Best quality in ripped clips?

September 17, 2010 6:56 AM

How do I get the highest possible quality when ripping clips from DVD's? I've been using AoA DVD Ripper software to make .avi files, and while some of them look just fine you can sometimes see a huge difference in quality. Should I be using different software or settings?

Free options are best, cheap ones are fine, any are appreciated. The clips will be shown on a projector. Sorry if this seems like a stupid question, I Don't know much about digital video.

posted by hermitosis to technology (13 answers total)

The best possible quality would be not to reencode at all and just crop the input VOBs appropriately into a newly authored DVD. Try something like MPEG Video Wizard.
posted by reptile at 7:23 AM on September 17, 2010

True widescreen DVDs are anamoprhic -- that is, they are stretched vertically so that they fill the entire (4:3) TV frame. This allows the film to have more vertical resolution. The DVD player reshapes them to fit the actual screen during playback. This is why DVDs actually look pretty dang nice on HDTVs.

So, when ripping such a DVD on your computer, there are two ways to undo the stretching: the software can shrink it vertically, or it can stretch it horizontally. The second is better, because you end up with a larger image with more of the original image data.

Make sure your software is doing the latter. The easy way is to simply check the width; it should be 800 pixels or so.
posted by kindall at 7:23 AM on September 17, 2010

What's doing the actual decoding? Are you encoding to something-in-AVI for decoding on a standalone DVD player, or through a PC?

If the latter, you're presumably not limited to certain codec/container combinations.

The "highest possible quality" from DVD is of course not to re-encode. However, achieving visual transparency between a DVD source and an encoded file is fairly straightforward.

Using x264, a free software implementation of the H.264 standard, through a front-end such as MeGUI, will allow you to take a set of VOB files ripped to your hard drive from a DVD and come out with an encoded file containing video, audio, subtitles, and/or chapter markers. I'm partial to x264 encoded video in a Matroska container with the original DVD audio and Subrip format (SRT) subtitles for reasons of space savings after encoding and flexibility at the container level.

MeGUI is also powered by Avisynth, which is an excellent frameserver with a huge variety of options for performing inverse telecine operations, deinterlacing, denoising, cropping, resizing, etc. video and also capable of performing audio operations. Ideally, you start with a normal retail DVD and are able to end up with an encoded file with black bars cropped, the original aspect ratio retained, the original film framerate restored, and all combing artifacts removed.

For playback, I like Media Player Classic Home Cinema with ffdshow and Haali's Media Splitter behind it. Using the Windows overlay renderer or similar should allow you to send this to your projector as a normal video out operation.
posted by Inspector.Gadget at 7:30 AM on September 17, 2010

FWIW, I'm not burning these clips back onto a dvd, just storing them on a portable hard drive.
posted by hermitosis at 7:31 AM on September 17, 2010

Most of the details in responses so far are over my head. I don't know enough about what AoA is already doing to explain anything, all I do on that program is select a filetype and aspect ratio.

Also, I won't be the one running the projector, and I don't have access to the computer hooked up to it. I just give them the clips.
posted by hermitosis at 7:37 AM on September 17, 2010

For a portable drive, and playback on a PC, x264 is the way to go for visual transparency and space savings. Also, I think correcting these misunderstandings would clarify what's going on when you rip and re-encode a DVD:

True widescreen DVDs are anamoprhic

All DVDs are anamorphic by definition because they don't use square pixels to reconstruct the correct image dimensions. If encoding to a situation where you need square pixels, you must resize all DVDs back to the original image dimensions or to another proportional size.

that is, they are stretched vertically so that they fill the entire (4:3) TV frame.

What? Widescreen NTSC DVDs are encoded at 720x480, and depending on whether your playback device follows ITU or non-ITU standards, are properly displayed either at ~854x480 or ~874x480. 4:3 resizing doesn't enter into it unless you have your TV set up to pan-and-scan widescreen content.

