1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/media/MediaSegment.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,374 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.7 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef MOZILLA_MEDIASEGMENT_H_
1.10 +#define MOZILLA_MEDIASEGMENT_H_
1.11 +
1.12 +#include "nsTArray.h"
1.13 +#ifdef MOZILLA_INTERNAL_API
1.14 +#include "mozilla/TimeStamp.h"
1.15 +#endif
1.16 +#include <algorithm>
1.17 +#include "Latency.h"
1.18 +
1.19 +namespace mozilla {
1.20 +
1.21 +/**
1.22 + * We represent media times in 64-bit fixed point. So 1 MediaTime is
1.23 + * 1/(2^MEDIA_TIME_FRAC_BITS) seconds.
1.24 + */
1.25 +typedef int64_t MediaTime;
1.26 +const int64_t MEDIA_TIME_FRAC_BITS = 20;
1.27 +const int64_t MEDIA_TIME_MAX = INT64_MAX;
1.28 +
1.29 +inline MediaTime MillisecondsToMediaTime(int32_t aMS)
1.30 +{
1.31 + return (MediaTime(aMS) << MEDIA_TIME_FRAC_BITS)/1000;
1.32 +}
1.33 +
1.34 +inline MediaTime SecondsToMediaTime(double aS)
1.35 +{
1.36 + NS_ASSERTION(aS <= (MEDIA_TIME_MAX >> MEDIA_TIME_FRAC_BITS),
1.37 + "Out of range");
1.38 + return MediaTime(aS * (1 << MEDIA_TIME_FRAC_BITS));
1.39 +}
1.40 +
1.41 +inline double MediaTimeToSeconds(MediaTime aTime)
1.42 +{
1.43 + return aTime*(1.0/(1 << MEDIA_TIME_FRAC_BITS));
1.44 +}
1.45 +
1.46 +inline int64_t MediaTimeToMicroseconds(MediaTime aTime)
1.47 +{
1.48 + return aTime*(1000000.0/(1 << MEDIA_TIME_FRAC_BITS));
1.49 +}
1.50 +
1.51 +/**
1.52 + * A number of ticks at a rate determined by some underlying track (e.g.
1.53 + * audio sample rate). We want to make sure that multiplying TrackTicks by
1.54 + * 2^MEDIA_TIME_FRAC_BITS doesn't overflow, so we set its max accordingly.
1.55 + */
1.56 +typedef int64_t TrackTicks;
1.57 +const int64_t TRACK_TICKS_MAX = INT64_MAX >> MEDIA_TIME_FRAC_BITS;
1.58 +
1.59 +/**
1.60 + * A MediaSegment is a chunk of media data sequential in time. Different
1.61 + * types of data have different subclasses of MediaSegment, all inheriting
1.62 + * from MediaSegmentBase.
1.63 + * All MediaSegment data is timed using TrackTicks. The actual tick rate
1.64 + * is defined on a per-track basis. For some track types, this can be
1.65 + * a fixed constant for all tracks of that type (e.g. 1MHz for video).
1.66 + *
1.67 + * Each media segment defines a concept of "null media data" (e.g. silence
1.68 + * for audio or "no video frame" for video), which can be efficiently
1.69 + * represented. This is used for padding.
1.70 + */
1.71 +class MediaSegment {
1.72 +public:
1.73 + virtual ~MediaSegment()
1.74 + {
1.75 + MOZ_COUNT_DTOR(MediaSegment);
1.76 + }
1.77 +
1.78 + enum Type {
1.79 + AUDIO,
1.80 + VIDEO,
1.81 + TYPE_COUNT
1.82 + };
1.83 +
1.84 + /**
1.85 + * Gets the total duration of the segment.
1.86 + */
1.87 + TrackTicks GetDuration() const { return mDuration; }
1.88 + Type GetType() const { return mType; }
1.89 +
1.90 + /**
1.91 + * Create a MediaSegment of the same type.
1.92 + */
1.93 + virtual MediaSegment* CreateEmptyClone() const = 0;
1.94 + /**
1.95 + * Moves contents of aSource to the end of this segment.
