Shrink/Recode - at what compression ratio would you do disc vs. just movie?

[bgc99]

At what compression ratio would you do a full disc backup vs. just doing the movie? I guess they both list it the same way, the value it gives is % of original quality right? So if it says 75% or 80% would you do the fill disc or just the movie always or what?

Thanks,
BGC

[yoda313]

That is totally up to user preference. Some people will compress a huge movie like Lord Of the Rings and keep everything not caring if it compresses down to 50%.

Others will insist on splitting to two discs so as not to ever compress it. Or step up and go to dual layer for a 1:1 (pricier and less compatible option than single layer).

Personally if its a hour and a half movie I tend to do a full backup and not care about the compression rate (I only have a standard tv not high def tv). If its two hours or more I often do a movie only backup and take out the extra soundtracks - maybe leaving a commentary track in.

It's all up to personal taste so there's no hard and fast rule.

[BSpielbauer]

At what compression ratio would you do a full disc backup vs. just doing the movie? I guess they both list it the same way, the value it gives is % of original quality right? So if it says 75% or 80% would you do the fill disc or just the movie always or what?

Thanks,
BGC

The above response is 100% on the mark. And, if you want more detailed info, do a search, as this is one of those questions which has been dealt with again and again, and almost has been "beat to death."

The criteria you mentioned ("at what compression ratio?") is not even a decent barometer. In some cases, that compression ratio is including lots of extras, animated menus, coming attractions, etc. In other cases, it may only be including a main movie. Some of the most recent copy protection schemes are now inserting corrupt video or unreferenced video, and this can also complicate the issue a lot, since it can affect the amount of material you might be including to start with.

A FEW of the the other issues... 1) size of display. What looks fine on a 19 inch monitor might look horrible on a 65 inch display, or a 108 inch front projection system in a home theater.

2) Quality of display... A high definition set, especially one which has been ISF calibrated, is able to show you every fine detail, but this means it can also show you every flaw and artifact, where a standard definition set might not even be able to resolve such problems.

3) Your own individual level of acceptability... I am picky. What looks "good enough" to my wife often looks terrible to me. And, there are times when she complains about the video quality, but the kids swear it is just fine.

4) Remember that some DVDs use a higher bitrate to start with, and this can make a HUGE difference. So, if a software program reports a compression rate will be used that is 75% on one DVD, this often is miles away from the next time it will report a compression rate of 75%, simply because of the bitrate used for the original commercial store-bought DVD (which often can fluctuate a lot throughout the actual programming, from scene to scene, and even from moment to moment).

5) Remember that a film can vary a lot from one shot to the next... Action scenes and quick camera cuts and fast camera pans will suffer much more from compression than a placid, slow, graceful scene with little camera movement.

I could go on, but a simple search will yield similar issues.

-Bruce

PS-- I simply split all dual layer discs to two blank DVD5 discs, or else I purchase a DVD9, to avoid woryying about such issues. This makes my backups equal to the original, as far as compression, and it keeps me from worrying over the "how much is too much" debate.