What does this mean??

[Hatz]

Hey everyone sorry if this is isn't in the right forum but I have seen this terminology used in different forums so I don't know which to use.

My question is............I see all the time people talking about 2pass cbr/vbr
3 pass.........4 pass..........10000000pass.

What does these pass mean?

I guess I have seen it when people are talking about making VCD and SVCD but I would only be interested in what it would mean when capturing analog tapes. Does this have anything to do with it cause I thought I read a post where it did but they gave no information on what a pass means.

I'm sure this is a real newbie question but I would just like to learn for next time when I come across a post where they are talking about this.

Thanks.

Hatz

[Solarjetman]

It has nothing to do with capturing, it only applies to the encoding.

Lets say you want to fit the entire movie in 700MB. It is not an option to go any higher. Well, when you limit the file size, it becomes necessary to compress the video, and a quality loss is associated with this. However, scenes of a film that do not have lots of movement on the screen require less file space to encode without a large loss of quality than scenes that have lots of movement. The amount of file space used to encode the video is the bitrate.

In constant bit rate (CBR) the same amount of file space is used throughout the video. In the case of VCD, this is 1150kbs. However, if you use variable bit rate (VBR), the encoder searches through the video and finds scenes that need the extra file space and remembers them. It also finds areas that could do with less space and remembers them. Then on another "pass" it begins to encode. When it comes to the heavy movement area, it will raise the bitrate higher in order to compensate for the extra need. Then when it comes to the low movement areas, it will lower the bitrate in order to keep the overall size of the finished product from increasing.

The number of passes just describes how many times it analyzes the video finding the high movement and low movement areas. Generally the more passes, the better quality but longer time to encode.

[Hatz]

Ahhhhh thanks Solarjetman. That clarified things right up. I appreciate the help on this one. So if I'm burning to dvd since I have a dvd burner then I do not need to worry about passes and stuff like that.

Things are actually starting to make since now.........heheh Thanks again.

Hatz

[Faustus]

Ahhhhh thanks Solarjetman. That clarified things right up. I appreciate the help on this one. So if I'm burning to dvd since I have a dvd burner then I do not need to worry about passes and stuff like that.

Things are actually starting to make since now.........heheh Thanks again.

Hatz

Actually if you ever encode any video to burn to DVD then yes you need to worry about the passes. The good news is not that much... if the software your using has pass options 2 is usually enough.

[Hatz]

I don't know if my programs have that......for normal dvds I use DVDSHRINK and for movies that I edit from analog I use TMPGEnc to encode.

I suspect since these are both good quality programs that they have this??

Hatz

[Faustus]

You'll never see it in DVDShrink, but if you dig a little there are Pass options in TMPGEnc. Anyway its not much of a worry really.