1.96 + */
1.97 + virtual void AppendFrom(MediaSegment* aSource) = 0;
1.98 + /**
1.99 + * Append a slice of aSource to this segment.
1.100 + */
1.101 + virtual void AppendSlice(const MediaSegment& aSource,
1.102 + TrackTicks aStart, TrackTicks aEnd) = 0;
1.103 + /**
1.104 + * Replace all contents up to aDuration with null data.
1.105 + */
1.106 + virtual void ForgetUpTo(TrackTicks aDuration) = 0;
1.107 + /**
1.108 + * Insert aDuration of null data at the start of the segment.
1.109 + */
1.110 + virtual void InsertNullDataAtStart(TrackTicks aDuration) = 0;
1.111 + /**
1.112 + * Insert aDuration of null data at the end of the segment.
1.113 + */
1.114 + virtual void AppendNullData(TrackTicks aDuration) = 0;
1.115 + /**
1.116 + * Replace contents with disabled data of the same duration
1.117 + */
1.118 + virtual void ReplaceWithDisabled() = 0;
1.119 + /**
1.120 + * Remove all contents, setting duration to 0.
1.121 + */
1.122 + virtual void Clear() = 0;
1.123 +
1.124 + virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
1.125 + {
1.126 + return 0;
1.127 + }
1.128 +
1.129 + virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
1.130 + {
1.131 + return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
1.132 + }
1.133 +
1.134 +protected:
1.135 + MediaSegment(Type aType) : mDuration(0), mType(aType)
1.136 + {
1.137 + MOZ_COUNT_CTOR(MediaSegment);
1.138 + }
1.139 +
1.140 + TrackTicks mDuration; // total of mDurations of all chunks
1.141 + Type mType;
1.142 +};
1.143 +
1.144 +/**
1.145 + * C is the implementation class subclassed from MediaSegmentBase.
1.146 + * C must contain a Chunk class.
1.147 + */
1.148 +template <class C, class Chunk> class MediaSegmentBase : public MediaSegment {
1.149 +public:
1.150 + virtual MediaSegment* CreateEmptyClone() const
1.151 + {
1.152 + return new C();
1.153 + }
1.154 + virtual void AppendFrom(MediaSegment* aSource)
1.155 + {
1.156 + NS_ASSERTION(aSource->GetType() == C::StaticType(), "Wrong type");
1.157 + AppendFromInternal(static_cast<C*>(aSource));
1.158 + }
1.159 + void AppendFrom(C* aSource)
1.160 + {
1.161 + AppendFromInternal(aSource);
1.162 + }
1.163 + virtual void AppendSlice(const MediaSegment& aSource,
1.164 + TrackTicks aStart, TrackTicks aEnd)
1.165 + {
1.166 + NS_ASSERTION(aSource.GetType() == C::StaticType(), "Wrong type");
1.167 + AppendSliceInternal(static_cast<const C&>(aSource), aStart, aEnd);
1.168 + }
1.169 + void AppendSlice(const C& aOther, TrackTicks aStart, TrackTicks aEnd)
1.170 + {
1.171 + AppendSliceInternal(aOther, aStart, aEnd);
1.172 + }
1.173 + /**
1.174 + * Replace the first aDuration ticks with null media data, because the data
1.175 + * will not be required again.
