Image Quality with CBR or multipass [Archive]

Miket019

31st January 2003, 02:38

Ok finally after five days of waiting here goes my first question, I know most of you are super super expert and all but can you really see the difference from CBR mode to a Multipass mode with CCE? I understand that all the science behind it points to yes, but I have a 52inch panasonic and with most of my movies below 3hours and I have done both steps and the difference are so small I wonder why anyone would want to waste time with multipass???

PS: please don't tell me numbers or statistic but just tell me if you see a real difference and on what movie.(not a 5 second water scene in a 2 hour movie please)

thanks a lot guys and this is a really cool site

waldok

31st January 2003, 15:13

Please do a search in the forums about it, there has been numerous discussions about why using multipass VBR, why using CBR.
Particularly in the CCE and DVD2SVCD forums.

Now, I would say it's not a problem of seing any difference. CBR is cool quality wise, but every piece of the action is encoded with the same amount of bits (hence the name COnstant bitrate) : whatever kind of scene you have, you'll get your fixed amount of bits devoted to encoding this scene. This can be awfully space consuming and will require more room to fit a given movie on discs.
Now, the interesting thing with VBR multipass, is that it will first consider the "nature" of the scenes to encode, so that it won't waste bitrate on "easy to encode" scenes, and use higher bitrate to provide better encoding of difficult ones (like fast moving action for example). All in all, you might save a lot of space depending on the global nature of the movie you encode.
Now if you don't care about space, using CBR encoding and setting bitrate to the MAX supported value will give you the best quality and a bunch of discs. You're on your way to 7.8 GB, thus 2 DVD-R (audio and video streams only, you have to add MPEG2 Program data and all the annex vob ifo and bup files) for a 1h30 movie (correct me if I'm wrong).Considering the price of DVDR, I doubt it is the best solution to use.

But do a search, you'll get many opinions from many people about what they prefer to use. I personally stick to 1 pass VBR with some enhanced clever method set up by BAch

See this thread (http://forum.doom9.org/showthread.php?s=&threadid=41033)

Hope this helps.

Waldok :cool: