[FFmpeg-user] how can i capture video and audio simutaneously?

[chao sun]

i have a webcam with mic, i can successfully capture video or audio
independently. But when i want to capture and mix video and audio into
one file, it goes that my video and audio does not synchronizing.
i use the following cmd line:

ffmpeg -f video4linux2 -s 320x240 -i /dev/video0 -f alsa -ac 1 -i
hw:1,0 -acodec libmp3lame -ab 96k camera.mp4

The result file, in which the video has very slow start( may be due to
encoding i guess), and then goes normally, the whole audio goes
smoothly as normal. So it results in video-audio mis-sync.
How can i solve this ?