Compression and Conversion!

[scott_k2003]

Hi All,

Quick question about converting DVD rips and compressing. Im a little green to this so please excuse my ignorance.

If a dvd rip is lets say 4.5gb and you use a utility like AutoGK to convert to Xvid or DivX and use 100% quality setting the completed file size sits around 2GB. So in other words you have compressed or stripped roughly 2gb worth of data from the original source.

Now my question focuses around whether or not it is worth compressing and converting the original source .vob's to a divx, xvid, avi, mpeg whatever format if space is not a concern.

I cannot see how you would not lose a great deal of quality by practically cutting the file size in half. I do realize that this is cutting all audio tracks except english in my case when I tested, but do the additional audio tracks really consume that much extra space?

I am interested in how others are handling this. I have about 250 DVD's I am planning to rip to hard drive for my htpc setup and looking for some advice as to whether or not its worth all the time involved to compress and convert the original source .vob and .ifo files to a different format.

Thanks all for the advice and helping out this greenhorn in his endeavor into htpc.

[unskinnyboy]

There is a quality loss in conversion (from any format to any other format), but it may not be really evident if you set the quality to 100%. If disk space is not a concern though, like you said, you should just leave the VOBs as is. For 250 DVDs, that's going to be more than 1 TB, keep in mind. If you do choose to invest the time and energy to convert, the advantage is that you can pack more movies on that disk, or use the space you will save for other purposes. Ultimately, you'll have to make that decision, not us.

[Brother John]

If space is not an issue, I wouldn’t recompress. Even without thinking about quality the time needed to convert 250 DVDs is enormous.

Re-encoding to MPEG-4 (Xvid, DivX, x264 etc.) always removes information from the video, i.e. lowers quality. In fact, that’s true for every lossy format. However at HQ settings chances are you won’t be able to see the loss. And since MPEG-4 is more efficient than DVD’s MPEG-2 you can have significantly lower file sizes with comparable quality.

[cogman]

What they said. :) one other consideration you might have to take in is that compressing to h264 (the best compression currently available) also requires that you have a significantly more powerful machine to playback the material, where as MPEG2 DVDs can be played back on nearly any machine.

Don't get me wrong, my 1.4GHZ celeron can handle SD h264 video. but I don't know what situation you are in.

[foxyshadis]

What I do is mainly only compress dual-layer movies. Maximize gains for the time & effort spent.

You'll never get transparent quality out of AutoGK, in my experience, though it can get more than close enough for regular viewing. Just don't go wild on the denoising unless you want to have to rerip it once you start wanting that sharper look.

[Ranguvar]

I cannot see how you would not lose a great deal of quality by practically cutting the file size in half. I do realize that this is cutting all audio tracks except english in my case when I tested, but do the additional audio tracks really consume that much extra space?
Many people see a good 1CD rip of a DVD in Xvid format as perfect quality when viewed from a difference. Me, a 2CD Xvid looks identical to the DVD source almost all the time.

The reasons you can strip out so much are:
- Fewer extras (menus, audio, subs, games, etc.)
- The fact that MPEG-4 ASP is much more tuned for low bitrates and a much more efficient compressor at low bitrates generally than MPEG-2 (DVD).
- The humongous popularity of codecs like Xvid, leading to lots of development and squeezing out every drop of quality.
- The fact that a good bit of resolution can be removed from the DVD without really sacrificing quality.

And much more...

Test yourself, experiment with options, and see if you notice a difference :) Although it does sound like a normal rip and not re-encode is what suits your purposes.

[Doobie]

Cutting a VOB into a half-size mpeg4 results in so little loss of quality that loss of quality is not much of a reason not to do it. The advantages of doing the conversion outweight the advantage of keeping the VOB, unless you have special considerations.

[unskinnyboy]

Cutting a VOB into a half-size mpeg4 results in so little loss of quality that loss of quality is not much of a reason not to do it. The advantages of doing the conversion outweight the advantage of keeping the VOB, unless you have special considerations.If you read OP's original post, you'd see that he does have special considerations - disk space is not an issue, and the time needed to possibly convert 250 DVDs to MPEG-4. These are strong reasons not to convert, and just keep the VOBs.

[Doobie]

If you read OP's original post, you'd see that he does have special considerations - disk space is not an issue, and the time needed to possibly convert 250 DVDs to MPEG-4. These are strong reasons not to convert, and just keep the VOBs.

Sorry, I confused you with too much information. Just disregard that last bit about special considerations (which includes people who want redundancy in the video stream, mpeg2 compatibility, etc.). I didn't want my comment to be taken as universally applicable.

He didn't say hard drive space is not an issue (on the contrary, a desire to compress them indicates that you're wrong). With 250DVDs, hard drive space has to be an issue. Mpeg4 files are much easier to manage and play than VOBs. His concern was loss of quality which, as I indicated, shouldn't be a concern.

Batch converting to large files doesn't take much effort. I'd just cue up all the vobs in DR DIVX and walk away.