dom/media/VideoUtils.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef VideoUtils_h
   8 #define VideoUtils_h
   9
  10 #include "AudioSampleFormat.h"
  11 #include "MediaInfo.h"
  12 #include "TimeUnits.h"
  13 #include "VideoLimits.h"
  14 #include "mozilla/AbstractThread.h"
  15 #include "mozilla/Attributes.h"
  16 #include "mozilla/CheckedInt.h"
  17 #include "mozilla/MozPromise.h"
  18 #include "mozilla/ReentrantMonitor.h"
  19 #include "mozilla/RefPtr.h"
  20 #include "mozilla/SharedThreadPool.h"
  21 #include "mozilla/TaskQueue.h"
  22 #include "mozilla/UniquePtr.h"
  23 #include "mozilla/gfx/Point.h"  // for gfx::IntSize
  24 #include "mozilla/gfx/Types.h"
  25 #include "nsCOMPtr.h"
  26 #include "nsINamed.h"
  27 #include "nsIThread.h"
  28 #include "nsITimer.h"
  29 #include "nsThreadUtils.h"
  30 #include "prtime.h"
  31
  32 using mozilla::CheckedInt32;
  33 using mozilla::CheckedInt64;
  34 using mozilla::CheckedUint32;
  35 using mozilla::CheckedUint64;
  36
  37 // This file contains stuff we'd rather put elsewhere, but which is
  38 // dependent on other changes which we don't want to wait for. We plan to
  39 // remove this file in the near future.
  40
  41 // This belongs in xpcom/monitor/Monitor.h, once we've made
  42 // mozilla::Monitor non-reentrant.
  43 namespace mozilla {
  44
  45 class MediaContainerType;
  46
  47 // EME Key System String.
  48 #define EME_KEY_SYSTEM_CLEARKEY "org.w3.clearkey"
  49 #define EME_KEY_SYSTEM_WIDEVINE "com.widevine.alpha"
  50
  51 /**
  52  * ReentrantMonitorConditionallyEnter
  53  *
  54  * Enters the supplied monitor only if the conditional value |aEnter| is true.
  55  * E.g. Used to allow unmonitored read access on the decode thread,
  56  * and monitored access on all other threads.
  57  */
  58 class MOZ_STACK_CLASS ReentrantMonitorConditionallyEnter {
  59  public:
  60   ReentrantMonitorConditionallyEnter(bool aEnter,
  61                                      ReentrantMonitor& aReentrantMonitor)
  62       : mReentrantMonitor(nullptr) {
  63     MOZ_COUNT_CTOR(ReentrantMonitorConditionallyEnter);
  64     if (aEnter) {
  65       mReentrantMonitor = &aReentrantMonitor;
  66       NS_ASSERTION(mReentrantMonitor, "null monitor");
  67       mReentrantMonitor->Enter();
  68     }
  69   }
  70   ~ReentrantMonitorConditionallyEnter(void) {
  71     if (mReentrantMonitor) {
  72       mReentrantMonitor->Exit();
  73     }
  74     MOZ_COUNT_DTOR(ReentrantMonitorConditionallyEnter);
  75   }
  76
  77  private:
  78   // Restrict to constructor and destructor defined above.
  79   ReentrantMonitorConditionallyEnter();
  80   ReentrantMonitorConditionallyEnter(const ReentrantMonitorConditionallyEnter&);
  81   ReentrantMonitorConditionallyEnter& operator=(
  82       const ReentrantMonitorConditionallyEnter&);
  83   static void* operator new(size_t) noexcept(true);
  84   static void operator delete(void*);
  85
  86   ReentrantMonitor* mReentrantMonitor;
  87 };
  88
  89 // Shuts down a thread asynchronously.
  90 class ShutdownThreadEvent : public Runnable {
  91  public:
  92   explicit ShutdownThreadEvent(nsIThread* aThread)
  93       : Runnable("ShutdownThreadEvent"), mThread(aThread) {}
  94   ~ShutdownThreadEvent() = default;
  95   NS_IMETHOD Run() override {
  96     mThread->Shutdown();
  97     mThread = nullptr;
  98     return NS_OK;
  99   }
 100
 101  private:
 102   nsCOMPtr<nsIThread> mThread;
 103 };
 104
 105 class MediaResource;
 106
 107 // Estimates the buffered ranges of a MediaResource using a simple
 108 // (byteOffset/length)*duration method. Probably inaccurate, but won't
 109 // do file I/O, and can be used when we don't have detailed knowledge
 110 // of the byte->time mapping of a resource. aDurationUsecs is the duration
 111 // of the media in microseconds. Estimated buffered ranges are stored in
 112 // aOutBuffered. Ranges are 0-normalized, i.e. in the range of (0,duration].
