Div zero?

[QiAnXinCodeSafe]

Hi all,
This is Qianxin CodeSafe Team, we found a suspicious div-zero, at

openh264/codec/processing/src/adaptivequantization/AdaptiveQuantization.cpp

Line 192 in 3668daf

m_sAdaptiveQuantParam.iAverMotionTextureIndexToDeltaQp = iAverMotionTextureIndexToDeltaQp / iMbTotalNum;

in the maco used at

openh264/codec/processing/src/adaptivequantization/AdaptiveQuantization.cpp

Line 145 in 3668daf

iAverageMotionIndex = WELS_DIV_ROUND64 (iAverageMotionIndex * AQ_INT_MULTIPLY, iMbTotalNum);

and

openh264/codec/processing/src/adaptivequantization/AdaptiveQuantization.cpp

Line 146 in 3668daf

iAverageTextureIndex = WELS_DIV_ROUND64 (iAverageTextureIndex * AQ_INT_MULTIPLY, iMbTotalNum);

which is defined at

openh264/codec/common/inc/macros.h

Line 132 in 3668daf

#define WELS_DIV_ROUND64(x,y) ((int64_t)((y)==0?((x)/((y)+1)):(((y)/2+(x))/(y))))

the second argument y of macro WELS_DIV_ROUND64 may be zero.
which means iMbTotalNum may be zero.
so at

openh264/codec/processing/src/adaptivequantization/AdaptiveQuantization.cpp

Line 192 in 3668daf

m_sAdaptiveQuantParam.iAverMotionTextureIndexToDeltaQp = iAverMotionTextureIndexToDeltaQp / iMbTotalNum;

while dived by iMbTotalNum, a check against zero should be added.