DVD Shrink Compression : 2.0 vs 2.2

[Yesod]

I did backup Die Another Day with the two versions. I only did remove the french sound tracks and a few subtitles.

With 2.2, the disk size was closer to the full disk capacity than 2.0 so I thought : "great! more space -> better picture quality".

Unfortunately this was not the case : 2.2 gave an ugly result, the picture quality was worse by far :(

Has anyone experienced the same issue ?

Is this better with 2.3 ?

[Llama]

Yes, I have noticed the same thing. The other day, I did a main movie only backup of "Catch Me if You Can." I did it in 2.0 first. I did it at compression level 1, which was 30%. I decided to try it on 2.2. For 2.2, I had to go to compression level 5 or 6 to attain 30% reduction. The quality was a good deal worse.

At first I figured that 30% is 30%, no matter what the actual compression level is. However, I have read since then that 2.1+ uses a whole different transcoding engine. It does some funky dynamic stuff, apparantly. I think 2.0 had a very rigid set of rules for each level of compression (which allows for fewer levels of compression, but better compression on some levels, apparantly).

At any rate, more levels of compression is good and all, but the quality at 30% should be the same (or better) in 2.1+.

I had planned on running more tests today. I want to try to get some screenshots to make sure I'm not smoking crack. I may or may not get those done today though.

[int 21h]

Originally posted by Llama
...At any rate, more levels of compression is good and all, but the quality at 30% should be the same (or better) in 2.1+...


This is like saying that the level of compression between two distinctly different programs should be the same. The old engine had all kinds of quirks (like pulsing from the compression of one-two-or-three frame types) that the new engine has eliminated.

Not only that, but you're both talking about movies that are well above 120 minutes long. Ponder for a second what the conventional transcoding bitrate to a DVD-5 would be, and you'll soon see that using a compressed domain process on movies this long is a bad idea.

Compressed domain encoding works well some of the time, but on longer movies, or on discs with alot of extras, you'll definitely want to consider a different method.

[Llama]

My point is the movie looked great the first time around (with 2.0). There were a couple of little things that could have been better, but as it was a 2 hour movie, I thought it was great considering. Now, with 2.1+, it looks like crap. I was thinking that the types of transcoding might need to be mixed up a bit. I.e. keep the new transcoding for all of the < 30% compression levels and maybe go back to the older way of transcoding for the > 30%.

Having said that, I haven't tried the different versions for that many movies. It may well be that for most movies, 30% looks better in the newer versions than in 2.0. If that is the case, then obviously the method that is working for more instances needs to be used. However, if 2.0's 30% compression level is consistantly better than 2.1+'s, then maybe some mix and matching can be done. I don't know what the code looks like though, so that may be easier said than done.

Personally, I use CCE for the most part. I just like to fool around with new stuff as it comes along to see if it's worth messing with. I will continue to try DVD Shrink and the various levels of compression. Like everyone else here, I hope it gets better and better. I just feel that it's worth noting the quality drop in certain instances.