 113 media::TimeIntervals GetEstimatedBufferedTimeRanges(
 114     mozilla::MediaResource* aStream, int64_t aDurationUsecs);
 115
 116 // Converts from number of audio frames (aFrames) to microseconds, given
 117 // the specified audio rate (aRate).
 118 CheckedInt64 FramesToUsecs(int64_t aFrames, uint32_t aRate);
 119 // Converts from number of audio frames (aFrames) TimeUnit, given
 120 // the specified audio rate (aRate).
 121 media::TimeUnit FramesToTimeUnit(int64_t aFrames, uint32_t aRate);
 122 // Perform aValue * aMul / aDiv, reducing the possibility of overflow due to
 123 // aValue * aMul overflowing.
 124 CheckedInt64 SaferMultDiv(int64_t aValue, uint64_t aMul, uint64_t aDiv);
 125
 126 // Converts from microseconds (aUsecs) to number of audio frames, given the
 127 // specified audio rate (aRate). Stores the result in aOutFrames. Returns
 128 // true if the operation succeeded, or false if there was an integer
 129 // overflow while calulating the conversion.
 130 CheckedInt64 UsecsToFrames(int64_t aUsecs, uint32_t aRate);
 131
 132 // Format TimeUnit as number of frames at given rate.
 133 CheckedInt64 TimeUnitToFrames(const media::TimeUnit& aTime, uint32_t aRate);
 134
 135 // Converts milliseconds to seconds.
 136 #define MS_TO_SECONDS(ms) ((double)(ms) / (PR_MSEC_PER_SEC))
 137
 138 // Converts seconds to milliseconds.
 139 #define SECONDS_TO_MS(s) ((int)((s) * (PR_MSEC_PER_SEC)))
 140
 141 // Converts from seconds to microseconds. Returns failure if the resulting
 142 // integer is too big to fit in an int64_t.
 143 nsresult SecondsToUsecs(double aSeconds, int64_t& aOutUsecs);
 144
 145 // Scales the display rect aDisplay by aspect ratio aAspectRatio.
 146 // Note that aDisplay must be validated by IsValidVideoRegion()
 147 // before being used!
 148 void ScaleDisplayByAspectRatio(gfx::IntSize& aDisplay, float aAspectRatio);
 149
 150 // Downmix Stereo audio samples to Mono.
 151 // Input are the buffer contains stereo data and the number of frames.
 152 void DownmixStereoToMono(mozilla::AudioDataValue* aBuffer, uint32_t aFrames);
 153
 154 // Decide the number of playback channels according to the
 155 // given AudioInfo and the prefs that are being set.
 156 uint32_t DecideAudioPlaybackChannels(const AudioInfo& info);
 157
 158 // Decide the sample-rate to use for audio output according to the
 159 // given AudioInfo and the prefs that are being set.
 160 uint32_t DecideAudioPlaybackSampleRate(const AudioInfo& info);
 161
 162 bool IsDefaultPlaybackDeviceMono();
 163
 164 bool IsVideoContentType(const nsCString& aContentType);
 165
 166 // Returns true if it's safe to use aPicture as the picture to be
 167 // extracted inside a frame of size aFrame, and scaled up to and displayed
 168 // at a size of aDisplay. You should validate the frame, picture, and
 169 // display regions before using them to display video frames.
 170 bool IsValidVideoRegion(const gfx::IntSize& aFrame,
 171                         const gfx::IntRect& aPicture,
 172                         const gfx::IntSize& aDisplay);
 173
 174 // Template to automatically set a variable to a value on scope exit.
 175 // Useful for unsetting flags, etc.
