avoid signed integer overflow (#3523)
avoid signed integer overflow (#3523)


GuangweiWang/openh264,GuangweiWang/openh264,cisco/openh264,mstorsjo/openh264,mstorsjo/openh264,cisco/openh264,cisco/openh264,mstorsjo/openh264,GuangweiWang/openh264,mstorsjo/openh264,GuangweiWang/openh264,GuangweiWang/openh264,GuangweiWang/openh264,cisco/openh264,cisco/openh264,GuangweiWang/openh264,mstorsjo/openh264,mstorsjo/openh264,cisco/openh264,mstorsjo/openh264,cisco/openh264