Highest compression used without noticable quality loss?

[Yankee666666]

So far even on movies with high 50% compression I havent noticed much or any difference even on a 55" TV. Im having trouble deciding to reauthor or do a full backup on a movie that is 100% if i reauthor or like 65-70% if I do a full backup. Im leaning more towards full backup lately since I havent noticed much difference and it is nice to have all the extras. What are your opinions please.

[drewson99]

try it both ways, using RW media and see if they are both acceptable to you. if they are, go with the full disc backup.

[Thunder In Paradise]

I start to notice background quality loss at around 55-60% or higher. Fortunately, only really long movies like Braveheart and Dr. Zhivago get close to that.

[jimmalenko]

Firstly, quality is in the eye of the beerholder.

Good suggestion to use a RW, although could be fairly time consuming

My preference would be to do Full Backup if the extras are worth it, test the DVD and if its not up to your standard chuck it and do movie only. DVDR media is cheap enough these days to do this.

[Mattsensei]

Yes, anything below say 58% begins to show deterioration, especially in dark areas. But as someone else said, what one person finds unacceptable, another person will find fine.

[Vanderlow]

Also try a trial copy of Intervideo DVDCopy 2 Platinum and see what you think.

[jeremyp969]

It depends on the type of TV you have, on a plasma or tube TV you'll notice the quality breakdown at a higher bitrate then say with a projection. On my TV I can notice a degrading quality at around 85-90%. I usually stay above 90%.

[Jayhawk]

I agree with jeremyp969, on some movies I can't see a difference on my 84" DLP front projector but they are obvious on my 61" line-doubled Sony rear-projector. My cutoff is 85-90% on anything with action in it. Occasional chick flicks I'll drop as low as 77-80% but that's it.

[Yankee666666]

I agree with jeremyp969, on some movies I can't see a difference on my 84" DLP front projector but they are obvious on my 61" line-doubled Sony rear-projector. My cutoff is 85-90% on anything with action in it. Occasional chick flicks I'll drop as low as 77-80% but that's it.

What do you do then on movies that are like in the 60% range even when you do JUST the main movie? Do you split to to 2 DVDRs?

[Vanderlow]

FYI - in talking with a couple of joe six packs at he local store none had voiced any concerns over any movie they squeezed on a DVDr with one saying he has friends that put 2-3 movies on a DVDr. Obviously people have different standards.

[h8sh8]

Doesn't it depend on the orginal filesize too? Talking just about the video - minus all audio and extras, what if an original 2hr movie is 7gbs then compressed to say 3.8gbs would be at 54% but then a 4.5gb 2hr movie to 2.5gbs would be 55% - which would be better the higher % or higher filesize? I would have thought the higher filesize myself, or is the compression % in dvdshrink that much worse than what the studio authors use for the original?
Another example, is the movie 'Fallen' (R4 dvd) is 3.6 gigs for a movie going about 2hrs 10mins (including audio, and a commentary) - so if I compressed it even just 80% that would make it 2.88 gigs - seems damn small to me.
Does anyone out there go by filesize or only percentage?

[jimmalenko]

I have experimented with quite a few different configs for my DVDs.

Before I knew about DVD Shrink, I used IFOEdit to strip out unwanted streams and went to two DVDRs if I needed to. It was quite a lengthy process but did the job pretty well. I then found out about DVDShrink and absolutely swear by it now. I am not a big fan of extras or menus so I normally reauthor and remove unwanted streams. I have gone down to 55% and still been quite happy with the display on my 68cm TV.

At the other end of the spectrum I wanted to investigate the possibility of fitting 6 hours onto a DVD and wrote a GUI for my own personal use to batch the entire process. I ended up with bitrates around 1500kbps and I re-encoded to 352X288. The results were pretty good IMO.

[h8sh8]

At the other end of the spectrum I wanted to investigate the possibility of fitting 6 hours onto a DVD and wrote a GUI for my own personal use to batch the entire process. I ended up with bitrates around 1500kbps and I re-encoded to 352X288. The results were pretty good IMO.

Cool, so using that method, when dual layer burners come out, you could join all the extended LOTR movies back together as one 11hr movie and just keep the proper different credits from RotK on there - that's what I'm hanging to see done

[jimmalenko]

You certainly could. Would there be a need for credits ?

