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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 MOZILLA_MEDIASEGMENT_H_
#define MOZILLA_MEDIASEGMENT_H_
#include "PrincipalHandle.h"
#include "nsTArray.h"
#ifdef MOZILLA_INTERNAL_API
# include "mozilla/TimeStamp.h"
#endif
#include <algorithm>
namespace mozilla {
/**
* Track or graph rate in Hz. Maximum 1 << TRACK_RATE_MAX_BITS Hz. This
* maximum avoids overflow in conversions between track rates and conversions
* from seconds.
*/
typedef int32_t TrackRate;
const int64_t TRACK_RATE_MAX_BITS = 20;
const TrackRate TRACK_RATE_MAX = 1 << TRACK_RATE_MAX_BITS;
/**
* A number of ticks at a rate determined by some underlying track (e.g., audio
* sample rate). We want to make sure that multiplying TrackTicks by a TrackRate
* doesn't overflow, so we set its max accordingly.
* TrackTime should be used instead when we're working with MediaTrackGraph's
* rate, but TrackTicks can be used outside MediaTracks when we have data at a
* different rate.
*/
typedef int64_t TrackTicks;
const int64_t TRACK_TICKS_MAX = INT64_MAX >> TRACK_RATE_MAX_BITS;
/**
* We represent media times in 64-bit audio frame counts or ticks.
* All tracks in a MediaTrackGraph have the same rate.
*/
typedef int64_t MediaTime;
const int64_t MEDIA_TIME_MAX = TRACK_TICKS_MAX;
/**
* Media time relative to the start of a MediaTrack.
*/
typedef MediaTime TrackTime;
const TrackTime TRACK_TIME_MAX = MEDIA_TIME_MAX;
/**
* Media time relative to the start of the graph timeline.
*/
typedef MediaTime GraphTime;
const GraphTime GRAPH_TIME_MAX = MEDIA_TIME_MAX;
/* Time conversion helper functions */
inline TrackTicks RateConvertTicksRoundDown(TrackRate aOutRate,
TrackRate aInRate,
TrackTicks aTicks) {
MOZ_ASSERT(0 < aOutRate && aOutRate <= TRACK_RATE_MAX, "Bad out rate");
MOZ_ASSERT(0 < aInRate && aInRate <= TRACK_RATE_MAX, "Bad in rate");
MOZ_ASSERT(0 <= aTicks && aTicks <= TRACK_TICKS_MAX, "Bad ticks");
return (aTicks * aOutRate) / aInRate;
}
inline TrackTicks RateConvertTicksRoundUp(TrackRate aOutRate, TrackRate aInRate,
TrackTicks aTicks) {
MOZ_ASSERT(0 < aOutRate && aOutRate <= TRACK_RATE_MAX, "Bad out rate");
MOZ_ASSERT(0 < aInRate && aInRate <= TRACK_RATE_MAX, "Bad in rate");
MOZ_ASSERT(0 <= aTicks && aTicks <= TRACK_TICKS_MAX, "Bad ticks");
return (aTicks * aOutRate + aInRate - 1) / aInRate;
}
/**
* The number of chunks allocated by default for a MediaSegment.
* Appending more chunks than this will cause further allocations.
*
* 16 is an arbitrary number intended to cover the most common cases in the
* MediaTrackGraph (1 with silence and 1-2 with data for a realtime track)
* with some margin.
*/
const size_t DEFAULT_SEGMENT_CAPACITY = 16;
/**
* A MediaSegment is a chunk of media data sequential in time. Different
* types of data have different subclasses of MediaSegment, all inheriting
* from MediaSegmentBase.
* All MediaSegment data is timed using TrackTime. The actual tick rate
* is defined on a per-track basis. For some track types, this can be
* a fixed constant for all tracks of that type (e.g. 1MHz for video).
*
* Each media segment defines a concept of "null media data" (e.g. silence
* for audio or "no video frame" for video), which can be efficiently
* represented. This is used for padding.
*/
class MediaSegment {
public:
MediaSegment(const MediaSegment&) = delete;
MediaSegment& operator=(const MediaSegment&) = delete;
MOZ_COUNTED_DTOR_VIRTUAL(MediaSegment)
enum Type { AUDIO, VIDEO, TYPE_COUNT };
/**
* Gets the total duration of the segment.
