Best Quality Method to Convert DVD to AVI

[mjanspacher]

Back until September '99 CSS - Content Scrambling System - was considered secure, at least if the movie industry was concerned. But in late September 99 I read the small note at inmatrix.com that CSS had been broken. Although there had been many cryptanalysts telling that CSS was not safe and rather easy to crack it took rather long till it cracking actually happened. Later in '99 the MPAA learned of an utility called DeCSS which allows people to decrypt the vob files to your hard disk. It's important to know that copying DVDs was possible way before that. As soon as you have a software DVD player running you can copy any file on a DVD to your hard disk - but it will still be encrypted. However it might be possible to put the encrypted content on a recordable DVD and play it back without actually having to decrypt CSS. Soon after the MPAA learned of this utility, they started out sending letters like that to sites that were offering DeCSS. They pointed out that the DMCA would forbid circumventing CSS and therefore that utility would be illegal. Many providers complied to their demands and shut down websites offering the utility. On December 27 '99 the DVD-CCA - DVD Copy Control Association - launched a lawsuit in California against about 600 people worldwide who were offering DeCSS for download. In the first instance their motion for a preliminary injunction was denied but later on it was granted. That process made it widely know that CSS could be cracked and it was the first time that this was widely reported in the press. On January 15 2000 the MPAA launched a lawsuit against several website suing under the DMCA for circumvention of a copy-protection scheme. The motion for a preliminary injunction was granted on January 24. Later on the MPAA tried to expand to lawsuit to bar 2600.org from even linking to DeCSS.

That is just plain CRAP! I bought the DVDs, I paid good money for them, and I have the right to protect my investment - I have the right to create backups of the DVD files to view or archive so that the original DVD disks will be less likely to become damaged with repeated use. And anyone who doesn't believe in this right needs to move to a country like China or Cuba, where rights are considered to be privileges, to be given or taken away at the whim of the ruling dictators and their 'enforcement' agencies!

[celtic_druid]

Decrypting a DVD breaches the DMCA in the US and I am not sure that there is any definitive fair use bypass. Definatly there should be though.

Anyone who doesn't believe in that right, they probably work for the MPAA or similar or at least accept bribes from them.

[jagabo]

Sorry, I'm just repeating what the DivX codec said - 'Insane Quality' (or does this just mean you'd have to be insane to try to get good quality into an AVI file of that size? Hmmm...).

Those settings of the Divx codec effect the motion search precision. The effect on quality is very small once you get above the lowest quality settings. Anything above "Balanced" is usually a waste of time. If you work in constant quality mode (single pass, target quantizer) it's easy to see what effect the different motion search precisions have -- the output is always the same quality, but the more motion search precision you use the smaller the file will be. You'll see that Insane rarely gets you more than a 1 percent smaller file than Balance -- but it will take 4 times longer to encode.

I have used several bitrate calculators to attempt to come up with a useable file. For a 45 minute file to fit into 350Mb, the calculated bitrate is always between 800 and 1000. The 935 I was using is the result of two different bitrate calculators...

Well of course all calculators give about the same bitrate -- the relationship between bitrate and file size is simple: size = bitrate * running time. The reason you were getting slightly different values was because of varying audio bitrates and maybe a little padding that some calculators use (it's a pain if your file comes out a few bytes to big to fit on a CD, if that's your goal). But note, there's no way of predicting exactly what quality any particular bitrate is going to give you. Different video characteristics will require different bitrates to get the same quality.

I usually don't care about the exact file size so I use Constant Quality encoding. I pick the quality level I'm happy with and encode in a single pass. The file comes out to whatever size is necessary to get that quality.

[mjanspacher]

Decrypting a DVD breaches the DMCA in the US and I am not sure that there is any definitive fair use bypass. Definatly there should be though.

Anyone who doesn't believe in that right, they probably work for the MPAA or similar or at least accept bribes from them.