[Jayhawk]

What do you do then on movies that are like in the 60% range even when you do JUST the main movie? Do you split to to 2 DVDRs?

Yankee666666, Yes that's pretty much it. My problem is that if these are going to be real backups then I at least have to enjoy watching them. If not, then I'd rather take the chance the original won't get damaged, and if it does then just bite the bullet and buy another copy. With some of these older movies in the bargain bin at Walmart for $5.99 you have to ask yourself, "is it worth it". Two discs are such a pain and with dual-level coming inthe next few months I's almost rather wait on the longer ones. I can say that I have experimented with Green Mile (3 hours but no real action) and it's OK on smaller screen. Still, it's such a good movie I think if it got scratched I'd just buy another or trade for one at a "used disc" store.

[richdvd]

So far even on movies with high 50% compression I havent noticed much or any difference even on a 55" TV.

I notice a huge difference on a 43" Sony at 50%.
It is very pixelated.
Personally, I find 80% and higher is generally acceptable.

[djelimon]

For family guy (cartoon), I saw no difference at 60%

For Absolutely Fabulous, you bet I saw a difference at 60%.

My policy for shrinking - try it on a r/w if I must, and see if I like it. If I don't, reauthor. Currently I use DVD Remake, it's a good proggy.

[wolv6769]

Using DVD Shrink, and viewing on a Sony Flat Screen 36" TV, these are my limits:

Animation: 60% max

Chick Flicks: 70% max

Action movies: 80% max

Otherwise I notice the pixelation.

[bdf24]

I'm still pretty new to all this. But my preference is no less then 85%. I probobly would'nt notice it on my 36" RCA. But who know's I could end up splurging and getting a HDTV or Plasma some time in the future. So I'd rather back up all my movies with better quality now so I don't regret it later.
I do movie only as the movie is all I care about. I've never checked out the extra's and realy don't care for the menues. I'd rather throw it in and have it start instead of having to wait for the menues.

[h8sh8]

You certainly could. Would there be a need for credits ?

True, but the pictures of the cast were pretty cool on RotK

[h8sh8]

so no one knows if the compression quality is also dependant on the original filesize too, not just percentage? Seems weird to me if isn't - maybe I'm thinking about this the wrong way - I just thought a smaller filesized original would mean the original was compressed more than a larger filesize (by the original dvd author) - sorry to go on about it, but I can't understand how doing every movie at 80% will produce the same quality no matter what the original size (see my "fallen" example above) therefore making a judgement on the quality from dvdshrink by percentage possibly less accurate than going by the final filesize without audio - which dvdshrink also shows. Please tell me if I'm thinking about all this the wrong way - it's just that I'm a bit of a newbie and I've been doing it by filesize and may have unecessarily cut off extras when I didn't need to - cheers

[h8sh8]

Sorry to go on about it more, but another way to look at it...
Is the percentage in dvdshrink representing the percentage the filesizes are reduced, or the percentage of compression used (like a jpeg)?
If it's the second one, it's just that for example if I have a 245kb jpeg which was originally done at 80% (representing same as dvd authors compression) and then compress it a second time at 90% (representing our dvdshrink compression) the filesize is 345kbs - nothing to do with filesize, but it does reduce the quality further. So to me it seems dvdshrink percentage represents the filesize reduction - is that right?

Maybe this is why some people have such varied opinions on what is the best percentage to use. If the first movie I'd dvdshrunk was Fallen at 80% making it reduce from 3.6 gigs to 2.8, I'd probably think 80% was crap, but if I'd done a 7gig movie (with the same running time as Fallen) at 60% I may think 60% was great quality.

Of course what forgot to mention is the last post also was that running time needs to taken into account, so then would that mean going by filesize & running time is more accurate than by percentage?

Again tell me if I'm wrong so I can stop making a fool of myself before it's too late (though I probably already have done that)

[jimmalenko]

I just thought a smaller filesized original would mean the original was compressed more than a larger filesize

No. What it means is that the creators used a lower average bitrate in the first place.

The DVD Shrink % is the percentage of the file size ie. Compressed at 80% means the output is 80% of the original in terms of file size.

