gecko-dev/dom/media/VideoUtils.h
2015-08-11 09:40:02 -04:00

302 lines
10 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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/. */
#ifndef VideoUtils_h
#define VideoUtils_h
#include "FlushableTaskQueue.h"
#include "mozilla/Attributes.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/MozPromise.h"
#include "mozilla/ReentrantMonitor.h"
#include "mozilla/RefPtr.h"
#include "nsIThread.h"
#include "nsSize.h"
#include "nsRect.h"
#include "nsThreadUtils.h"
#include "prtime.h"
#include "AudioSampleFormat.h"
#include "TimeUnits.h"
using mozilla::CheckedInt64;
using mozilla::CheckedUint64;
using mozilla::CheckedInt32;
using mozilla::CheckedUint32;
// This file contains stuff we'd rather put elsewhere, but which is
// dependent on other changes which we don't want to wait for. We plan to
// remove this file in the near future.
// This belongs in xpcom/monitor/Monitor.h, once we've made
// mozilla::Monitor non-reentrant.
namespace mozilla {
/**
* ReentrantMonitorConditionallyEnter
*
* Enters the supplied monitor only if the conditional value |aEnter| is true.
* E.g. Used to allow unmonitored read access on the decode thread,
* and monitored access on all other threads.
*/
class MOZ_STACK_CLASS ReentrantMonitorConditionallyEnter
{
public:
ReentrantMonitorConditionallyEnter(bool aEnter,
ReentrantMonitor &aReentrantMonitor) :
mReentrantMonitor(nullptr)
{
MOZ_COUNT_CTOR(ReentrantMonitorConditionallyEnter);
if (aEnter) {
mReentrantMonitor = &aReentrantMonitor;
NS_ASSERTION(mReentrantMonitor, "null monitor");
mReentrantMonitor->Enter();
}
}
~ReentrantMonitorConditionallyEnter(void)
{
if (mReentrantMonitor) {
mReentrantMonitor->Exit();
}
MOZ_COUNT_DTOR(ReentrantMonitorConditionallyEnter);
}
private:
// Restrict to constructor and destructor defined above.
ReentrantMonitorConditionallyEnter();
ReentrantMonitorConditionallyEnter(const ReentrantMonitorConditionallyEnter&);
ReentrantMonitorConditionallyEnter& operator =(const ReentrantMonitorConditionallyEnter&);
static void* operator new(size_t) CPP_THROW_NEW;
static void operator delete(void*);
ReentrantMonitor* mReentrantMonitor;
};
// Shuts down a thread asynchronously.
class ShutdownThreadEvent : public nsRunnable
{
public:
explicit ShutdownThreadEvent(nsIThread* aThread) : mThread(aThread) {}
~ShutdownThreadEvent() {}
NS_IMETHOD Run() override {
mThread->Shutdown();
mThread = nullptr;
return NS_OK;
}
private:
nsCOMPtr<nsIThread> mThread;
};
template<class T>
class DeleteObjectTask: public nsRunnable {
public:
explicit DeleteObjectTask(nsAutoPtr<T>& aObject)
: mObject(aObject)
{
}
NS_IMETHOD Run() {
NS_ASSERTION(NS_IsMainThread(), "Must be on main thread.");
mObject = nullptr;
return NS_OK;
}
private:
nsAutoPtr<T> mObject;
};
template<class T>
void DeleteOnMainThread(nsAutoPtr<T>& aObject) {
NS_DispatchToMainThread(new DeleteObjectTask<T>(aObject));
}
class MediaResource;
// Estimates the buffered ranges of a MediaResource using a simple
// (byteOffset/length)*duration method. Probably inaccurate, but won't
// do file I/O, and can be used when we don't have detailed knowledge
// of the byte->time mapping of a resource. aDurationUsecs is the duration
// of the media in microseconds. Estimated buffered ranges are stored in
// aOutBuffered. Ranges are 0-normalized, i.e. in the range of (0,duration].
media::TimeIntervals GetEstimatedBufferedTimeRanges(mozilla::MediaResource* aStream,
int64_t aDurationUsecs);
// Converts from number of audio frames (aFrames) to microseconds, given
// the specified audio rate (aRate).
CheckedInt64 FramesToUsecs(int64_t aFrames, uint32_t aRate);
// Converts from number of audio frames (aFrames) TimeUnit, given
// the specified audio rate (aRate).
media::TimeUnit FramesToTimeUnit(int64_t aFrames, uint32_t aRate);
// Converts from microseconds (aUsecs) to number of audio frames, given the
// specified audio rate (aRate). Stores the result in aOutFrames. Returns
// true if the operation succeeded, or false if there was an integer
// overflow while calulating the conversion.
CheckedInt64 UsecsToFrames(int64_t aUsecs, uint32_t aRate);
// Format TimeUnit as number of frames at given rate.
CheckedInt64 TimeUnitToFrames(const media::TimeUnit& aTime, uint32_t aRate);
// Converts milliseconds to seconds.
#define MS_TO_SECONDS(ms) ((double)(ms) / (PR_MSEC_PER_SEC))
// Converts seconds to milliseconds.
#define SECONDS_TO_MS(s) ((int)((s) * (PR_MSEC_PER_SEC)))
// Converts from seconds to microseconds. Returns failure if the resulting
// integer is too big to fit in an int64_t.
nsresult SecondsToUsecs(double aSeconds, int64_t& aOutUsecs);
// The maximum height and width of the video. Used for
// sanitizing the memory allocation of the RGB buffer.
