diff -r 000000000000 -r 6474c204b198 content/media/fmp4/MP4Decoder.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/media/fmp4/MP4Decoder.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,108 @@
+/* -*- 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 "MP4Decoder.h"
+#include "MP4Reader.h"
+#include "MediaDecoderStateMachine.h"
+#include "mozilla/Preferences.h"
+
+#ifdef XP_WIN
+#include "mozilla/WindowsVersion.h"
+#endif
+#ifdef MOZ_FFMPEG
+#include "FFmpegDecoderModule.h"
+#endif
+
+namespace mozilla {
+
+MediaDecoderStateMachine* MP4Decoder::CreateStateMachine()
+{
+  return new MediaDecoderStateMachine(this, new MP4Reader(this));
+}
+
+bool
+MP4Decoder::GetSupportedCodecs(const nsACString& aType,
+                               char const *const ** aCodecList)
+{
+  if (!IsEnabled()) {
+    return false;
+  }
+
+  // AAC in M4A.
+  static char const *const aacAudioCodecs[] = {
+    "mp4a.40.2",    // AAC-LC
+    // TODO: AAC-HE ?
+    nullptr
+  };
+  if (aType.EqualsASCII("audio/mp4") ||
+      aType.EqualsASCII("audio/x-m4a")) {
+    if (aCodecList) {
+      *aCodecList = aacAudioCodecs;
+    }
+    return true;
+  }
+
+  // H.264 + AAC in MP4.
+  static char const *const h264Codecs[] = {
+    "avc1.42E01E",  // H.264 Constrained Baseline Profile Level 3.0
+    "avc1.42001E",  // H.264 Baseline Profile Level 3.0
+    "avc1.58A01E",  // H.264 Extended Profile Level 3.0
+    "avc1.4D401E",  // H.264 Main Profile Level 3.0
+    "avc1.64001E",  // H.264 High Profile Level 3.0
+    "avc1.64001F",  // H.264 High Profile Level 3.1
+    "mp4a.40.2",    // AAC-LC
+    // TODO: There must be more profiles here?
+    nullptr
+  };
+  if (aType.EqualsASCII("video/mp4")) {
+    if (aCodecList) {
+      *aCodecList = h264Codecs;
+    }
+    return true;
+  }
+
+  return false;
+}
+
+static bool
+IsFFmpegAvailable()
+{
+#ifndef MOZ_FFMPEG
+  return false;
+#else
+  if (!Preferences::GetBool("media.fragmented-mp4.ffmpeg.enabled", false)) {
+    return false;
+  }
+
+  // If we can link to FFmpeg, then we can almost certainly play H264 and AAC
+  // with it.
+  return FFmpegDecoderModule::Link();
+#endif
+}
+
+static bool
+HavePlatformMPEGDecoders()
+{
+  return Preferences::GetBool("media.fragmented-mp4.use-blank-decoder") ||
+#ifdef XP_WIN
+         // We have H.264/AAC platform decoders on Windows Vista and up.
+         IsVistaOrLater() ||
+#endif
+         IsFFmpegAvailable() ||
+         // TODO: Other platforms...
+         false;
+}
+
+/* static */
+bool
+MP4Decoder::IsEnabled()
+{
+  return HavePlatformMPEGDecoders() &&
+         Preferences::GetBool("media.fragmented-mp4.enabled");
+}
+
+} // namespace mozilla
+