1.176 + */
1.177 + virtual void ForgetUpTo(TrackTicks aDuration)
1.178 + {
1.179 + if (mChunks.IsEmpty() || aDuration <= 0) {
1.180 + return;
1.181 + }
1.182 + if (mChunks[0].IsNull()) {
1.183 + TrackTicks extraToForget = std::min(aDuration, mDuration) - mChunks[0].GetDuration();
1.184 + if (extraToForget > 0) {
1.185 + RemoveLeading(extraToForget, 1);
1.186 + mChunks[0].mDuration += extraToForget;
1.187 + mDuration += extraToForget;
1.188 + }
1.189 + return;
1.190 + }
1.191 + RemoveLeading(aDuration, 0);
1.192 + mChunks.InsertElementAt(0)->SetNull(aDuration);
1.193 + mDuration += aDuration;
1.194 + }
1.195 + virtual void InsertNullDataAtStart(TrackTicks aDuration)
1.196 + {
1.197 + if (aDuration <= 0) {
1.198 + return;
1.199 + }
1.200 + if (!mChunks.IsEmpty() && mChunks[0].IsNull()) {
1.201 + mChunks[0].mDuration += aDuration;
1.202 + } else {
1.203 + mChunks.InsertElementAt(0)->SetNull(aDuration);
1.204 + }
1.205 +#ifdef MOZILLA_INTERNAL_API
1.206 + mChunks[0].mTimeStamp = mozilla::TimeStamp::Now();
1.207 +#endif
1.208 + mDuration += aDuration;
1.209 + }
1.210 + virtual void AppendNullData(TrackTicks aDuration)
1.211 + {
1.212 + if (aDuration <= 0) {
1.213 + return;
1.214 + }
1.215 + if (!mChunks.IsEmpty() && mChunks[mChunks.Length() - 1].IsNull()) {
1.216 + mChunks[mChunks.Length() - 1].mDuration += aDuration;
1.217 + } else {
1.218 + mChunks.AppendElement()->SetNull(aDuration);
1.219 + }
1.220 + mDuration += aDuration;
1.221 + }
1.222 + virtual void ReplaceWithDisabled()
1.223 + {
1.224 + if (GetType() != AUDIO) {
1.225 + MOZ_CRASH("Disabling unknown segment type");
1.226 + }
1.227 + TrackTicks duration = GetDuration();
1.228 + Clear();
1.229 + AppendNullData(duration);
1.230 + }
1.231 + virtual void Clear()
1.232 + {
1.233 + mDuration = 0;
1.234 + mChunks.Clear();
1.235 + }
1.236 +
1.237 + class ChunkIterator {
1.238 + public:
1.239 + ChunkIterator(MediaSegmentBase<C, Chunk>& aSegment)
1.240 + : mSegment(aSegment), mIndex(0) {}
1.241 + bool IsEnded() { return mIndex >= mSegment.mChunks.Length(); }
1.242 + void Next() { ++mIndex; }
1.243 + Chunk& operator*() { return mSegment.mChunks[mIndex]; }
1.244 + Chunk* operator->() { return &mSegment.mChunks[mIndex]; }
1.245 + private:
1.246 + MediaSegmentBase<C, Chunk>& mSegment;
1.247 + uint32_t mIndex;
1.248 + };
1.249 +
1.250 + void RemoveLeading(TrackTicks aDuration)
1.251 + {
1.252 + RemoveLeading(aDuration, 0);
1.253 + }
1.254 +
1.255 +#ifdef MOZILLA_INTERNAL_API
1.256 + void GetStartTime(TimeStamp &aTime) {
1.257 + aTime = mChunks[0].mTimeStamp;
1.258 + }
1.259 +#endif
1.260 +
1.261 + virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
1.262 + {
1.263 + size_t amount = mChunks.SizeOfExcludingThis(aMallocSizeOf);
1.264 + for (size_t i = 0; i < mChunks.Length(); i++) {
1.265 + amount += mChunks[i].SizeOfExcludingThisIfUnshared(aMallocSizeOf);
1.266 + }
1.267 + return amount;
1.268 + }
1.269 +
1.270 + virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
1.271 + {
1.272 + return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
1.273 + }
1.274 +
1.275 +protected:
1.276 + MediaSegmentBase(Type aType) : MediaSegment(aType) {}
1.277 +
1.278 + /**
1.279 + * Appends the contents of aSource to this segment, clearing aSource.