*/
TrackTime GetDuration() const { return mDuration; }
Type GetType() const { return mType; }
/**
* Gets the last principal id that was appended to this segment.
*/
const PrincipalHandle& GetLastPrincipalHandle() const {
return mLastPrincipalHandle;
}
/**
* Called by the MediaTrackGraph as it appends a chunk with a different
* principal id than the current one.
*/
void SetLastPrincipalHandle(PrincipalHandle aLastPrincipalHandle) {
mLastPrincipalHandle = std::forward<PrincipalHandle>(aLastPrincipalHandle);
}
/**
* Returns true if all chunks in this segment are null.
*/
virtual bool IsNull() const = 0;
/**
* Returns true if this segment contains no chunks.
*/
virtual bool IsEmpty() const = 0;
/**
* Create a MediaSegment of the same type.
*/
virtual MediaSegment* CreateEmptyClone() const = 0;
/**
* Moves contents of aSource to the end of this segment.
*/
virtual void AppendFrom(MediaSegment* aSource) = 0;
/**
* Append a slice of aSource to this segment.
*/
virtual void AppendSlice(const MediaSegment& aSource, TrackTime aStart,
TrackTime aEnd) = 0;
/**
* Replace all contents up to aDuration with null data.
*/
virtual void ForgetUpTo(TrackTime aDuration) = 0;
/**
* Forget all data buffered after a given point
*/
virtual void FlushAfter(TrackTime aNewEnd) = 0;
/**
* Insert aDuration of null data at the start of the segment.
*/
virtual void InsertNullDataAtStart(TrackTime aDuration) = 0;
/**
* Insert aDuration of null data at the end of the segment.
*/
virtual void AppendNullData(TrackTime aDuration) = 0;
/**
* Replace contents with disabled (silence/black) data of the same duration
*/
virtual void ReplaceWithDisabled() = 0;
/**
* Replace contents with null data of the same duration
*/
virtual void ReplaceWithNull() = 0;
/**
* Remove all contents, setting duration to 0.
*/
virtual void Clear() = 0;
virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
return 0;
}
virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
protected:
explicit MediaSegment(Type aType)
: mDuration(0),
mType(aType),
mLastPrincipalHandle(PRINCIPAL_HANDLE_NONE) {
MOZ_COUNT_CTOR(MediaSegment);
}
MediaSegment(MediaSegment&& aSegment)
: mDuration(std::move(aSegment.mDuration)),
mType(std::move(aSegment.mType)),
mLastPrincipalHandle(std::move(aSegment.mLastPrincipalHandle)) {
MOZ_COUNT_CTOR(MediaSegment);
}
TrackTime mDuration; // total of mDurations of all chunks
Type mType;
// The latest principal handle that the MediaTrackGraph has processed for
// this segment.
PrincipalHandle mLastPrincipalHandle;
};
/**
* C is the implementation class subclassed from MediaSegmentBase.
* C must contain a Chunk class.
*/
template <class C, class Chunk>
class MediaSegmentBase : public MediaSegment {
public:
bool IsNull() const override {
for (typename C::ConstChunkIterator iter(*this); !iter.IsEnded();
iter.Next()) {
if (!iter->IsNull()) {
return false;
}
}
return true;
}
bool IsEmpty() const override { return mChunks.IsEmpty(); }
MediaSegment* CreateEmptyClone() const override { return new C(); }
void AppendFrom(MediaSegment* aSource) override {
NS_ASSERTION(aSource->GetType() == C::StaticType(), "Wrong type");
AppendFromInternal(static_cast<C*>(aSource));
}
void AppendFrom(C* aSource) { AppendFromInternal(aSource); }
void AppendSlice(const MediaSegment& aSource, TrackTime aStart,
TrackTime aEnd) override {
NS_ASSERTION(aSource.GetType() == C::StaticType(), "Wrong type");
AppendSliceInternal(static_cast<const C&>(aSource), aStart, aEnd);
}
void AppendSlice(const C& aOther, TrackTime aStart, TrackTime aEnd) {
AppendSliceInternal(aOther, aStart, aEnd);
}
/**
* Replace the first aDuration ticks with null media data, because the data
* will not be required again.
