I try to use the MediaRecorder class to record a video but I get an exception : failed to get Camera parameters. Prepare failed.

Here's my code :

        camera = Camera.open();
        recorder = new MediaRecorder();
        recorder.setCamera(camera);
        recorder.setVideoSource(VideoSource.CAMERA);
        recorder.setPreviewDisplay(m_holder.getSurface());
        recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        recorder.setVideoEncoder(MediaRecorder.VideoEncoder.DEFAULT);
        recorder.setMaxDuration(10000);
        recorder.setOutputFile(file.getPath());
        recorder.prepare();

Any idea ?