camcorder effect support

VideoCamera.java

    private void loadCameraPreferences() {
        CameraSettings settings = new CameraSettings(this,mParameters,mCameraId,CameraHolder.instance().getCameraInfo());
        // Remove the video quality preference setting when the quality is given in the intent.
        mPreferenceGroup = filterPreferenceScreenByIntent(
                settings.getPreferenceGroup(R.xml.video_preferences));
    }

    public PreferenceGroup getPreferenceGroup(int preferenceRes) {
        PreferenceInflater inflater = new PreferenceInflater(mContext);
        PreferenceGroup group =
                (PreferenceGroup) inflater.inflate(preferenceRes);
        initPreference(group);
        return group;
    }

    private void initPreference(PreferenceGroup group) {
        ...
        ...
        
        ListPreference videoFlashMode =
                group.findPreference(KEY_VIDEOCAMERA_FLASH_MODE);
        ListPreference videoEffect = group.findPreference(KEY_VIDEO_EFFECT);

        // Since the screen could be loaded from different resources,we need
        // to check if the preference is available here
        ...
        ...
       
        if (videoEffect != null) {
            initVideoEffect(group,videoEffect);
            resetIfInvalid(videoEffect);
        }
    }

    private void initVideoEffect(PreferenceGroup group,ListPreference videoEffect) {
        CharSequence[] values = videoEffect.getEntryValues();

        boolean goofyFaceSupported =
                EffectsRecorder.isEffectSupported(EffectsRecorder.EFFECT_GOOFY_FACE);
        boolean backdropperSupported =
                EffectsRecorder.isEffectSupported(EffectsRecorder.EFFECT_BACKDROPPER) &&
                mParameters.isAutoExposureLockSupported() &&
                mParameters.isAutoWhiteBalanceLockSupported();


        ArrayList<String> supported = new ArrayList<String>();
        for (CharSequence value : values) {
            String effectSelection = value.toString();
            if (!goofyFaceSupported && effectSelection.startsWith("goofy_face")) continue;
            if (!backdropperSupported && effectSelection.startsWith("backdropper")) continue;
            supported.add(effectSelection);
        }

        filterUnsupportedOptions(group,videoEffect,supported);
    }

EffectsRecorder.java

    public static boolean isEffectSupported(int effectId) {
        switch (effectId) {
            case EFFECT_GOOFY_FACE:
                return Filter.isAvailable("com.google.android.filterpacks.facedetect.GoofyRenderFilter");
            case EFFECT_BACKDROPPER:
                return Filter.isAvailable("android.filterpacks.videoproc.BackDropperFilter");
            default:
                return false;
        }
    }

对于一些实现的库，比如android.filterpacks.videoproc.BackDropperFilter是在system/media下实现的。