 176 template <typename T>
 177 class AutoSetOnScopeExit {
 178  public:
 179   AutoSetOnScopeExit(T& aVar, T aValue) : mVar(aVar), mValue(aValue) {}
 180   ~AutoSetOnScopeExit() { mVar = mValue; }
 181
 182  private:
 183   T& mVar;
 184   const T mValue;
 185 };
 186
 187 enum class MediaThreadType {
 188   SUPERVISOR,  // MediaFormatReader, RemoteDecoderManager, MediaDecodeTask and
 189                // others
 190   PLATFORM_DECODER,  // MediaDataDecoder
 191   PLATFORM_ENCODER,  // MediaDataEncoder
 192   WEBRTC_DECODER,
 193   MDSM,  // MediaDecoderStateMachine
 194 };
 195 // Returns the thread pool that is shared amongst all decoder state machines
 196 // for decoding streams.
 197 already_AddRefed<SharedThreadPool> GetMediaThreadPool(MediaThreadType aType);
 198
 199 enum H264_PROFILE {
 200   H264_PROFILE_UNKNOWN = 0,
 201   H264_PROFILE_BASE = 0x42,
 202   H264_PROFILE_MAIN = 0x4D,
 203   H264_PROFILE_EXTENDED = 0x58,
 204   H264_PROFILE_HIGH = 0x64,
 205 };
 206
 207 enum H264_LEVEL {
 208   H264_LEVEL_1 = 10,
 209   H264_LEVEL_1_b = 11,
 210   H264_LEVEL_1_1 = 11,
 211   H264_LEVEL_1_2 = 12,
 212   H264_LEVEL_1_3 = 13,
 213   H264_LEVEL_2 = 20,
 214   H264_LEVEL_2_1 = 21,
 215   H264_LEVEL_2_2 = 22,
 216   H264_LEVEL_3 = 30,
 217   H264_LEVEL_3_1 = 31,
 218   H264_LEVEL_3_2 = 32,
 219   H264_LEVEL_4 = 40,
 220   H264_LEVEL_4_1 = 41,
 221   H264_LEVEL_4_2 = 42,
 222   H264_LEVEL_5 = 50,
 223   H264_LEVEL_5_1 = 51,
 224   H264_LEVEL_5_2 = 52
 225 };
 226
 227 // Extracts the H.264/AVC profile and level from an H.264 codecs string.
 228 // H.264 codecs parameters have a type defined as avc1.PPCCLL, where
 229 // PP = profile_idc, CC = constraint_set flags, LL = level_idc.
 230 // See
 231 // http://blog.pearce.org.nz/2013/11/what-does-h264avc1-codecs-parameters.html
 232 // for more details.
 233 // Returns false on failure.
 234 bool ExtractH264CodecDetails(const nsAString& aCodecs, uint8_t& aProfile,
 235                              uint8_t& aConstraint, uint8_t& aLevel);
 236
 237 struct VideoColorSpace {
 238   // TODO: Define the value type as strong type enum
 239   // to better know the exact meaning corresponding to ISO/IEC 23001-8:2016.
 240   // Default value is listed
 241   // https://www.webmproject.org/vp9/mp4/#optional-fields
 242   uint8_t mPrimaryId = 1;   // Table 2
 243   uint8_t mTransferId = 1;  // Table 3
 244   uint8_t mMatrixId = 1;    // Table 4
 245   uint8_t mRangeId = 0;
 246 };
 247
 248 // Extracts the VPX codecs parameter string.
 249 // See https://www.webmproject.org/vp9/mp4/#codecs-parameter-string
 250 // for more details.
 251 // Returns false on failure.
 252 bool ExtractVPXCodecDetails(const nsAString& aCodec, uint8_t& aProfile,
 253                             uint8_t& aLevel, uint8_t& aBitDepth);
 254 bool ExtractVPXCodecDetails(const nsAString& aCodec, uint8_t& aProfile,
 255                             uint8_t& aLevel, uint8_t& aBitDepth,
 256                             uint8_t& aChromaSubsampling,
 257                             VideoColorSpace& aColorSpace);
 258
 259 // Use a cryptographic quality PRNG to generate raw random bytes
 260 // and convert that to a base64 string.
 261 nsresult GenerateRandomName(nsCString& aOutSalt, uint32_t aLength);
 262
 263 // This version returns a string suitable for use as a file or URL
 264 // path. This is based on code from nsExternalAppHandler::SetUpTempFile.
