Sign in with
Sign up | Sign in
Your question

11 times compression & almost perfect quality!?!

Last response: in Apps General Discussion
Share
March 19, 2002 10:51:20 AM

I read the review of Divx 5.0 and enjoyed it, though I still can't get my head around the suggestion that a DVD can be ripped and compressed almost 11x without losing quality! How is this done? The smallest I've managed to get a movie (112 mins) is 1.4Gb, and even then the quality wasn't that great.

I'm using FlaskMpeg - should I be using something else? What sort of compression are you guys getting?

Cheers,

Si.
Anonymous
March 19, 2002 1:38:00 PM

I wonder who was the person doint the quality evaluation.
He probably don't know video from audio.


Intel / AMD - <A HREF="http://www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>
March 20, 2002 10:41:23 AM

Out of curiousity, and I know everybody has different ideas about quality, but what is a reasonable compromise between size and quality on a 2 hour movie? Should I be looking at 1.5Gb, with decent quality and be happy with it?

Cheers,

Si.
Anonymous
March 20, 2002 2:08:03 PM

The quality Vs. size is a personal preferances in most cases.
One person will acceppt a lower quality video while other will call it Crap.

Intel / AMD - <A HREF="http://www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>
March 22, 2002 5:47:48 AM

I was using flask for several months, then I tried Gordian Knot and never looked back. You can do variable bitrate control of your compression and get 45-60 minutes of high quality video on a 700 MB CD. You can also dictate your final file size very acurately.

Check out Doom9.net for all the downloads and very good how-to guides.
Anonymous
March 22, 2002 7:31:10 PM

You can't put 60 min of high quality video on a 700MB CD-Rom even if you will stand on your head and flap your feet while encoding.
Not even with Snell & Wilcox Pre filters on D6 video material captured using a Video Toaster card at 4:4:4

It's all a personal preferances of quality/compression Vs. Quality.

Intel / AMD - <A HREF="http://www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>
March 22, 2002 8:56:50 PM

Have you even tried GKnot?
March 23, 2002 6:38:18 AM

You must be a very picky person or not know what you are talking about. I put movies up to about 2hours on one cdr with very good quality. True some movies do not code as well. The most troulblesome have been porn (because everything on the whole screen is bouncing up and down all the time) and home movies where the camera is never still. Normal Hollywood shows look way better then vhs, way better then dish network tv, and almost as good as a dvd when compressed with Fair Use and divx. For hard to code movies or movies over 2 hours 2 cdr disks are required. Also to get a movie down to that small of a file size 6 channel dvd sound is compressed to 2 channel mp3 sound. This saves a ton of space. Now everybody reading this keep in mind that I'm talking about home use here, I'm not running a broadcast studio here and maybe I'm not very picky but I'm telling you that most people can not tell the difference between my backup copies and a dvd. There is a difference and it is very noticable on a monitor but is very subtle on a tv. If you zoom in a dvd will look much better then a fu/divx copy but unzoomed at at normal viewing distance the fu copy looks very good.

Remember if you ain't Muslim you ain't Shiite.
Anonymous
March 23, 2002 5:47:56 PM

I have triad video encoding from varius sourses with several programs and diferant settings.
Then I tested them on a Class A professional grade TV monitors in our studio, and let more people that are more professional then me in evaluaton of video quality to give openions.

Basicaly you don't know how to evaluate the quality.
There are lot's of things and types of artifacts to look at.
If you get even one blocky Quantize area then the video automaticley get '0'.
there are diferant types of noise to be looket at and more.

You Can't put high quality of video on a 700MB cdr.
you can get very nice quality and watch it in plasure knowing that you beat up the system.
But I will still go for the "original"


Intel / AMD - <A HREF="http://www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>
March 24, 2002 1:20:48 AM

Well that explains a lot. You are picky, as is your right. As I mention in my post a highly compressed movie will look bad on a monitor. In fact even a dvd even looks like crap on a monitor because a monitor is sitting right in front of you and because monitors have higher resolutions then tvs do. What I was talking about is playback on something like a 32" tv like a lot of people might use to watch a movie or show. I agree that a highly compressed video is not as good as the original but at the same time the quality beats vhs tape and beats dish network programs. A tv blends and softens a picture so on a tv the jaggy lines are smother, the blocks are blended and the sharpness is not so important as it is on a monitor.