[jimmalenko]

Maybe this is why some people have such varied opinions on what is the best percentage to use. If the first movie I'd dvdshrunk was Fallen at 80% making it reduce from 3.6 gigs to 2.8, I'd probably think 80% was crap, but if I'd done a 7gig movie (with the same running time as Fallen) at 60% I may think 60% was great quality.

The readon people have varying opinions is because people have vastly different TV setups. 50% will look good on a 34cm TV. I have some at 55% that look good on my 68cm TV. Other people say that 80% looks crap on rear projections or projector setups. The acceptable % is determined by you and you alone because only you can comment on the output on your TV.

[h8sh8]

I just thought a smaller filesized original would mean the original was compressed more than a larger filesize

No. What it means is that the creators used a lower average bitrate in the first place.

The DVD Shrink % is the percentage of the file size ie. Compressed at 80% means the output is 80% of the original in terms of file size.

so does a lower average bitrate = less quailty than higher average bitrate? I assume it does, but if so then it would that still mean the higher average bitrate (larger filesize) one could be compressed at a higher percentage without being visible compared to the lower average bitrate (smaller filesize) making the filesize more accurate over percentage - is that right? or have I just lost the plot now? Don't know anything about bitrates really.

[h8sh8]

Maybe this is why some people have such varied opinions on what is the best percentage to use. If the first movie I'd dvdshrunk was Fallen at 80% making it reduce from 3.6 gigs to 2.8, I'd probably think 80% was crap, but if I'd done a 7gig movie (with the same running time as Fallen) at 60% I may think 60% was great quality.

The readon people have varying opinions is because people have vastly different TV setups. 50% will look good on a 34cm TV. I have some at 55% that look good on my 68cm TV. Other people say that 80% looks crap on rear projections or projector setups. The acceptable % is determined by you and you alone because only you can comment on the output on your TV.

yeah I get all that, but were wondering if this could also be factor - I've seen people with larger tvs say a low % looks good whereas people with smaller tvs say the same % looks bad. I realize that's it's also their opinions, but generally they are going on whether it's visible or not and I don't think their vision would differ that much would it - when it is noticeable it's easy to see (especially on transitions between scenes).
I mean regardless of percentage, the only movies it's been visible to me on (where the whole disc is at the same %) are movies (or total dvds) with a running time around 3.2+ hours (again running time & filesize) - that's out of 160 shrunk. Of course, I've also seen it where I only compress the crap out of menus or extras - but I'm talking about the total disc running time where I have no other option (other than 2 disc split). Seven Samurai for example, with only the movie on 1 disc.

[jimmalenko]

so does a lower average bitrate = less quailty than higher average bitrate?

In a word, Yes, but....
The birtates that are eing used are so high that you would not notice the difference of 8000kbps and 7000kbps. Technically one is better quality than the other but to the human eye they will look the same.

if so then it would that still mean the higher average bitrate (larger filesize) one could be compressed at a higher percentage without being visible compared to the lower average bitrate (smaller filesize) making the filesize more accurate over percentage - is that right?

Not always the case. The larger filesize can even be to do with more audio streams etc.

There is no real definitive answer to quality because it is a subjective measure. What is choice to me could be crap to you. THe best way is to do a few tests yourself at various %s using a couple of different movies (I would use 1 min segments of them) and burn these to a DVDRW to test for yourself.

I've seen people with larger tvs say a low % looks good whereas people with smaller tvs say the same % looks bad. I realize that's it's also their opinions, but generally they are going on whether it's visible or not and I don't think their vision would differ that much would it - when it is noticeable it's easy to see (especially on transitions between scenes).

This backs up exactly what I have just said. Peoples' measures of quality differ depending on how they backed the movie up and what equipment they're viewing it on. Someone may have brand name equipment which can do wonders with low % copies, while others have cheap shit which needs 90% to look good.

Read this. When you have finished the 150 or so pages get back tyo me if you don't understand it.

[h8sh8]

Sorry I think I was getting off track, but I'll put it this way (just read the top few paragraphs if you don't want to read it all)...

Movie with video only - no audio tracks - which dvdshrink shows the size of in the top-right area...

Is a 3gb movie better or same quality as a 4gb movie with the same running time?
and,
what if to get those filesizes, both were compressed by 60%?