 265 nsresult GenerateRandomPathName(nsCString& aOutSalt, uint32_t aLength);
 266
 267 already_AddRefed<TaskQueue> CreateMediaDecodeTaskQueue(const char* aName);
 268
 269 // Iteratively invokes aWork until aCondition returns true, or aWork returns
 270 // false. Use this rather than a while loop to avoid bogarting the task queue.
 271 template <class Work, class Condition>
 272 RefPtr<GenericPromise> InvokeUntil(Work aWork, Condition aCondition) {
 273   RefPtr<GenericPromise::Private> p = new GenericPromise::Private(__func__);
 274
 275   if (aCondition()) {
 276     p->Resolve(true, __func__);
 277   }
 278
 279   struct Helper {
 280     static void Iteration(const RefPtr<GenericPromise::Private>& aPromise,
 281                           Work aLocalWork, Condition aLocalCondition) {
 282       if (!aLocalWork()) {
 283         aPromise->Reject(NS_ERROR_FAILURE, __func__);
 284       } else if (aLocalCondition()) {
 285         aPromise->Resolve(true, __func__);
 286       } else {
 287         nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction(
 288             "InvokeUntil::Helper::Iteration",
 289             [aPromise, aLocalWork, aLocalCondition]() {
 290               Iteration(aPromise, aLocalWork, aLocalCondition);
 291             });
 292         AbstractThread::GetCurrent()->Dispatch(r.forget());
 293       }
 294     }
 295   };
 296
 297   Helper::Iteration(p, aWork, aCondition);
 298   return p;
 299 }
 300
 301 // Simple timer to run a runnable after a timeout.
 302 class SimpleTimer : public nsITimerCallback, public nsINamed {
 303  public:
 304   NS_DECL_ISUPPORTS
 305   NS_DECL_NSINAMED
 306
 307   // Create a new timer to run aTask after aTimeoutMs milliseconds
 308   // on thread aTarget. If aTarget is null, task is run on the main thread.
 309   static already_AddRefed<SimpleTimer> Create(
 310       nsIRunnable* aTask, uint32_t aTimeoutMs,
 311       nsIEventTarget* aTarget = nullptr);
 312   void Cancel();
 313
 314   NS_IMETHOD Notify(nsITimer* timer) override;
 315
 316  private:
 317   virtual ~SimpleTimer() = default;
 318   nsresult Init(nsIRunnable* aTask, uint32_t aTimeoutMs,
 319                 nsIEventTarget* aTarget);
 320
 321   RefPtr<nsIRunnable> mTask;
 322   nsCOMPtr<nsITimer> mTimer;
 323 };
 324
 325 void LogToBrowserConsole(const nsAString& aMsg);
 326
 327 bool ParseMIMETypeString(const nsAString& aMIMEType,
 328                          nsString& aOutContainerType,
 329                          nsTArray<nsString>& aOutCodecs);
 330
 331 bool ParseCodecsString(const nsAString& aCodecs,
 332                        nsTArray<nsString>& aOutCodecs);
 333
 334 bool IsH264CodecString(const nsAString& aCodec);
 335
 336 bool IsAACCodecString(const nsAString& aCodec);
 337
 338 bool IsVP8CodecString(const nsAString& aCodec);
 339
 340 bool IsVP9CodecString(const nsAString& aCodec);
 341
 342 bool IsAV1CodecString(const nsAString& aCodec);
 343
 344 // Try and create a TrackInfo with a given codec MIME type.
 345 UniquePtr<TrackInfo> CreateTrackInfoWithMIMEType(
 346     const nsACString& aCodecMIMEType);
 347
 348 // Try and create a TrackInfo with a given codec MIME type, and optional extra
 349 // parameters from a container type (its MIME type and codecs are ignored).
 350 UniquePtr<TrackInfo> CreateTrackInfoWithMIMETypeAndContainerTypeExtraParameters(
 351     const nsACString& aCodecMIMEType, const MediaContainerType& aContainerType);
 352
 353 namespace detail {
 354
 355 // aString should start with aMajor + '/'.
 356 constexpr bool StartsWithMIMETypeMajor(const char* aString, const char* aMajor,
 357                                        size_t aMajorRemaining) {
 358   return (aMajorRemaining == 0 && *aString == '/') ||
 359          (*aString == *aMajor &&
 360           StartsWithMIMETypeMajor(aString + 1, aMajor + 1,
 361                                   aMajorRemaining - 1));
 362 }
 363
 364 // aString should only contain [a-z0-9\-\.] and a final '\0'.
