3220f},{0, 0.4553f},{0.3943f,0.2277f},{0.2277f,0.3943f},{0.2788f,0.2788f},{0.3220f,0.3220f}},
/*8*/{{0.3886f,0},{0.2748f,0.2748f},{0, 0.3886f},{0.3366f,0.1943f},{0.1943f,0.3366f},{0.3366f,0.1943f},{0.1943f,0.3366f},{0.2748f,0.2748f}},
};
// Re-write the buffer with downmixed data
for (uint32_t i = 0; i < frames; i++) {
float sampL = 0.0;
float sampR = 0.0;
for (int j = 0; j < channels; j++) {
sampL+=buffer[i*channels+j]*dmatrix[channels-3][j][0];
sampR+=buffer[i*channels+j]*dmatrix[channels-3][j][1];
}
buffer[i*outChannels]=sampL;
buffer[i*outChannels+1]=sampR;
}
#else
// Downmix matrix. Per-row normalization 1 for rows 3,4 and 2 for rows 5-8.
// Coefficients in Q14.
static const int16_t dmatrix[6][8][2]= {
/*3*/{{9598, 0},{6786,6786},{0, 9598}},
/*4*/{{6925, 0},{0, 6925},{5997,3462},{3462,5997}},
/*5*/{{10663,0},{7540,7540},{0, 10663},{9234,5331},{5331,9234}},
/*6*/{{8668, 0},{6129,6129},{0, 8668},{7507,4335},{4335,7507},{6129,6129}},
/*7*/{{7459, 0},{5275,5275},{0, 7459},{6460,3731},{3731,6460},{4568,4568},{5275,5275}},
/*8*/{{6368, 0},{4502,4502},{0, 6368},{5514,3184},{3184,5514},{5514,3184},{3184,5514},{4502,4502}}
};
// Re-write the buffer with downmixed data
for (uint32_t i = 0; i < frames; i++) {
int32_t sampL = 0;
int32_t sampR = 0;
for (int j = 0; j < channels; j++) {
sampL+=buffer[i*channels+j]*dmatrix[channels-3][j][0];
sampR+=buffer[i*channels+j]*dmatrix[channels-3][j][1];
}
sampL = (sampL + 8192)>>14;
buffer[i*outChannels] = static_cast<mozilla::AudioDataValue>(MOZ_CLIP_TO_15(sampL));
sampR = (sampR + 8192)>>14;
buffer[i*outChannels+1] = static_cast<mozilla::AudioDataValue>(MOZ_CLIP_TO_15(sampR));
}
#endif
return outChannels;
}
bool
IsVideoContentType(const nsCString& aContentType)
{
NS_NAMED_LITERAL_CSTRING(video, "video");
if (FindInReadable(video, aContentType)) {
return true;
}
return false;
}
} // end namespace mozilla