帧率控制

g_sensor_fps 为sensor帧率，此帧率为恒定值

penc->m_context[channel].encconfig[entype].framerate 此帧率为所需要帧率

penc->m_context[channel].frame_cnt[entype]初始为0

sensor数据输入

            penc->m_context[channel].frame_cnt[entype] += penc->m_context[channel].encconfig[entype].framerate;
            if(penc->m_context[channel].frame_cnt[entype] >= g_sensor_fps)
            {
                penc->m_context[channel].frame_cnt[entype] %= g_sensor_fps;
            }
            else
            {
                continue;
            }

h264编码按需要帧率编码