安卓 如何实现内录，只录制手机播放的声音，而不录制话筒的声音

求大神指导，安卓 如何实现内录，只录制手机播放的声音，而不录制话筒的声音

请参考这篇文章：http://www.tuicool.com/articles/RVJFF3v。我试过，可行的，只不过需要系统签名，第三方app这种方式无法实现。
以下是android api：

  /**
         * Audio source for a submix of audio streams to be presented remotely.
         * <p>
         * An application can use this audio source to capture a mix of audio streams
         * that should be transmitted to a remote receiver such as a Wifi display.
         * While recording is active, these audio streams are redirected to the remote
         * submix instead of being played on the device speaker or headset.
         * </p><p>
         * Certain streams are excluded from the remote submix, including
         * {@link AudioManager#STREAM_RING}, {@link AudioManager#STREAM_ALARM},
         * and {@link AudioManager#STREAM_NOTIFICATION}.  These streams will continue
         * to be presented locally as usual.
         * </p><p>
         * Capturing the remote submix audio requires the
         * {@link android.Manifest.permission#CAPTURE_AUDIO_OUTPUT} permission.
         * This permission is reserved for use by system components and is not available to
         * third-party applications.
         * </p>
         */
        public static final int REMOTE_SUBMIX = 8;

我记得MediaRecorder类的这个属性setAudioSource方法中的MediaRecorder.AudioSource中一个属性值是控制录制的声音的

REMOTE_SUBMIX要系统应用或者root手机后才可以，果断放弃了，买了个内录插头，某宝搜索“3.5mm 耳机内录器 内录端子 内录头 游戏 直播声音内录无耳机监听”