The Tor Browser: comparison content/media/wmf/WMFDecoder.cpp

--1:000000000000
+:11ee682ab098
+/* -*- 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

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comparison: content/media/wmf/WMFDecoder.cpp

content/media/wmf/WMFDecoder.cpp