*/
void ForgetUpTo(TrackTime aDuration) override {
if (mChunks.IsEmpty() || aDuration <= 0) {
return;
}
if (mChunks[0].IsNull()) {
TrackTime extraToForget =
std::min(aDuration, mDuration) - mChunks[0].GetDuration();
if (extraToForget > 0) {
RemoveLeading(extraToForget, 1);
mChunks[0].mDuration += extraToForget;
mDuration += extraToForget;
}
return;
}
RemoveLeading(aDuration, 0);
mChunks.InsertElementAt(0)->SetNull(aDuration);
mDuration += aDuration;
}
void FlushAfter(TrackTime aNewEnd) override {
if (mChunks.IsEmpty()) {
return;
}
if (!aNewEnd) {
Clear();
} else if (mChunks[0].IsNull()) {
TrackTime extraToKeep = aNewEnd - mChunks[0].GetDuration();
if (extraToKeep < 0) {
// reduce the size of the Null, get rid of everthing else
mChunks[0].SetNull(aNewEnd);
extraToKeep = 0;
}
RemoveTrailing(extraToKeep, 1);
} else {
if (aNewEnd > mDuration) {
NS_ASSERTION(aNewEnd <= mDuration, "can't add data in FlushAfter");
return;
}
RemoveTrailing(aNewEnd, 0);
}
mDuration = aNewEnd;
}
void InsertNullDataAtStart(TrackTime aDuration) override {
if (aDuration <= 0) {
return;
}
if (!mChunks.IsEmpty() && mChunks[0].IsNull()) {
mChunks[0].mDuration += aDuration;
} else {
mChunks.InsertElementAt(0)->SetNull(aDuration);
}
mDuration += aDuration;
}
void AppendNullData(TrackTime aDuration) override {
if (aDuration <= 0) {
return;
}
if (!mChunks.IsEmpty() && mChunks[mChunks.Length() - 1].IsNull()) {
mChunks[mChunks.Length() - 1].mDuration += aDuration;
} else {
mChunks.AppendElement()->SetNull(aDuration);
}
mDuration += aDuration;
}
void ReplaceWithDisabled() override {
if (GetType() != AUDIO) {
MOZ_CRASH("Disabling unknown segment type");
}
ReplaceWithNull();
}
void ReplaceWithNull() override {
TrackTime duration = GetDuration();
Clear();
AppendNullData(duration);
}
void Clear() override {
mDuration = 0;
mChunks.ClearAndRetainStorage();
mChunks.SetCapacity(DEFAULT_SEGMENT_CAPACITY);
}
class ChunkIterator {
public:
explicit ChunkIterator(MediaSegmentBase<C, Chunk>& aSegment)
: mSegment(aSegment), mIndex(0) {}
bool IsEnded() { return mIndex >= mSegment.mChunks.Length(); }
void Next() { ++mIndex; }
Chunk& operator*() { return mSegment.mChunks[mIndex]; }
Chunk* operator->() { return &mSegment.mChunks[mIndex]; }
private:
MediaSegmentBase<C, Chunk>& mSegment;
uint32_t mIndex;
};
class ConstChunkIterator {
public:
explicit ConstChunkIterator(const MediaSegmentBase<C, Chunk>& aSegment)
: mSegment(aSegment), mIndex(0) {}
bool IsEnded() { return mIndex >= mSegment.mChunks.Length(); }
void Next() { ++mIndex; }
const Chunk& operator*() { return mSegment.mChunks[mIndex]; }
const Chunk* operator->() { return &mSegment.mChunks[mIndex]; }
private:
const MediaSegmentBase<C, Chunk>& mSegment;
uint32_t mIndex;
};
void RemoveLeading(TrackTime aDuration) { RemoveLeading(aDuration, 0); }
size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const override {
size_t amount = mChunks.ShallowSizeOfExcludingThis(aMallocSizeOf);
for (size_t i = 0; i < mChunks.Length(); i++) {
amount += mChunks[i].SizeOfExcludingThisIfUnshared(aMallocSizeOf);
}
return amount;
}
size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override {
return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
}
Chunk* GetLastChunk() {
if (mChunks.IsEmpty()) {
return nullptr;
}
return &mChunks[mChunks.Length() - 1];
}
protected:
explicit MediaSegmentBase(Type aType) : MediaSegment(aType), mChunks() {}
MediaSegmentBase(MediaSegmentBase&& aSegment)
: MediaSegment(std::move(aSegment)),
mChunks(std::move(aSegment.mChunks)) {
MOZ_ASSERT(mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
"Capacity must be retained in self after swap");
MOZ_ASSERT(aSegment.mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
"Capacity must be retained in other after swap");
}
/**
* Appends the contents of aSource to this segment, clearing aSource.