"Basicaly you don't know how to evaluate the quality"

I wish this were still true and so does my buddy Bill. Since I have been doing divx compression and getting better at it we both notice a lot of errors in programs. In the past I thought that digital dishes had perfect pictures but now that I know what to look for I see microblock in everything (except analog sources and they have their own issues), even dvds have microblock (at a much finer level). As long as you are not looking for it you don't see it but once you see it you can't stop seeing it.

To enjoy a show I need to concentrate on the action and not looks for flaws. I you look you will find them. I wish I could have you over and show you and maybe one of your friends (who doesn't work in a studio) my work. You might think my stuff looks like crap but your friend is not going to be able to tell that I'm playing 650MB file off my hd and not a dvd. It really depends on how picky you are and how much money you want to burn up. I can burn a decent quailty movie on a 50 cdr that is way better then anything you could record on a $1.99 tape and you don't need to rewind. If you want to be able to erase it all you need is a 79 cent cdrw. The quailty may not be perfect but it is better and cheaper then tape. You can get anywhere on the disk in seconds and pause is jitter free perfect. Also to copy a tape takes as long as it does to watch it but I can copy a disk in minutes.

Sorry if I was insulting in the last post, I'm pretty proud of how good of a job I do. Learning all the programs it takes to really do a good job is no small task.

Remember if you ain't Muslim you ain't Shiite.
Anonymous
March 25, 2002 9:34:17 AM

As it was said, Quality is in the eye of the beholder.
It's a highly subjective thing and yes, I agree, working in a studio and having a over 5K DVC-Pro VCR makes you snobish and picky as hell.

If you ask me, most of my clients will not see a diferance betwin Hi8 tape that was sitting on the shelf for 5 years and a new DVC-50 even if I will stuck there heads into the monitor and tell them what to look for.

Also as said, it's a question of what you are going to do with it.
If you are going to watch your video on a computer, DviX is a very good valid solution. But blowing it to TV and espacially the big monitors will resoult in less the quality that I personally am willing to accept.

Also there is a big question of how the video was encoded.
Many mistakes are done at this stages that reduce the overall picture quality and the people encoding don't even understand that they are doing wrong.

I maneged to make mpg1 files with quality close to VHS. My client who got the CD with it was more then happy and that is the important thing.
To be happy and enjoy your creation :o )

Intel / AMD - <A HREF="http://www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>
March 25, 2002 4:37:04 PM

Additions and corrections to my posts.

There are other factors that limit the ability to squarsh a show to a cdr in (what I call) acceptable quailty. The easiest is a wide screen, mostly still camera, film that was originally coded to 24fps source. If the source is full screen you have almost twice as many pixels to encode and twice as many for you poor cpu to decode. Full screen movies are harder to fit on one disk. Also if an original was recorded at 30fps and is not teleclined it will need to be compressed at 30 which is harder then one done at 24fps. Most movies are wide screen and most started at 24fps and were expanded to 30fps when put in a dvd. These movies can easily be reconverted back to the original 24fps with no loss in quailty or smoothness, so they will take up less space. Even by my less picky standards it is impossable to compress a 2 hour movie to a single crd if it is full screen and the original is 30fps and there is a lot of action or camera movement.

Remember if you ain't Muslim you ain't Shiite.
Anonymous
March 26, 2002 8:01:09 AM

Actually,

Encoding PAL that is 25 Frames Per Second and NTSC that is 30FPS in full screen resolution is just the same. reason is that PAL full resolution is 720px X 576px while NTSC is 720px X 480px.

Width screen is exactly the same as normal. It's just that the pixels in width screen are streached. It's still the same 720 X 480/576.

Telchined material is another thing.
As it was filmed at 24FPS it's teoretically best to encode it at such.
When encoding the professional way they are using special Pre-Filters that can "Clean" the field duplication created by the telchin and save data.

Resizing the picture at any stage and espacally capturing create another problems. The CPU have to "Scale" the video while play back and the Overall picture quality is being reduced and made much less sharp. (look like water on the video).

Intel / AMD - <A HREF="http://www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>
March 26, 2002 1:10:23 PM

Scuba,

I have a question for you


I shoot with a mini dv jvc camera, (it states on it 520 horisontal lines, but I guess its 720 by 480 ??)
and I use premiere to inport the file via fire wire...

so I have a movie (avi file) on my hard drive whitch is insanely large -few gigs.

well anyway, this is a thing about me, I am like you, I've done photograpy all my life, and quality is what I care about, I dont want to sacrife quality more than 1%~~~~~ :eek: 
It doesnt look good to begin with (to me that is, b/c I want megapixel resolution), so I definatelly dont want to cut it even more.

My problem is I have to convert/encode/dicode( still reading up on this stuff),
well I have to do something to make the file size smaller.

