MP4 video encoding (to reduce file size)

[stefi.quattro]

Hi everybody,
I have a video recorded by a camera and I would like to do the following actions:
1 - cutting video in pieces : the video contains different speeches and I want to divide them;
2 - encoding : since the videos must be uploaded on the Internet I need to compress them in order to reduce the filesize (for example it would be ok to reduce the image size).

I did the first operation (even if video and audio are not perfectly sync) but I don't understand which kind of format I can chose for encoding,

could you help me?

The video information are: 
Codec 4CC : H264, Image size  :1440*1080  , frame rate: 50.000fps
Audio
Codec: AC3, Channels: Stereo, Bitrate: 32000Bps/ 256 kbps, frequency: 48000 Hz

thanks
Stefania (Italy)

[styrol]

I did the first operation (even if video and audio are not perfectly sync).

h.264 is time based, to avoid AV sync issues use Avidemux 2.6.

but I don't understand which kind of format I can chose for encoding

Video: x.264 (use filter to reduce the image size)
Audio: AAC (stereo, 96kbps @ 48000Hz)
Format: MP4 (MP4v2)