使用MediaRecorder时，视频在Android中旋转了90度

Question

我在android中使用MediaRecorder录制.mp4。我使用android4ffmpeg lib减慢速度，然后将视频（.mp4）旋转90度。我该如何解决？

如果使用.mp4（在Android中通过手机摄像头录制），请不要旋转！但是使用MediaRecorder它总是旋转90度。

命令是

String[] complexCommand = { "ffmpeg", "-y", "-i", "", "-strict",
        "experimental", "-filter_complex",
        "[0:v]setpts=4.0*PTS[v];[0:a]atempo=2.0[a]", "-map", "[v]",
        "-map", "[a]", "-b", "2097k", "-r", "60", "-vcodec", "mpeg4",
        "" };

mediarecorder

            recorder.setCamera(mCamera);
            recorder.setPreviewDisplay(sufaceHolder.getSurface());
            recorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
            recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);

            recorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));
            recorder.setOutputFile(inFileName);
//          recorder.setOrientationHint(90);
            recorder.prepare();
            recorder.start();