I want to export (i'm using premiar / edius ) video at maximum quality but my target size have to be maximum 400 mb (the movie length its about 40 min. ) and if it can be lower then 400 mb its even better. what is the best way to export the movie so its will be quality and steel in a minimum size? (by quality i want something Hd or more if its possible , if not so the most quality i can get in this size target)
You will want to use the H.264 codec, as it has one of the best quality/filesize-ratios of all the codecs out there. For this codec, your file size (and consequently it's quality) is mainly determined by the bitrate settings.
Let's do the math:
40 min = 2400 sec 400 MB = 3200 Mb (Megabit) 3200 Mb / 2400 sec = **1.33 Mb/s**
So you can set your Maximum Bitrate to 1,33 Mbps and the Target Bitrate to the same value or slightly below that. Make sure to change your Bitrate Encoding to VBR, 2 pass for best results (this will take longer than exporting with 1 pass though). This is already quite low, with these settings you will probably get significant artifacts in your video. However, Youtube uses an even lower bitrate for it's video encoding (at least up to Full HD, not sure about 4k), so you could argue that people are used to it anyway. The amount of quality loss also depends on how much entropy (that is, small particles et c.) is in your video, watch this for an explanation.