// The maximum resolution we anticipate encountering in the
// wild is 2160p - 3840x2160 pixels.
static const int32_t MAX_VIDEO_WIDTH = 4000;
static const int32_t MAX_VIDEO_HEIGHT = 3000;
// Scales the display rect aDisplay by aspect ratio aAspectRatio.
// Note that aDisplay must be validated by IsValidVideoRegion()
// before being used!
void ScaleDisplayByAspectRatio(nsIntSize& aDisplay, float aAspectRatio);
// Downmix multichannel Audio samples to Stereo.
// Input are the buffer contains multichannel data,
// the number of channels and the number of frames.
int DownmixAudioToStereo(mozilla::AudioDataValue* buffer,
int channels,
uint32_t frames);
bool IsVideoContentType(const nsCString& aContentType);
// Returns true if it's safe to use aPicture as the picture to be
// extracted inside a frame of size aFrame, and scaled up to and displayed
// at a size of aDisplay. You should validate the frame, picture, and
// display regions before using them to display video frames.
bool IsValidVideoRegion(const nsIntSize& aFrame, const nsIntRect& aPicture,
const nsIntSize& aDisplay);
// Template to automatically set a variable to a value on scope exit.
// Useful for unsetting flags, etc.
template<typename T>
class AutoSetOnScopeExit {
public:
AutoSetOnScopeExit(T& aVar, T aValue)
: mVar(aVar)
, mValue(aValue)
{}
~AutoSetOnScopeExit() {
mVar = mValue;
}
private:
T& mVar;
const T mValue;
};
class SharedThreadPool;
// The MediaDataDecoder API blocks, with implementations waiting on platform
// decoder tasks. These platform decoder tasks are queued on a separate
// thread pool to ensure they can run when the MediaDataDecoder clients'
// thread pool is blocked. Tasks on the PLATFORM_DECODER thread pool must not
// wait on tasks in the PLAYBACK thread pool.
//
// No new dependencies on this mechanism should be added, as methods are being
// made async supported by MozPromise, making this unnecessary and
// permitting unifying the pool.
enum class MediaThreadType {
PLAYBACK, // MediaDecoderStateMachine and MediaDecoderReader
PLATFORM_DECODER
};
// Returns the thread pool that is shared amongst all decoder state machines
// for decoding streams.
already_AddRefed<SharedThreadPool> GetMediaThreadPool(MediaThreadType aType);
enum H264_PROFILE {
H264_PROFILE_UNKNOWN = 0,
H264_PROFILE_BASE = 0x42,
H264_PROFILE_MAIN = 0x4D,
H264_PROFILE_EXTENDED = 0x58,
H264_PROFILE_HIGH = 0x64,
};
enum H264_LEVEL {
H264_LEVEL_1 = 10,
H264_LEVEL_1_b = 11,
H264_LEVEL_1_1 = 11,
H264_LEVEL_1_2 = 12,
H264_LEVEL_1_3 = 13,
H264_LEVEL_2 = 20,
H264_LEVEL_2_1 = 21,
H264_LEVEL_2_2 = 22,
H264_LEVEL_3 = 30,
H264_LEVEL_3_1 = 31,
H264_LEVEL_3_2 = 32,
H264_LEVEL_4 = 40,
H264_LEVEL_4_1 = 41,
H264_LEVEL_4_2 = 42,
H264_LEVEL_5 = 50,
H264_LEVEL_5_1 = 51,
H264_LEVEL_5_2 = 52
};
// Extracts the H.264/AVC profile and level from an H.264 codecs string.
// H.264 codecs parameters have a type defined as avc1.PPCCLL, where
// PP = profile_idc, CC = constraint_set flags, LL = level_idc.
// See http://blog.pearce.org.nz/2013/11/what-does-h264avc1-codecs-parameters.html
// for more details.
// Returns false on failure.
bool
ExtractH264CodecDetails(const nsAString& aCodecs,
int16_t& aProfile,
int16_t& aLevel);
// Use a cryptographic quality PRNG to generate raw random bytes
// and convert that to a base64 string.
nsresult
GenerateRandomName(nsCString& aOutSalt, uint32_t aLength);
// This version returns a string suitable for use as a file or URL
// path. This is based on code from nsExternalAppHandler::SetUpTempFile.
nsresult
GenerateRandomPathName(nsCString& aOutSalt, uint32_t aLength);
already_AddRefed<TaskQueue>
CreateMediaDecodeTaskQueue();
already_AddRefed<FlushableTaskQueue>
CreateFlushableMediaDecodeTaskQueue();
// Iteratively invokes aWork until aCondition returns true, or aWork returns false.
// Use this rather than a while loop to avoid bogarting the task queue.
template<class Work, class Condition>
nsRefPtr<GenericPromise> InvokeUntil(Work aWork, Condition aCondition) {
nsRefPtr<GenericPromise::Private> p = new GenericPromise::Private(__func__);
if (aCondition()) {
p->Resolve(true, __func__);
}
struct Helper {
static void Iteration(nsRefPtr<GenericPromise::Private> aPromise, Work aWork, Condition aCondition) {
if (!aWork()) {
aPromise->Reject(NS_ERROR_FAILURE, __func__);
} else if (aCondition()) {
aPromise->Resolve(true, __func__);
} else {
nsCOMPtr<nsIRunnable> r =
NS_NewRunnableFunction([aPromise, aWork, aCondition] () { Iteration(aPromise, aWork, aCondition); });
AbstractThread::GetCurrent()->Dispatch(r.forget());
}
}
};
Helper::Iteration(p, aWork, aCondition);
return p.forget();
}
} // end namespace mozilla
#endif