H264 Hardware decoding

Currently doing a real-time video transmission and playback, now tune through video encoded using mediarecorder, then packaged sending rtp and receiving end is out of decoding library to decode, but this way there is a delay, delay for several seconds, the camera shakesevere delay  do not know there is no way we can be hard-coded, to minimize delay and screen playback smooth, hope master pointing or two, the other does not know mediarecorder collected video is hard of knitting or soft compiled when setting resolution640 * 480 or above, the video is more spent, it is not clear, I do not know that this is where the reason, thank you