1.280 + */
1.281 + void AppendFromInternal(MediaSegmentBase<C, Chunk>* aSource)
1.282 + {
1.283 + MOZ_ASSERT(aSource->mDuration >= 0);
1.284 + mDuration += aSource->mDuration;
1.285 + aSource->mDuration = 0;
1.286 + if (!mChunks.IsEmpty() && !aSource->mChunks.IsEmpty() &&
1.287 + mChunks[mChunks.Length() - 1].CanCombineWithFollowing(aSource->mChunks[0])) {
1.288 + mChunks[mChunks.Length() - 1].mDuration += aSource->mChunks[0].mDuration;
1.289 + aSource->mChunks.RemoveElementAt(0);
1.290 + }
1.291 + mChunks.MoveElementsFrom(aSource->mChunks);
1.292 + }
1.293 +
1.294 + void AppendSliceInternal(const MediaSegmentBase<C, Chunk>& aSource,
1.295 + TrackTicks aStart, TrackTicks aEnd)
1.296 + {
1.297 + MOZ_ASSERT(aStart <= aEnd, "Endpoints inverted");
1.298 + NS_WARN_IF_FALSE(aStart >= 0 && aEnd <= aSource.mDuration, "Slice out of range");
1.299 + mDuration += aEnd - aStart;
1.300 + TrackTicks offset = 0;
1.301 + for (uint32_t i = 0; i < aSource.mChunks.Length() && offset < aEnd; ++i) {
1.302 + const Chunk& c = aSource.mChunks[i];
1.303 + TrackTicks start = std::max(aStart, offset);
1.304 + TrackTicks nextOffset = offset + c.GetDuration();
1.305 + TrackTicks end = std::min(aEnd, nextOffset);
1.306 + if (start < end) {
1.307 + mChunks.AppendElement(c)->SliceTo(start - offset, end - offset);
1.308 + }
1.309 + offset = nextOffset;
1.310 + }
1.311 + }
1.312 +
1.313 + Chunk* AppendChunk(TrackTicks aDuration)
1.314 + {
1.315 + MOZ_ASSERT(aDuration >= 0);
1.316 + Chunk* c = mChunks.AppendElement();
1.317 + c->mDuration = aDuration;
1.318 + mDuration += aDuration;
1.319 + return c;
1.320 + }
1.321 +
1.322 + Chunk* FindChunkContaining(TrackTicks aOffset, TrackTicks* aStart = nullptr)
1.323 + {
1.324 + if (aOffset < 0) {
1.325 + return nullptr;
1.326 + }
1.327 + TrackTicks offset = 0;
1.328 + for (uint32_t i = 0; i < mChunks.Length(); ++i) {
1.329 + Chunk& c = mChunks[i];
1.330 + TrackTicks nextOffset = offset + c.GetDuration();
1.331 + if (aOffset < nextOffset) {
1.332 + if (aStart) {
1.333 + *aStart = offset;
1.334 + }
1.335 + return &c;
1.336 + }
1.337 + offset = nextOffset;
1.338 + }
1.339 + return nullptr;
1.340 + }
1.341 +
1.342 + Chunk* GetLastChunk()
1.343 + {
1.344 + if (mChunks.IsEmpty()) {
1.345 + return nullptr;
1.346 + }
1.347 + return &mChunks[mChunks.Length() - 1];
1.348 + }
1.349 +
1.350 + void RemoveLeading(TrackTicks aDuration, uint32_t aStartIndex)
1.351 + {
1.352 + NS_ASSERTION(aDuration >= 0, "Can't remove negative duration");
1.353 + TrackTicks t = aDuration;
1.354 + uint32_t chunksToRemove = 0;
1.355 + for (uint32_t i = aStartIndex; i < mChunks.Length() && t > 0; ++i) {
1.356 + Chunk* c = &mChunks[i];
1.357 + if (c->GetDuration() > t) {
1.358 + c->SliceTo(t, c->GetDuration());
1.359 + t = 0;
1.360 + break;
1.361 + }
1.362 + t -= c->GetDuration();
1.363 + chunksToRemove = i + 1 - aStartIndex;
1.364 + }
1.365 + mChunks.RemoveElementsAt(aStartIndex, chunksToRemove);
1.366 + mDuration -= aDuration - t;
1.367 + }
1.368 +
1.369 + nsTArray<Chunk> mChunks;
1.370 +#ifdef MOZILLA_INTERNAL_API
1.371 + mozilla::TimeStamp mTimeStamp;
1.372 +#endif
1.373 +};
1.374 +
1.375 +}
1.376 +
1.377 +#endif /* MOZILLA_MEDIASEGMENT_H_ */
