Very good HVX vs HD100 article
- Thread starter stevenblatter
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An "I frame" is a compressed frame which is complete in itself, comparable to (say) a JPEG in still photography. Obviously if you have 25 of these every second, that's effectively video (I frame only), and DV, DVCProHD are both examples of this sort of codec. Every frame exists in it's own right.Mirezzi said:
Since generally there is a large amount of similarity between successive frames, other coding systems take advantage of this for the sake of efficiency, and only transmit a limited number of complete frames, the rest being represented by the DIFFERENCES between these I frames. This results in a large saving in data, and if not overdone, (!) no decrease in relative quality.
The main disadvantage is that it is inherently more complicated, and requires more power to process. Worse, it cannot be so easily edited, since there must be an element of reconstruction of frames to edit, then a reforming of a different MPEG stream. In practice, it can be done, as many people will testify, but it's not as easy as an I frame only system.
The "cost" I referred to is that with an I frame only system, then whilst inherently simpler, it is also going to be a higher bitrate than such as an MPEG2 system. Hence, for HD, it can't use an inexpensive tape drive (limited to 25Mbs) like HDV does, and will fill up a solid state memory card 4x faster than an HDV stream would.
Gotcha, thank you very much, so DVCPro HD footage takes up much more hard drive space but is ultimately easier for processors and editors to work with? Conversely, while it's demanding on a processor, HDV footage takes up no more room than DV footage?
Also, can somebody/anybody explain what all this 4:2:2 versus 4:2:0 talk refers to? God I love this place.
Also, can somebody/anybody explain what all this 4:2:2 versus 4:2:0 talk refers to? God I love this place.
Very limited testing, to the extent I think I've really said it all, and to the extent that the only firm comment I feel like making is that (in terms of picture quality) both these cameras gave what to us was a very nice picture, to the extent that which was the better just would not have been the most significant factor in deciding between them.brianluce said:
Far more relevant would be the HD100 only doing 720p/25 for HD (not 50) going against it, but in it's favour having those superb ergonomics. (PLEASE take note of that, Panasonic.) Many other relevant differences between them, all far more significant than 'quality' in our view, and admittedly unscientific limited testing.
Regarding 1080v720, then I feel that the difference only really becomes significant with an input quality that 1/3" chips can't produce. With a top 2/3" camera, I suspect the format (720/1080) would be the limiting factor, in this case I suspect the main limiting factor is the lens and camera front end. This shouldn't be seen as denigrating these cameras, they are very good, but there is better.
More or less, though some solutions "expand" the HDV on ingest for editing (to make the editing easier).Mirezzi said:
Ratio of chroma pixels to luminance. For 4:2:2, there are only two U, two V pixels for every 4 luminance horizontally, but an equal number of U,V, and luminance vertically. For 4:2:0, it's the same horizontally, but only two U,V vertically for every four luminance.
To further complicate matters, the reference ("4") varies, representing 1280 for HDV but 960 for DVCProHD. Consequently HDV has potentially 33% higher luminance and chrominance resolution horizontally, but 50% lower chrominance resolution vertically. I say potentially, as this assumes the camera front end can fully exploit it.
Don't get too obsessed by it, there is a lot more to it than simple headline numbers.
toke lahti
Well-known member
Another thing about the article:
did you people see the motion blur pictures of Hd100?
All of them seemed to consist of two frames? Or even fields?
Is Hd100 really an interlaced camera or does this fancy "motion smoothing" blend frames even when its off?
did you people see the motion blur pictures of Hd100?
All of them seemed to consist of two frames? Or even fields?
Is Hd100 really an interlaced camera or does this fancy "motion smoothing" blend frames even when its off?
harddrive said:
Phew, because I understood just about none of that.
One more rather idle question...what is everybody using to look at this .m2tx file extension? I downloaded some clips Barry posted of the HD100 and opened them up in VLC which worked fine but the framerate is really choppy. Maybe Barry just stripped some frames out to save on server space...or am I using a bad application to view this stuff?
The Sarlacc
Well-known member
Mirezzi said:
WMV SUCKS!!!
I'm sure I'll get flamed for saying it, but its such a horrendous format. Or perhaps its better to say that players for WMV are terrible...either way can't stand seeing anything that ends wtih .wmv
My understanding is that whilst this camera can only record 720p/25 to tape, it outputs 720p/50 (which is what a monitor etc will expect). With motion smoothing "OFF" every frame is simply repeated, but when set "ON" my understanding is that the alternate frames are a mix of the two real frames either side.toke lahti said:
What I'm not sure of is what gets recorded to tape. I heard one theory that HDV1 *IS* 720p/50 (60 in US) and the motion smoothing is done before recording. The other possibility is that 720p/25 is recorded, and motion smoothing done on replay.