 365 constexpr bool EndsWithMIMESubtype(const char* aString, size_t aRemaining) {
 366   return aRemaining == 0 || (((*aString >= 'a' && *aString <= 'z') ||
 367                               (*aString >= '0' && *aString <= '9') ||
 368                               *aString == '-' || *aString == '.') &&
 369                              EndsWithMIMESubtype(aString + 1, aRemaining - 1));
 370 }
 371
 372 // Simple MIME-type literal string checker with a given (major) type.
 373 // Only accepts "{aMajor}/[a-z0-9\-\.]+".
 374 template <size_t MajorLengthPlus1>
 375 constexpr bool IsMIMETypeWithMajor(const char* aString, size_t aLength,
 376                                    const char (&aMajor)[MajorLengthPlus1]) {
 377   return aLength > MajorLengthPlus1 &&  // Major + '/' + at least 1 char
 378          StartsWithMIMETypeMajor(aString, aMajor, MajorLengthPlus1 - 1) &&
 379          EndsWithMIMESubtype(aString + MajorLengthPlus1,
 380                              aLength - MajorLengthPlus1);
 381 }
 382
 383 }  // namespace detail
 384
 385 // Simple MIME-type string checker.
 386 // Only accepts lowercase "{application,audio,video}/[a-z0-9\-\.]+".
 387 // Add more if necessary.
 388 constexpr bool IsMediaMIMEType(const char* aString, size_t aLength) {
 389   return detail::IsMIMETypeWithMajor(aString, aLength, "application") ||
 390          detail::IsMIMETypeWithMajor(aString, aLength, "audio") ||
 391          detail::IsMIMETypeWithMajor(aString, aLength, "video");
 392 }
 393
 394 // Simple MIME-type string literal checker.
 395 // Only accepts lowercase "{application,audio,video}/[a-z0-9\-\.]+".
 396 // Add more if necessary.
 397 template <size_t LengthPlus1>
 398 constexpr bool IsMediaMIMEType(const char (&aString)[LengthPlus1]) {
 399   return IsMediaMIMEType(aString, LengthPlus1 - 1);
 400 }
 401
 402 // Simple MIME-type string checker.
 403 // Only accepts lowercase "{application,audio,video}/[a-z0-9\-\.]+".
 404 // Add more if necessary.
 405 inline bool IsMediaMIMEType(const nsACString& aString) {
 406   return IsMediaMIMEType(aString.Data(), aString.Length());
 407 }
 408
 409 enum class StringListRangeEmptyItems {
 410   // Skip all empty items (empty string will process nothing)
 411   // E.g.: "a,,b" -> ["a", "b"], "" -> nothing
 412   Skip,
 413   // Process all, except if string is empty
 414   // E.g.: "a,,b" -> ["a", "", "b"], "" -> nothing
 415   ProcessEmptyItems,
 416   // Process all, including 1 empty item in an empty string
 417   // E.g.: "a,,b" -> ["a", "", "b"], "" -> [""]
 418   ProcessAll
 419 };
 420
 421 template <typename String,
 422           StringListRangeEmptyItems empties = StringListRangeEmptyItems::Skip>
 423 class StringListRange {
 424   typedef typename String::char_type CharType;
 425   typedef const CharType* Pointer;
 426
 427  public:
 428   // Iterator into range, trims items and optionally skips empty items.
 429   class Iterator {
 430    public:
 431     bool operator!=(const Iterator& a) const {
 432       return mStart != a.mStart || mEnd != a.mEnd;
 433     }
 434     Iterator& operator++() {
 435       SearchItemAt(mComma + 1);
 436       return *this;
 437     }
 438     // DereferencedType should be 'const nsDependent[C]String' pointing into
 439     // mList (which is 'const ns[C]String&').
 440     typedef decltype(Substring(Pointer(), Pointer())) DereferencedType;
 441     DereferencedType operator*() { return Substring(mStart, mEnd); }
 442
 443    private:
 444     friend class StringListRange;
 445     Iterator(const CharType* aRangeStart, uint32_t aLength)
 446         : mRangeEnd(aRangeStart + aLength),
 447           mStart(nullptr),
 448           mEnd(nullptr),
 449           mComma(nullptr) {
 450       SearchItemAt(aRangeStart);
 451     }
 452     void SearchItemAt(Pointer start) {
 453       // First, skip leading whitespace.