Going by only percentage assumes they ended up the same quality.
Would it not be better the match the 2 filesizes, not the percentage?
ie
both 4gbs
one at 60% (originally 6.7gb)
the other at 80% (originally 5gb - at 60% would be 3gb after compression)

I think where it may get confusing (for me mainly) is if it reauthored as the movie only or if it's full disc.

Movie only, obviously is done at the highest % possible, and therefore people saying they wont go below a certain percentage would alternatively split the movie or not do it at all. People who dont care about that and want it on one disc, well then %, filesize etc doesn't come into account. The example above of a 3 gig movie would never be a problem, ie all movie 4.3gb, 4.7gb or whatever it is.

Full disc, this is where the 3 gig movie may appear (as has done so for me many times) - while 60% may look good on other discs, depending on the running time & filesizes, 60% may make the movie (no audio) drop to say 2.5gbs, other discs, maybe the movie would be 3.5gbs at 60% (because of total disc or movie running time and filesizes) - my theory is that the movie can end either up good or bad at 60% depending on the filesizes and running time. Forget that whether for the individual the actual number of 60% in real life ends up good or not - it's just an example. It is still going by you're own judgement on quality of course and tv brand/size, but all I am saying (in my theory) is that using the filesize and running time as a guideline will be more accurate than percentage (or course once you figure out what size is good for you).

Eg. (movie with no audio)
2hr movie @ 2.5gbs = bad quality
2hr movie @ 3.5gbs = good quality

3hr movie @ 3.5gbs = bad quality
3hr movie @ 4gbs = good quality

Who cares what percentage.

My theory is once you figure your quailty level out, you'll have a more accurate guideline for the compression amount.

NOTE: the above figures are off the top of my head and only an example.

Hopefully that makes more sense on what I'm talking about - it's only my theory - to me it seems logical, but I'll happily be the first to admit if it's wrong if someone can say what it is. Admittedly I don't know much about bitrates, though it seems to still fit in to me. The only thing I can think of (but I'm certainly no expert) that may stuff it up is different codecs (if they are used) - if a kick-ass codec makes an original at 4gbs look better than a different codec used for an original at 7gbs, this will surely stuff it up, though I don't think it would be that extreme, and it would also stuff up going by percentages anyway. If different codecs are used by big studios, I assume it would only be on older dvds compared to new ones where the difference would be noticable.

ok I'll stop hijacking this thread now - I'm very sorry, certainly not my intention - it just snowballed cos I can't explain myself properly

Thanks jimmalenko for the link too - bookmarked it to read later, looks to be very informative - cheers mate (always good to see a fellow aussies around)

[jimmalenko]

Is a 3gb movie better or same quality as a 4gb movie with the same running time?
and, what if to get those filesizes, both were compressed by 60%?
Going by only percentage assumes they ended up the same quality.

Percentage is to do with the filesize wholly and solely.

Assume both movies are 90 minutes long. Using the bitrate calculator here, 3Gb movie uses average of 4405kbps and 4GB movie uses average of 5963kbps. With these sort of averages it is unlikely that you could spot any difference at all unless it is a high action movie that requires a lot of bitrate all of the time. Do it and see for yourself. Re-encode your favourite 90ish minute video to roughly the bitrates I have described. Do 1 at 2000 min 4405 ave and 9000 max and one at 2000 min 5963 ave and 9000max. For most movies you will not tell any difference, I guarantee.

There is not always a mathematical answer to DVD Quality questions. Set yourself some rules of what is acceptable to you. My personal rules are:
1. Movie only - I'm not a big fan of the extras unless its a music DVD;
2. Strip unwanted audio out - I'm not planning on learning Portugese in the near future
3. If I'm > 85%, Shrink, no Deep analysis. If < 85%, use Deep analysis.
I am extremely pleased by the output this creates.

No Offence intended, but I think you might be trying to think about this way too much

[h8sh8]

No Offence intended, but I think you might be trying to think about this way too much

None taken man I had a feeling that could be the case - me thinking about it too much that is - I hope no one is annoyed at my inablity to wrap my head around some things - will definately check out that bitrate calculator, and look into bitrates more - don't fully understand, but I'm determined to nut it out now - thanks man, really appreciate the info.