Don't understand encoder process

[satwar]

I have created a little project to start learning about video, namely to create a VCD from an AVI. I think I did a pretty good job by first extracting the AVI audio stream (AC3) to a WAV. Then I used MainConcept Encoder to create a VCD, using the original AVI as video source (encoded with XVID) and the separate WAV file as audio source.

What exactly happened during the encoding process? I think the audio is relatively clear, a WAV file was compressed to an MPEG, but how did the XVID video stream on the source AVI get decompressed and then recompressed as MPEG?

I realize that the resolution of VCD is quite poor (350 x 240) but I'm wondering how you control the size of the image on a analog TV set? Does the TV just draw a 350 x 240 sized picture on the TV screen. How much will the video fill the TV screen of a standard analog set?

Thanks in advance for your patience and understanding.

[fritzi93]

This might help:

http://forum.doom9.org/showthread.php?&threadid=63587

Although it's part of a transcoding FAQ, it gives a concise description of MPEG encoding. It probably wouldn't hurt to have a peek at the glossary <-- over there, for instance look up "compression", "codec", etc.

Good luck.

[edDV]

...
I think the audio is relatively clear, a WAV file was compressed to an MPEG, but how did the XVID video stream on the source AVI get decompressed and then recompressed as MPEG?

You are starting with a highly compressed XVID file (a form of MPeg4), decompressing it and then re-encoding to VCD MPeg1 at 352 x 240 pixels size (an older less compressed format that is specific to the VCD requirements).

I realize that the resolution of VCD is quite poor (350 x 240) but I'm wondering how you control the size of the image on a analog TV set? Does the TV just draw a 350 x 240 sized picture on the TV screen. How much will the video fill the TV screen of a standard analog set?

That depends on the VCD player (usually a DVD player). Most will play it at full screen by upscaling the image.

[Abond]

I realize that the resolution of VCD is quite poor (350 x 240) but I'm wondering how you control the size of the image on a analog TV set? Does the TV just draw a 350 x 240 sized picture on the TV screen. How much will the video fill the TV screen of a standard analog set?

Don't worry, it will be resized properly to fill the entire screen.

[lordsmurf]

Read this:
http://www.digitalfaq.com/dvdguides/capture/understandsource.htm#aspectratio

[satwar]

Read this:
http://www.digitalfaq.com/dvdguides/capture/understandsource.htm#aspectratio

Right on, I've struggled with the concept of non-square pixels before, thanks for the reference.