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 /* -*- 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/. */

 #include "WMF.h"

 #include "WMFDecoder.h"

 #include "WMFReader.h"

 #include "WMFUtils.h"

 #include "MediaDecoderStateMachine.h"

 #include "mozilla/Preferences.h"

 #include "mozilla/WindowsVersion.h"

 #include "nsCharSeparatedTokenizer.h"

 #ifdef MOZ_DIRECTSHOW

 #include "DirectShowDecoder.h"

 #endif

 namespace mozilla {

 MediaDecoderStateMachine* WMFDecoder::CreateStateMachine()

 {

   return new MediaDecoderStateMachine(this, new WMFReader(this));

 }

 /* static */

 bool

 WMFDecoder::IsMP3Supported()

 {

   MOZ_ASSERT(NS_IsMainThread(), "Must be on main thread.");

   if (!MediaDecoder::IsWMFEnabled()) {

     return false;

   }

   // MP3 works fine in WMF on Windows Vista and Windows 8.

   if (!IsWin7OrLater()) {

     return true;

   }

   // MP3 support is disabled if we're on Windows 7 and no service packs are

   // installed, since it's crashy. Win7 with service packs is not so crashy,

   // so we enable it there. Note we prefer DirectShow for MP3 playback, but

   // we still support MP3 in MP4 via WMF, or MP3 in WMF if DirectShow is

   // disabled.

   return IsWin7SP1OrLater();

 }

 static bool

 IsSupportedH264Codec(const nsAString& aCodec)

 {

   // According to the WMF documentation:

   // http://msdn.microsoft.com/en-us/library/windows/desktop/dd797815%28v=vs.85%29.aspx

   // "The Media Foundation H.264 video decoder is a Media Foundation Transform

   // that supports decoding of Baseline, Main, and High profiles, up to level

   // 5.1.". We also report that we can play Extended profile, as there are

   // bitstreams that are Extended compliant that are also Baseline compliant.

   // H.264 codecs parameters have a type defined as avc1.PPCCLL, where

   // PP = profile_idc, CC = constraint_set flags, LL = level_idc.

   // We ignore the constraint_set flags, as it's not clear from the WMF

   // documentation what constraints the WMF H.264 decoder supports.

   // See http://blog.pearce.org.nz/2013/11/what-does-h264avc1-codecs-parameters.html

   // for more details.

   if (aCodec.Length() != strlen("avc1.PPCCLL")) {

     return false;

   }

   // Verify the codec starts with "avc1.".

   const nsAString& sample = Substring(aCodec, 0, 5);

   if (!sample.EqualsASCII("avc1.")) {

     return false;

   }

   // Extract the profile_idc and level_idc. Note: the constraint_set flags

   // are ignored, it's not clear from the WMF documentation if they make a

   // difference.

   nsresult rv = NS_OK;

   const int32_t profile = PromiseFlatString(Substring(aCodec, 5, 2)).ToInteger(&rv, 16);

   NS_ENSURE_SUCCESS(rv, false);

   const int32_t level = PromiseFlatString(Substring(aCodec, 9, 2)).ToInteger(&rv, 16);

   NS_ENSURE_SUCCESS(rv, false);

   return level >= eAVEncH264VLevel1 &&

          level <= eAVEncH264VLevel5_1 &&

          (profile == eAVEncH264VProfile_Base ||

           profile == eAVEncH264VProfile_Main ||

           profile == eAVEncH264VProfile_Extended ||

           profile == eAVEncH264VProfile_High);

 }

 bool

 WMFDecoder::CanPlayType(const nsACString& aType,

                         const nsAString& aCodecs)

 {

   if (!MediaDecoder::IsWMFEnabled() ||

       NS_FAILED(LoadDLLs())) {

     return false;

   }

   // Assume that if LoadDLLs() didn't fail, we can playback the types that

   // we know should be supported by Windows Media Foundation.

   if ((aType.EqualsASCII("audio/mpeg") || aType.EqualsASCII("audio/mp3")) &&

       IsMP3Supported()) {

     // Note: We block MP3 playback on Window 7 SP0 since it seems to crash

     // in some circumstances.

     return !aCodecs.Length() || aCodecs.EqualsASCII("mp3");

   }

   // AAC-LC or MP3 in M4A.

   if (aType.EqualsASCII("audio/mp4") || aType.EqualsASCII("audio/x-m4a")) {

     return !aCodecs.Length() ||

            aCodecs.EqualsASCII("mp4a.40.2") ||

            aCodecs.EqualsASCII("mp3");

   }

   if (!aType.EqualsASCII("video/mp4")) {

     return false;

   }

   // H.264 + AAC in MP4. Verify that all the codecs specifed are ones that

   // we expect that we can play.

   nsCharSeparatedTokenizer tokenizer(aCodecs, ',');

   bool expectMoreTokens = false;

   while (tokenizer.hasMoreTokens()) {

     const nsSubstring& token = tokenizer.nextToken();

     expectMoreTokens = tokenizer.separatorAfterCurrentToken();

     if (token.EqualsASCII("mp4a.40.2") || // AAC-LC

         token.EqualsASCII("mp3") ||

         IsSupportedH264Codec(token)) {

       continue;

     }

     return false;

   }

   if (expectMoreTokens) {

     // Last codec name was empty

     return false;

   }

   return true;

 }

 nsresult

 WMFDecoder::LoadDLLs()

 {

   return SUCCEEDED(wmf::LoadDLLs()) ? NS_OK : NS_ERROR_FAILURE;

 }

 void

 WMFDecoder::UnloadDLLs()

 {

   wmf::UnloadDLLs();

 }

 /* static */

 bool

 WMFDecoder::IsEnabled()

 {

   // We only use WMF on Windows Vista and up

   return IsVistaOrLater() &&

          Preferences::GetBool("media.windows-media-foundation.enabled");

 }

 } // namespace mozilla