Tearing effect when using two 1920x100 15 fps h.264 encoder + one 640x480 jpeg encoder?

When using two 1920x1080 15 fps h.264 encoder at the same time, and encode an 640x480 jpeg at the same time, we'll see tearing effect from resizer easily? Is there any limitation for such case? Of course,we have use OSA_mutexLock(&vicp_imcop_lock) to make sue jpeg encoder  and h.264 encoder won't run at the same time. For safety,we even have Drv_reszLock() to make sure that jpeg encoder won't run at the same time as Resizer. Can anybody explain how to deal with such annoying tearing effect? Or how should I avoid such so-called bandwidth issue smartly?