This allows the film to have more vertical resolution

You can't increase vertical resolution because there's no data there; you can only interpolate. It's generally better to hand off interpolation to your display unless you know that a certain software method (nnedi2_rpow2, etc.) looks better.

The second is better, because you end up with a larger image with more of the original image data.

No. The original image data no longer exists, because resizing and transcoding to create a DVD is a process that throws away information.

The easy way is to simply check the width; it should be 800 pixels or so.

It would be a rare widescreen DVD that produces an image at 1:1 pixel aspect ratio that looks right at 800px wide after cropping.
posted by Inspector.Gadget at 7:38 AM on September 17, 2010 [1 favorite]

Also, I won't be the one running the projector, and I don't have access to the computer hooked up to it. I just give them the clips.

Have they given you specific file type guidelines?
posted by Inspector.Gadget at 7:39 AM on September 17, 2010

Well firstly, .avi is not a video format, it's a container format. Saying you have a video in ".avi format" is like saying you have a document in a zip file. It tells us nothing about how that file is actually encoded.

Quality is a function of resolution, bitrate, and codec. If what you have right now is not of sufficient quality then increase the bitrate until it is, or select a different codec that can provide that quality at an acceptable bitrate.
posted by Rhomboid at 7:40 AM on September 17, 2010

(and framerate, but that's usually not something you can or should change.)
posted by Rhomboid at 7:42 AM on September 17, 2010

Have they given you specific file type guidelines?

No, they haven't.
posted by hermitosis at 8:05 AM on September 17, 2010

OK, then I would start here, BUT, since you're not working under specific directions, set up MeGUI to use x264 in "CRF" mode, and set the CRF value to 20. That way, you're not doing two passes to hit a specific size, and x264 will automatically adjust bitrate to keep the picture looking acceptably good. This will often save time and space, and is a good way to get your feet wet.
posted by Inspector.Gadget at 8:08 AM on September 17, 2010

I spent quite a bit of time trying to figure a lot of this out a while ago. I've been using Handbrake on MacOS, and found that using h.264 format works best, dual pass, the best quality de-interlacing settings, and making sure I check the video settings to I have the picture at the correct ratio (either compensating for anamorphic sources by stretching the picture, or NOT stretching the picture out of whack if it's a source which doesn't require it).

If you can find a copy of Handbrake 0.9.1, it will do the, um... decryption from encoded DVDs for you. If not, Handbrake 0.9.3 works great, and I think you can get it to couple with VLC for decryption, although I've never had much luck with that.

If you need to include multi-channel sound with your rip, the only good way is to use a .mkv wrapper, which will allow you to include anything more than stereo in your video package.

Also, I tend to try to rip to pretty high picture quality... 720p, usually. This means that the file size will be large, but looks great.

Understand, at these settings, video takes a LONG time to process. But if you play with the settings a bit (and read the online documentation which will be linked through Handbrake), you can probably figure out a group of settings that work best for you.
posted by hippybear at 4:01 PM on September 17, 2010

Also, I tend to try to rip to pretty high picture quality... 720p, usually

Upscaling DVDs is a waste of bits for the transcoded file. Without even considering artifacts introduced by the upscaling itself, there's no data: 480 lines of vertical resolution is all you get out of NTSC DVDs; the rest must be interpolated, which can be done with a variety of speed/quality trade-offs but in every case can be done on playback on your display or even with assistance from ffdshow/avisynth.

If you need to include multi-channel sound with your rip, the only good way is to use a .mkv wrapper, which will allow you to include anything more than stereo in your video package.

Matroska is a container format. You can put many things in it. You can also put multichannel audio in AVI, ASF, OGM, MPEG System Stream, MPEG 2 PS + TS containers, etc. I happen to prefer Matroska based on flexibility, but your container format almost never (unless part of an integrated proprietary standard) dictates how many channels of audio you can have.

or NOT stretching the picture out of whack if it's a source which doesn't require it

All DVDs are anamorphic. You need to either resize the frame or set non-square PAR or DAR flags on all rips.
posted by Inspector.Gadget at 7:22 PM on September 18, 2010