I want to fit between 20 and 30 minutes on one cd-r

right now leaving the data raw (the way it imports from camera to premier), I fit about 2-4 minutes :eek:  :eek: 

what would you suggest in my situation,

and again I have been reading a lot on http://www.divx-digest.com and doom9.org
but they have so many gazilion ways to do everything, I'm just not finding/ not sure of what will work for
what I want.

any help from anyone would be appriiated.


my 2 rubles.
Anonymous
March 27, 2002 9:22:44 AM

First edit your material using the DV codecs. This way you preserve most of the quality as you can during editing stages.

Then you need to encode your video from DV codec to another codec to save space and being able to put it on the CDR.

Main question is WHAT is the CDR be used for.
If you want to still watch the video on a normal DVD player then you have to choose betwin VCD and S-VCD. Depend on your DVD Player.
If it's just for backup on CD's and you will watch it n the PC then I recommend using the new DviX 5 codec, but make sure to use high quality settings when encoding.


Intel / AMD - <A HREF="http://www.llnl.gov/asci/news/white_news.html" target="_new">IBM are still the best</A>
August 6, 2002 1:36:52 PM

Ok, I've made 2-hour 704x528 MPEG1 VCDs using VBR and on the TV they look nearly as good as the DVD. Unfortunately, many DVD standalones won't play them. Seems the less-known the brand is, the more likely it will play anything you throw at it. Any friends going out to buy a DVD player, I give them one of these and tell them if it won't play this, don't buy it. Quality is indeed in the eye of the beholder. If you're that fussy, you should just stick to buying DVDs. For me, if I can get a 2-hour movie onto one CDR at at least VHS quality, I'm happy. There are lots of things that make a movie hard to compress. Letterboxed movies are easier because you can mask off the black bits and replace it with blanks, so you've got more bits available for the actual picture. Film grain and video noise are difficult; I can never get a captured VHS movie to compress as well as from a DVD. Constant movement is very bad. Waterworld gave me nightmares. If you want something to develop your talents, try Waterworld - probably the least-compressible movie ever made. (it's all on the water, so nothing ever stays still) I had to settle for a little bit of block artifact, there was just no way around it. So, anyway, perfectionists should go find another tree to bark up. Why do we do this? Because we can. Don't tell me a 2-hour movie won't fit on one CD. I've got dozens of them.
bernie
August 7, 2002 12:18:27 AM

vcdhelp has a compatibility list that can help you find dvd players that will play vcd/svcds. Make sure to also check if it will play cdr/rws as this is a seperate issue. A vcd on cdr is different from a store bought pressed vcd. Some players can play vcd but not cdr. Click on <A HREF="http://www.vcdhelp.com/dvdplayers.php" target="_new">http://www.vcdhelp.com/dvdplayers.php&lt;/A> for the list.

Looks like the Yelo 800 (?) plays everything.

Give me fuel, give me fire, give me that which I desire.
August 7, 2002 7:36:37 AM

I have something to say about the 'quality' issue. So everybody stand up and listen.
Firstly, i havent thoroughly read all the above posts, only skimmed them.
Secondly, i have absolutely no authority on the subject, Other than 28 years of watching much TV.
Thirdly, and possibly the only thing of relevance, "good quality" means a certain quality that looks good. To you. And in my book thats how its going to stay.

When i started encoding Video CD, i had a resolution of 352 x 288 (PAL world here) and as soon as i played the discs on a TV i thought "bloody hell they look great". Moving to DVD was "bloody hell it looks great". When i move up to HDTV with blu-ray DVD's it'll be the same.

But the issue is so subjective.
What i do feel is that
1) An encoded film will look better on TV than on a computer monitor due (i think, at least in part) to the larger phosphor emissions of the pixels. Or something like that. Sure, a computer monitor is much much sharper, but thats not a positive thing always.
2) You really can get away with lowering the resolution from the 1000 x 1000 image you started with.
3) But keep your quality, resolution and file size as high as possible until the very end stage (ie encoding) if you are editing, to minimise any additional losses.
4) I think that a slightly 'blurrier' image, ie lower resolution but smooth works better than a sharp but jerky image.
5) And its also better than one with artifacts or "blockiness" where you can visibly see squares appear on the screen, often due to not having a high enough bit-rate for your resolution.

So there we have it. The definitive word on quality. For me anyway.

<A HREF="http://www.anandtech.com/mysystemrig.html?id=19557" target="_new">http://www.anandtech.com/mysystemrig.html?id=19557&lt;/A>
!