-
720P or 1080P at 100MBit
When the HVX200 is shooting 1080, it is always 100mbit. Is there any other frame rate besides 720 60p when the camera shoots 100mbit? What I’m wondering, is if you took 720 30p footage at 100mbit (assuming that that is possible) and then compared it to 1080 at 30p, which would look better? Is it better to have a smaller picture and less compression, or a large picture and more compression?
-
12 Replies
-
DVCpro 50 = 6.8 MB/s
DVCpro 720p = 6.8 MB/s
DVCpro 1080 = 13.7 MB/s -
That doesn’t quite sound correct- where do you get those numbers?
-
[Steve Freebairn] “What I’m wondering, is if you took 720 30p footage at 100mbit (assuming that that is possible) and then compared it to 1080 at 30p, which would look better?”
It doesn’t work that way. With DVCPRO-HD, each frame takes up exactly the same amount of bandwidth. Shoot more frames per second, it takes more storage space. Shoot fewer frames, it takes up less storage space. But in each case, the frames are compressed exactly the same. So 720/60p = 100 megabits, 720/30p = 50 megabits, 720/15p = 25 megabits, etc.
Now, with your question regarding bigger frame/more compressed vs. smaller frame/less compressed, there is a way to evaluate that; DVCPRO50 is 50 megabits of bandwidth with very mild compression. The frame size is half the size of DVCPRO-HD 720p(720×480 vs. 720×960) and the compression ratio is half as well (3.3:1 vs. 6.7:1). But that’s standard-def; I think you were more interested in sticking with high-def.
—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available at https://www.dvxuser.com/articles/dvxbook/ and at Amazon (https://www.fiftv.com/db) -
Basically to clarify my question after thinking about it more, here goes. If space isn’t an issue, what is the best resolution to shoot 24 or 30 p footage? 720 or 1080? From the previous responses I would think that 1080P would be superior to 720P. Is that correct? Obviously if you shoot 1080, you lose the ability to overcrank at 60, but couldn’t you just switch down to 720P for that? How well do 720 and 1080 mix visually?
-
I think 1080p24 should work out looking better than 720p24, but at the moment, that’s just a guess until we get the camera to play with.
For slowmo shots, you could shoot either 1080i60 or 720p60. I don’t know which would work better, but it will be interesting to see…….
Graeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
-
[Steve Freebairn] “If space isn’t an issue, what is the best resolution to shoot 24 or 30 p footage? 720 or 1080? From the previous responses I would think that 1080P would be superior to 720P. Is that correct?”
At the same framerate, 1080p will always be better than 720p, as you’re getting twice as many pixels per frame. So 1080/24p is going to have twice as many pixels as 720/24p. It will also take up twice as much space, but you already said “if space isn’t an issue”. So yes, 1080/24p should be superior to 720/24p in most circumstances.
If you plan on doing a lot of off-speed variable-frame-rate shooting, you may want to stick with 720 for the whole program. Or, if you’re planning on delivering your final product in 720p, you may want to stick with 720p for origination. Otherwise, I’d expect 1080p should be the preferred mode for those shooting 24p.
—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available at https://www.dvxuser.com/articles/dvxbook/ and at Amazon (https://www.fiftv.com/db) -
Thank you everyone for your responses
-
[Barry Green] At the same framerate, 1080p will always be better than 720p, as you’re getting twice as many pixels per frame. So 1080/24p is going to have twice as many pixels as 720/24p. “
Seeing as the details on the CCD block have yet to be released and we don’t yet know how exactly the HVX is going to achieve it’s 1080P footage (I think it’s safe to assume it will not have 1080 chips) isn’t it possible that 720P footage may actually be cleaner than the 1080 footage?
I’m not trying to complicate the issue, but if you consider that the footage is going to be compressed into the same datarate (when duplicate frames are removed both 1080 and 720 should be around 40Mb/s, right?) then isn’t it possible that we will see more compression artifacts in 1080 than we will in 720, due to it’s having to compress twice the pixels per frame in 1080?
I may be wrong on this, and if so I hope that Barry or someone else will correct me.
But I just wanted to point out that resolution isn’t everything when judging formats. -
I just realized the error of my ways.
Ignore my last post…as I’m wrong.1080 is a 30fps format, while 720 is a 60fps format.
So the datarates at 24fps would differ quite a bit. -
1080p has twice the data rate per frame as 720p, but it also has twice as many pixels to compress, so you’d expect the quality to be around the same, but, you could always scale the 1080p down to 720p and get a better looking 720p….
Also, I think there’d be less detail per macroblock in 1080p so it might end up being more efficient.
Graeme
– http://www.nattress.com – Film Effects and Standards Conversion for FCP
Reply to this Discussion! Login or Sign Up