gecko/dom/media/wmf/WMFDecoder.h

/* -*- 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/. */
#if !defined(WMFDecoder_h_)
#define WMFDecoder_h_

#include "MediaDecoder.h"

namespace mozilla {

// Decoder that uses Windows Media Foundation to playback H.264/AAC in MP4
// and M4A files, and MP3 files if the DirectShow backend is disabled.
// Playback is strictly limited to only those codecs.
class WMFDecoder : public MediaDecoder
{
public:

  virtual MediaDecoder* Clone() {
    if (!IsWMFEnabled()) {
      return nullptr;
    }
    return new WMFDecoder();
  }

  virtual MediaDecoderStateMachine* CreateStateMachine();

  // Loads the DLLs required by Windows Media Foundation. If this returns
  // failure, you can assume that WMF is not available on the user's system.
  static nsresult LoadDLLs();
  static void UnloadDLLs();

  // Returns true if the WMF backend is preffed on, and we're running on a
  // version of Windows which is likely to support WMF.
  static bool IsEnabled();

  // Returns true if MP3 decoding is enabled on this system. We block
  // MP3 playback on Windows 7 SP0, since it's crashy on that platform.
  static bool IsMP3Supported();

  // Returns the HTMLMediaElement.canPlayType() result for the mime type
  // and codecs parameter. aCodecs can be empty.
  static bool CanPlayType(const nsACString& aType,
                          const nsAString& aCodecs);

};

} // namespace mozilla

#endif