Just because the greedy lawyers have been successful in convincing a bunch of corrupt judges and law-enforcement personnel that this is 'the law' does NOT make it either lawful or ethical. The citizens of this country are still supposed to be in charge of their own destinies...and their own government!

[mjanspacher]

Jagabo - thanks a bunch for this info. It is very helpful to us 'newbies'! Helps us to understand what's going on, and why.

[jagabo]

mjanspacher, You are using 2-pass (or more) variable bitrate right? When going for small file sizes VBR will get you much better results than single pass constant bitrate.

Another thing to keep in mind: when you see decent quality DVD-to-Divx files from the web they rarely have a full 640x480 frame size. The larger the frame the higher the bitrate you will need to maintain image quality. Of course, you are trading off overall resolution to get fewer macroblocks.

Also be sure you disable the "honor 'repeat first field' flag" option in VirtualDubMPEG2 if your DVD is 23.976 fps progressive. This will prevent VirtualDubMPEG2 from creating 29.97 fps interlaced frames from the 23.976 fps progressive source. Fewer fps means you can use a lower bitrate (and you won't have to deinterlace or inverse telecine). The option appears when you check the "Ask for extended options after this dialog" option on the File Open dialog.

[mjanspacher]

Currently I am using the avi.NET software with fairly good results. I have increased my target file size to 450Mb, and the improvement in quality is quite noticeable. The only issue I am still experiencing is an occasional 'hiccup' in the audio of the finished AVI file - changing the target size has not effected this at all, as far as I can tell. It is a minor irritation, but since I have the original DVDs, it's no big deal - the biggest problem I have with this is figuring out what is causing it and how to resolve it.

As far as I can tell, avi.NET first extracts the AC-3 audio track(s) to a WAV file, then converts the WAV to an MP3 (which I assume is layered back into the finished AVI at some point). Maybe these 'hiccups' are caused by the program attempting to fine-tune the synchronization of the audio file and the video file? The video conversion is using two-pass, but that's all I can tell from the program (the rest is all brain surgery, as far as I'm concerned). I think it may be time to invest in a 'Video File Conversion Techniques for Dummies' book.

Jagabo, again your input is greatly appreciated. The point you make about the frame size is something I had not considered, but certainly makes sense. I have been attempting all of my conversions at full size, which will result in a larger overall file size in the finished product.

[abazabam]

Both are MPEG 4, part 2, codecs. Divx is a commercial version, Xvid an open source version. I think Xvid gives slightly better image quality (for a given file size). Divx is faster at its fastest (lowest quality) settings.

But since XviD is older and there are constantly new updates to DivX, would DivX have the same or better quality and compression by now?

[jagabo]

But since XviD is older and there are constantly new updates to DivX, would DivX have the same or better quality and compression by now?

I don't think Divx is spending much time improving the encoding quality. They seem to be concentrating on things like menus, chapters, and subtitles.

[celtic_druid]

Too late. DXN does seem to be puting quite a bit of work into DivX (the codec) and XviD hasn't recieved many updates lately, although it did get faster GMC last week. Fact is that the rest of the world, including XviD are moving away from MPEG-4 Part 2 to MPEG-4 Part 10 and other newer technologies. So if DivX overtakes XviD, it won't matter anyway.

[DarrellS]

So when is Philips going to start pumping out the H264 players and will they handle high definition files?

[meldavid]

By the time they release a stand-alone powerful enough to decode H.264, you may as well just get a Mac Mini or similar HTPC second-hand to be your main movie player... Or an X360 (once it's hacked to support Dolby Digital 5.1.)

[ram16]

Convert with Nero Digital then put a divx shell around it for you divx capable player your results well be far better than divx and it does a whole movie in around 90 minutes on 2 pass

Could you elaborate a little on your use of Nero Digital, please? For instance, do you have to buy the whole package (Nero 9) to get Nero Digital? Also, what do you mean by "put a DivX shell around it"? How exactly do you do this? If I sound ignorant it's because I am but I'm trying to get better.