imgproc/v0.3.19

Fixes

use the bounded buffer for video stream

#956 by @xianshijing-lk

Before this PR, it uses an unbounded buffer for video stream, that will cause multiple problems: 1, video will be lagged behind if rendering is slow or just wake up from background 2, it will be out of sync with audio

This PRs provides options to set a bounded buffer for video stream, and use 1 buffer as the default option.