*/
void AppendFromInternal(MediaSegmentBase<C, Chunk>* aSource) {
MOZ_ASSERT(aSource->mDuration >= 0);
mDuration += aSource->mDuration;
aSource->mDuration = 0;
size_t offset = 0;
if (!mChunks.IsEmpty() && !aSource->mChunks.IsEmpty() &&
mChunks[mChunks.Length() - 1].CanCombineWithFollowing(
aSource->mChunks[0])) {
mChunks[mChunks.Length() - 1].mDuration += aSource->mChunks[0].mDuration;
offset = 1;
}
for (; offset < aSource->mChunks.Length(); ++offset) {
mChunks.AppendElement(std::move(aSource->mChunks[offset]));
}
aSource->mChunks.ClearAndRetainStorage();
MOZ_ASSERT(aSource->mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
"Capacity must be retained after appending from aSource");
}
void AppendSliceInternal(const MediaSegmentBase<C, Chunk>& aSource,
TrackTime aStart, TrackTime aEnd) {
MOZ_ASSERT(aStart <= aEnd, "Endpoints inverted");
NS_ASSERTION(aStart >= 0 && aEnd <= aSource.mDuration,
"Slice out of range");
mDuration += aEnd - aStart;
TrackTime offset = 0;
for (uint32_t i = 0; i < aSource.mChunks.Length() && offset < aEnd; ++i) {
const Chunk& c = aSource.mChunks[i];
TrackTime start = std::max(aStart, offset);
TrackTime nextOffset = offset + c.GetDuration();
TrackTime end = std::min(aEnd, nextOffset);
if (start < end) {
if (!mChunks.IsEmpty() &&
mChunks[mChunks.Length() - 1].CanCombineWithFollowing(c)) {
MOZ_ASSERT(start - offset >= 0 && end - offset <= aSource.mDuration,
"Slice out of bounds");
mChunks[mChunks.Length() - 1].mDuration += end - start;
} else {
mChunks.AppendElement(c)->SliceTo(start - offset, end - offset);
}
}
offset = nextOffset;
}
}
Chunk* AppendChunk(TrackTime aDuration) {
MOZ_ASSERT(aDuration >= 0);
Chunk* c = mChunks.AppendElement();
c->mDuration = aDuration;
mDuration += aDuration;
return c;
}
void RemoveLeading(TrackTime aDuration, uint32_t aStartIndex) {
NS_ASSERTION(aDuration >= 0, "Can't remove negative duration");
TrackTime t = aDuration;
uint32_t chunksToRemove = 0;
for (uint32_t i = aStartIndex; i < mChunks.Length() && t > 0; ++i) {
Chunk* c = &mChunks[i];
if (c->GetDuration() > t) {
c->SliceTo(t, c->GetDuration());
t = 0;
break;
}
t -= c->GetDuration();
chunksToRemove = i + 1 - aStartIndex;
}
if (aStartIndex == 0 && chunksToRemove == mChunks.Length()) {
mChunks.ClearAndRetainStorage();
} else {
mChunks.RemoveElementsAt(aStartIndex, chunksToRemove);
}
mDuration -= aDuration - t;
MOZ_ASSERT(mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
"Capacity must be retained after removing chunks");
}
void RemoveTrailing(TrackTime aKeep, uint32_t aStartIndex) {
NS_ASSERTION(aKeep >= 0, "Can't keep negative duration");
TrackTime t = aKeep;
uint32_t i;
for (i = aStartIndex; i < mChunks.Length() && t; ++i) {
Chunk* c = &mChunks[i];
if (c->GetDuration() > t) {
c->SliceTo(0, t);
break;
}
t -= c->GetDuration();
}
// At this point `i` is already advanced due to last check in the loop.
if (i < mChunks.Length()) {
mChunks.RemoveLastElements(mChunks.Length() - i);
}
MOZ_ASSERT(mChunks.Capacity() >= DEFAULT_SEGMENT_CAPACITY,
"Capacity must be retained after removing chunks");
// Caller must adjust mDuration
}
AutoTArray<Chunk, DEFAULT_SEGMENT_CAPACITY> mChunks;
};
} // namespace mozilla
#endif /* MOZILLA_MEDIASEGMENT_H_ */