 454       for (Pointer p = start;; ++p) {
 455         if (p >= mRangeEnd) {
 456           if (p > mRangeEnd +
 457                       (empties != StringListRangeEmptyItems::Skip ? 1 : 0)) {
 458             p = mRangeEnd +
 459                 (empties != StringListRangeEmptyItems::Skip ? 1 : 0);
 460           }
 461           mStart = mEnd = mComma = p;
 462           return;
 463         }
 464         auto c = *p;
 465         if (c == CharType(',')) {
 466           // Comma -> Empty item -> Skip or process?
 467           if (empties != StringListRangeEmptyItems::Skip) {
 468             mStart = mEnd = mComma = p;
 469             return;
 470           }
 471         } else if (c != CharType(' ')) {
 472           mStart = p;
 473           break;
 474         }
 475       }
 476       // Find comma, recording start of trailing space.
 477       Pointer trailingWhitespace = nullptr;
 478       for (Pointer p = mStart + 1;; ++p) {
 479         if (p >= mRangeEnd) {
 480           mEnd = trailingWhitespace ? trailingWhitespace : p;
 481           mComma = p;
 482           return;
 483         }
 484         auto c = *p;
 485         if (c == CharType(',')) {
 486           mEnd = trailingWhitespace ? trailingWhitespace : p;
 487           mComma = p;
 488           return;
 489         }
 490         if (c == CharType(' ')) {
 491           // Found a whitespace -> Record as trailing if not first one.
 492           if (!trailingWhitespace) {
 493             trailingWhitespace = p;
 494           }
 495         } else {
 496           // Found a non-whitespace -> Reset trailing whitespace if needed.
 497           if (trailingWhitespace) {
 498             trailingWhitespace = nullptr;
 499           }
 500         }
 501       }
 502     }
 503     const Pointer mRangeEnd;
 504     Pointer mStart;
 505     Pointer mEnd;
 506     Pointer mComma;
 507   };
 508
 509   explicit StringListRange(const String& aList) : mList(aList) {}
 510   Iterator begin() const {
 511     return Iterator(
 512         mList.Data() +
 513             ((empties == StringListRangeEmptyItems::ProcessEmptyItems &&
 514               mList.Length() == 0)
 515                  ? 1
 516                  : 0),
 517         mList.Length());
 518   }
 519   Iterator end() const {
 520     return Iterator(mList.Data() + mList.Length() +
 521                         (empties != StringListRangeEmptyItems::Skip ? 1 : 0),
 522                     0);
 523   }
 524
 525  private:
 526   const String& mList;
 527 };
 528
 529 template <StringListRangeEmptyItems empties = StringListRangeEmptyItems::Skip,
 530           typename String>
 531 StringListRange<String, empties> MakeStringListRange(const String& aList) {
 532   return StringListRange<String, empties>(aList);
 533 }
 534
 535 template <StringListRangeEmptyItems empties = StringListRangeEmptyItems::Skip,
 536           typename ListString, typename ItemString>
 537 static bool StringListContains(const ListString& aList,
 538                                const ItemString& aItem) {
 539   for (const auto& listItem : MakeStringListRange<empties>(aList)) {
 540     if (listItem.Equals(aItem)) {
 541       return true;
 542     }
 543   }
 544   return false;
 545 }
 546
 547 inline void AppendStringIfNotEmpty(nsACString& aDest, nsACString&& aSrc) {
 548   if (!aSrc.IsEmpty()) {
 549     aDest.Append("\n"_ns);
 550     aDest.Append(aSrc);
 551   }
 552 }
 553
 554 // Returns true if we're running on a cellular connection; 2G, 3G, etc.
 555 // Main thread only.
 556 bool OnCellularConnection();
 557
 558 inline gfx::YUVColorSpace DefaultColorSpace(const gfx::IntSize& aSize) {
 559   return aSize.height < 720 ? gfx::YUVColorSpace::BT601
 560                             : gfx::YUVColorSpace::BT709;
 561 }
 562
 563 }  // end namespace mozilla
 564
 565 #endif