webRTC 读取帧保存为bitmap

public void onFrame(VideoFrame frame) {
    saveImgBitmap(frame);
}

    public Bitmap saveImgBitmap(VideoFrame frame){
        final Matrix drawMatrix = new Matrix();
        // Used for bitmap capturing.
        final GlTextureFrameBuffer bitmapTextureFramebuffer =
                new GlTextureFrameBuffer(GLES20.GL_RGBA);
        drawMatrix.reset();
        drawMatrix.preTranslate(0.5f, 0.5f);
        //控制图片的方向
        drawMatrix.preScale( -1f ,  -1f);
        drawMatrix.preScale(-1f, 1f); // We want the output to be upside down for Bitmap.
        drawMatrix.preTranslate(-0.5f, -0.5f);
        
        final int scaledWidth = (int) (1 * frame.getRotatedWidth());
        final int scaledHeight = (int) (1 * frame.getRotatedHeight());
        bitmapTextureFramebuffer.setSize(scaledWidth, scaledHeight);
 
        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, bitmapTextureFramebuffer.getFrameBufferId());
        GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0,
                GLES20.GL_TEXTURE_2D, bitmapTextureFramebuffer.getTextureId(), 0);
 
        GLES20.glClearColor(0 /* red */, 0 /* green */, 0 /* blue */, 0 /* alpha */);
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
        VideoFrameDrawer frameDrawer = new VideoFrameDrawer();
        RendererCommon.GlDrawer drawer = new GlRectDrawer();
        frameDrawer.drawFrame(frame, drawer, drawMatrix, 0 /* viewportX */,
                0 /* viewportY */, scaledWidth, scaledHeight);
 
        final ByteBuffer bitmapBuffer = ByteBuffer.allocateDirect(scaledWidth * scaledHeight * 4);
        GLES20.glViewport(0, 0, scaledWidth, scaledHeight);
        GLES20.glReadPixels(
                0, 0, scaledWidth, scaledHeight, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, bitmapBuffer);
 
        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
        GlUtil.checkNoGLES2Error("EglRenderer.notifyCallbacks");
 
        final Bitmap bitmap = Bitmap.createBitmap(scaledWidth, scaledHeight, Bitmap.Config.ARGB_8888);
        bitmap.copyPixelsFromBuffer(bitmapBuffer);
 
        try {
            File file = new File("/data/data/com.xxx.diagnose/files"+ "/test.jpg");
            if (!file.exists()){
                file.createNewFile();
            }
            OutputStream outputStream=new FileOutputStream(file);
            bitmap.compress(Bitmap.CompressFormat.JPEG,100,outputStream);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return bitmap;
    }