First off, don't replace Vegas with After Effects. After Effects IS NOT a video editing program. It is a compositor. These are two very different things and shouldn't be confused. Most people will do all their basic editing in Vegas/Premiere then export clips or their entire timeline into AE for effects work. If needed, they will then export that back into their editing program. You can make an entire video using only After Effects but never treat it like or expect it to be a video editing program.
Now, lets answer some questions here...
setMosaic wrote:• How do I use the timeline on the AE as a trimmer like on Sony Vegas? I know how to split cuts and those things, but it seems on AE you have to do such a hard work to accomplish to find the scene you want and split it, I took 25 minutes just trying to do this, yeah, noob;
You can't. There's no trimmer and no Razor tool. The best way, if you really want to do everything in AE, is to do all your clipping in another program like VitualDub, export to a lossless codec like UTVideo and import that into AE for use. It's a little more time consuming but it's a lot easier to find the scenes you want.
setMosaic wrote:• Which extension it's better for editing on AE? I mean, for the episodes, I generally download '.mp4' raws from torrent episodes, 'cause I have no patience for converting 25 episodes of '.mkv' to '.avi', just, no;
If you have no patience for converting, then why ask? I highly advise you use UTVideo while editing. Using H264 encoded mp4s is unreliable unless you know what you are doing and encoded it yourself. Even then, it would be easier and faster to encocde to lossless.
setMosaic wrote:• Better rendering settings for AE? I was using pure '.mp4' (29fps, 32 bit pixel range) rendering on Sony Vegas, then I jumped right to '.avi' with logarith lossless codec (23fps[should I change that?])> Zarx264gui. I want to know if on AE this is option it's available, though I don't really know if it's the better one;
General rule of thumb is ALWAYS stick to the source. This means if your source is 29.97fps, your output will be 29.97fps. This is universal across all programs. Never change it unless you know what you are doing. The other rule of thumb is always encode out of the program lossless (Lagarith, UTVideo, etc.). Never encode to lossy until you are ready for distribution. In which case, use Zarxgui.
setMosaic wrote:• For the preview music preview on AE, I'm really confused about this, how do I do it, 'cause I can't just click space bar or enter to check the preview of the both things (video too), which I wanted too much, damn Vegas, now I'm lazy...
Another reason why you don't use After Effects to do basic editing. There's no "play the timeline and play the music too" button. When you press the space bar or the play button, the program is attempting to render and playback the video at real time. It does not play audio. This is a composting program, audio doesn't need to be playing at this point. In order to hear the audio, you need to either rendering the workspace or do a ram preview. What this does is render the work space into ram and then plays it back, with audio. The best way to use this is to change the work space in and out point where you want to render and hit the ram preview button. if you're computer doesn't have a whole lot of ram, it may not be able to render out the whole work place. If this happens, it will stop rendering and play back what it can.
What I've done in the past, in my editing program (premiere), is create a "sync map" where I would create visual markers, usually a color matt that fades out or cuts out shortly after the synced tone/beat. Then I'll export and import it into AE so I have a blueprint of how where my cuts and sync targets are. I'll then do my editing and effects work based off that map.
I hope that helped. AE is intimidating at first but once you get the hang of it, it's a breeze. Just don't use instead of a real video editing program.