sample size of STSZ table in MP4

[jingke2000]

Hi All,

I've got 2 questions regarding the sample size in MP4:
1). Is it possible to get the VLC encoder (both H.264 and AAC) to output fixed sample size for MP4? Per the MP4 format spec, I can put a fixed sample size in STSZ table. I'm just wondering how I can do that with VLC.
2). If the answer to 1) is NO and then the sample size would fluctuate, can I use "skip" or "free" type to pad each sample so that I can still use the fixed sample size in STSZ table?

Thanks for any suggestions or comments.