H264/ASF stream out problem with timestamp

[viperking]

Hi,
I'm using VLC 1.0.2 to stream out the H264 encoded stream file with ASF packet.
And I found that in the result asf stream : the timestamp(presentation time) in some continuous payloads(same stream id, but continuous media object id) were the same. (means that different frames have the same timestamp?) . This result have really bad effect on my subsequent process.So do I need to change my VLC settings to fix this or what else?
Thanks very much for your help!