vc-1, mpeg2, avc, bd, hd dvd screen shot comparisons
 

http://www.avsforum.com/avs-vb/showthread.php?t=827529

wouldn't normally link to another forum, since it's pretty bad manners, but this is such an interesting thread that i felt it was worth it. plenty of screen caps, comparisons, and the like.

It's probably the least scientific, most frustrating, and ultimately most pointless thread on AVS. And that's saying something.

sorry you feel that way, but examining the actual product via screencaps is more worthwhile than a slew of "when is ***** coming to x format" posts, or "x format is dead because...". infact i can't think of any more useful threads outside of the insider thread, and the release thread.

I can't think of a worse way to compare HD quality than screen caps. Seeing it in motion is the only way to judge.

Exactly. And besides, it's not like we ever have these comparisons handy when we're actually watching the movies.

say what?! you can't think of a worse way to judge hd quality than by actually looking at the individual frames?! i can think of a worse way: seeing it played back at normal speed. the issues are far more noticable by studying the individual frames, where there's actually time to examine what is happening.

If it can't be spotted except by freeze-framing and zooming in however many hundreds of percent, is it really an issue?

I don't know about you, but I don't watch my movies by pausing them and then advancing the frames, one at a time.

I absolutely agree. What a person is likely to see during normal speed playback is completely subject to their delivery system and any artifacts, defects or eccentricities it may introduce. To say nothing of the fact that most people simply do not have the ability to accurately detect such things in the first place.

In a close race, when it's necessary to determine the winner by "photo finish", a competent judge would hardly choose to rewatch footage over and over again; it is necessary for them to look at still images.

Would they look at still images taken with different equipment and then try to determine which still image is the most accurate? Do they take still images from different races and try to determine which is the better horse?

I'll admit that it's not a perfect analogy, but I think it deserves a lot more credit than you seem to be giving. Of course I would not advocate making an apples to oranges comparrison between two different films. If the debate is regarding particular compression codecs, and the problems or benefits of each, then the best, most revealing comparrison would be had from comparing specific images from the same film, after it had been compressed with each of the given codecs. The point that needs to be made is that a viewer can see specific things in a still frame which they can't see when the image appears to be in motion.

What about film restoration? Would a technician be better off examining the condition of a film while it's playing out at 24 frames per second, or could they get a better feel for the print quality by examining each frame individually? Obviously, with a damaged print, defects are going to be visible during playback. However, in order to more accurately assess and later repair the damage, the individual frames will by necessity have to be examined individually.

I'm just saying that trying to draw conclusions from potentially faulty examples (since so much owes to different inputs, there's the possibility of drawing a faulty conclusion from an unrepresentative sample, etc.) is a bad idea.

There's such a "my codec is better than yours!" mentality on a lot of these forums that I think people are going to try to draw something definitive. These sorts of examples are useful to demonstrate potential issues, but it shouldn't be taken as anything more than that.

I agree that many of the arguments here and elsewhere are completely unnecessary and, frankly, destructive. Regarding the various codecs, I do think it's fair to compare them, although, ultimately, I would also assert that most people are no more qualified to accurately judge the differences than I would be to perform open-heart-surgery!

this isn't about watching the movies, but about assessing the way in which they have been encoded. i'm assuming you don't test all of the chicken that you consume, and yet chickens are certainly tested for infection. there are certainly plenty who proclaim such-and-such codec as the only one they want to watch films in. well, here's a chance to see if they are basing that view on tangible evidence or just sheer marketing.

the harder it becomes to spot issues, then the less important they are, yes. but even if there are noticable problems it is still worth slowing the motion to a standstill just to make sure, and to fully appraise the issue. otoh there are clear differences to be seen in the frames posted to this particular avs thread. if further comparisons reveal similar patterns then it may be possible to generalise about the effects of the various codecs.

Even so, all you're really judging is the skill of the person who did the encoding, not necessarily the codec itself. Every video compression codec is prone to artifacting if handled poorly, and capable of superb results if handled well. The quality of the compression work itself is more important than the codec or bit rate used.

:up: Exactly.

Exactly. Sony's non-Superbit titles are a perfect example of what transfers can look like if not enough attention is paid to the encoding process.

the most important aspect of any image is the master it was taken from, which is why the mi-iii frames are so interesting: it seems highly likely they are from the same master. as to the skill of the encoder being more important than the quality of the codec, i find that to be a convenient excuse for not looking at differences between codecs. on the other hand i'm glad that none of the people who proclaimed a particular codec as better are posting in this thread about how impossible it is to make such a judgement.

It's not convenient -- it's the way it is.

With a good cross-section of material captured in a consistent way, that can be telling, but just snapping one shot of MI:III and saying "look! MPEG-2 is teh winner!" like that guy on AVS is doing is not.

and yet i can't remember similar issues being raised when various members of this forum proclaimed their preference for a particular codec...

Well, at the time, when you have virtually nothing but lackluster MPEG-2 releases on Blu-ray and virtually nothing but sterling VC-1 releases on HD DVD, that is as representative a sample as was available at the time. I was more in the "doesn't sound like BD-25 is enough for MPEG-2" camp than "VC-1 is the winner!!!!!!!!!!!", even though some subsequent releases proved that assumption incorrect.

I can't imagine what you want me to say. I'm saying no codec is a magic bullet, so what are you criticizing, exactly? That statement inherently takes me out of the "VC-1 is God!" camp, it applies as equally to Blu-ray as it does to HD DVD, and I've written positive reviews of almost every AVC title I've been sent, for what it's worth.

Tell me where the logical hole is in my argument.

That is saying a lot. Pretty pointless!

format to format, but not codec to codec. there existed, and still exist, many fine mpeg2 encodes on dvhs - alien being the example that springs most readily to mind.

btw i'm not sure exactly why you think my comment applies to you. as far as i can tell you haven't proclaimed frame to frame comparisons worthless simply because you don't like the early results. a small sample is indicitve only of itself, but it could in time start to show trends, and it would be foolish to dismiss it out of hand. it's dissapointing that other members have taken this attitude. presumably they don't read reviews on this site, or if they do they must ignore the video and audio ratings.