Re-reading the article, it does seem that an effect he puts down to HDV coding is nothing of the sort, but rather the motion smoothing (blending two frames) feature of the HD100.
The Sarlacc
Well-known member
brianluce said:
lol...well then I guess your SOL on that one. You'd have to go the best you can off of footage people are uploading to this site I suppose.
The Sarlacc said:
It's not easy my friend, and that's why i disagree with those who dismiss forums like this as nerd lounges populated by pixel counters. People like me, living on the edge of the galaxy, sift through these forums obssessively because we CAN'T get ahold of of demo or rental units.
You guys in LA don't know how good you got it.
The Sarlacc
Well-known member
brianluce said:
Oh I know how good I've got it
If you're looking at a serious investment of 10g into a camera, then perhaps the cost of a plane ticket isnt so much add in to the price?
Barry_Green
Moderator
I wouldn't support that, no. I believe 1080 is superior, in all the testing I've done with it I have yet to find a circumstance where 720 delivers the better picture.brianluce said:
But 720 has compelling features: 2.5 times as much recording time, and variable frame rates, lead most people shooting on the smaller cards to choose 720. And the amount of resolved detail isn't THAT much different; 1080 holds a maybe 15%-20% edge in terms of resolved detail. Is that worth giving up VFR and 2.5x longer card recording? For some jobs, no. But when I have the recording space available, I'll choose 1080 every time.
Nothing wrong with 720, 720's high def just like 1080 is. But 1080 just retains a bit more detail, and makes for even better 720 than the native 720 mode does.
Barry_Green
Moderator
Best way to test would be to turn edge enhancement OFF. On the JVC you can do that -- you can set it to all the way off.brianluce said:
And then you're left with nothing but the actual resolution. No edge enhancement at all. Just the raw resolution.
Try it. You may be surprised.
Can't absolutely get there with the HVX; I believe -7 is close to off, but not necessarily all the way off. But very close.
So HVX at -7 vs. JVC at "OFF" is probably the one test that will show the resolving capability, without edge enhancement as a factor.
Really wouldn't like to say, and the whole point is that I didn't really find it important. There ARE differences between the cameras, some big ones, but quality differences just weren't significant enough, or even one way enough to vastly influence any choice one way or the other. Which is why I thought the article in question (by and large) got it pretty right. He had time to do more comparative testing, our look was more of a ballpark evaluation, and more important in many ways for what it DIDN'T show than what it did. No vast differences between them (quality wise). No 'falling over' of the HDV codec on movement, certainly not in the way a colleague had been led to expect.brianluce said:
Choice of camera (IMHO) should far more be based on factors such as P2, variable frame rates, and usability of the camera. We found reasons which would make us go with the HVX, and reasons not to (handheld ergonomics mainly), and other factors which would sway depending on what you were doing. But if sheer picture quality is really the be all and end all, then one really needs to think long and hard about a camera with a bigger than 1/3" sensor. and not obsess too much about relatively small differences between the 1/3" crop, even if it means hiring. That's why developments such as Red are so potentially interesting to indie filmmakers, and Infinity to people in the broadcast world. 2/3" quality at a price differential much lower than previously the case.
LearningVideo
Well-known member
brianluce said:
Barry disagreed. Read his post about this.
brianluce said:
Show us what article tested HVX 1080 24P -7 for HVX against 720 24P OFF for JVC. Besides, We are talking about THIS article.
brianluce said:
No sarcasm on my part whatsoever. No bias whatsoever. I am the first to admit that Z1U has better low light, low noise than HVX.
brianluce said:
Exactly.
brianluce said:
You are completely missing the point here. We are discussing a particuar article that for either clear bias, or clear ignorance of the cameras ignored to perform the REAL TEST that compares HVX with HD100.
This is why Jan was concerned. No where in my posts I suggested that HVX is better than JVC. All I suggested is that since the original article purpose to compare the two cameras: Why not compare HVX 1080 24P given that this is the best image it produces?
Is it fair? I have my reservation
I would fully understand why you, as an owner of HD100, would want to support the findings of this article regardless of their merit. When I buy a tool, I really would want it to be the best purchase possible against all competitors, and maybe it is. However, I would not go the route of denying my competitor the chance to produce the best image in order to win hypothetical editorial contest.
Barry_Green said:
1080 IS superior, not by a massive amount, but if I had to shoot something for cinema theatres I'd go with 1080p because even a small amount of extra detail goes a long way on the big screen. If you want variable frame rates, shoot 720pn and uprez it to 1080p then add it to the project. Because the difference is not huge I'd hazard a guess it'd fit in nicely, but for all the other footage shoot 1080.