What does 60p footage look like?
 

My understanding is that 60p has a smooth, interlaced look. If so, is there any advantage of 60p as opposed to 60i as far as the way it looks? Does it look like video or film (so to speak)? Moreover, what difference would I notice in footage that is true 60p (as in the JVC JD200) compared to 60p over 60i footage (as in the Panny HPX170)?

In my particular case, that if I shoot in 720 60p instead 30p, camera changes HD to SD.

I have a JVC GY HD110

Cheers Bill.

The "P" specifically says it is not interlaced. played back at 60fps speed, it'll give a more lifelike image. More often, it's used to do 50% slowmo. Played back at 30P, every 1/60th sec frame occupies 1/30 of a second. So every 1 second of footage you shot is stretched out seamlessly to 2 seconds.

I completely understand the differences from a technical standpoint. I'm asking what they look like to the naked eye.

Bill, 60P doesn't look EXACTLY like 60i. It looks a little like shooting with a SLIGHTLY increased shutter speed, introducing less motion blur and thereby creating a SLIGHT strobing effect. I find it beautiful but it's not the same as 60i so it's still a "look".

If you've seen SD at 60i shot with a 1/125 or 1/250 shutter, it looks SOMETHING like that.

Thank Mr. Eric G. for these! Made my decision for me last year.

http://www.dvinfo.net/conf/jvc-gy-hd...lls-video.html

Shaun, thanks for the info. I have a clearer idea now. Does the 60p setting use a shutter speed of 60 by default? If you lowered it to 30, would it become more strobe-y (sort of like when you shoot with a ss of 30 in 60i)?

Check the link I posted whilst you were formulating your response. 60P by default uses 1/60 shutter.

Thanks for those terrific clips. I note that 60p footage is noticeably darker than the 30p stuff at the same shutter speeds. Is this normal?

It also appears to me that the 60p/30ss clip looks like it has better resolution in the trees than the 60p/60ss clip. Huh?

What it looks like depends A LOT on what you are watching it on ....

60P and 60i with 1/60th shutter will have the same temporal motion so will look the same depending on what you watch it on. 60P on a flat panel ( LCD or Plasma at 60hz refresh) will look very similar to 60i on a CRT viewed at or beyond the recommended viewing distance( outside the distance where scan lines can be seen to let the CRT phosphor and eye/brain work ) They won't look the same on the LCD or Plasma because the 60i will have to be de-interlaced and the de-interlacing method will determine what is seen more than the difference between 60p and 60i!!!! The temporal motion will be the same ( motion blur is the same because the shutter is the same 1/60 shutter but the de-interlacing will potentially introduce loss of vertical resolution and other artifacts which will not be present in the 60p image( as long as they both started out the same vertical and horizontal resolution). In a lot of the current batch of new camcorders the sensor block and DSP are already 60p at source and just record what is selected by the user and to the selected media. In other words the electronics can either record the whole frame bit map every 1/60 sec or selectively odd or even fields from each 1/60 sec progressive frame for the interlace recording. I think Sanyo VPC-FH1 and VPC-HD2000 are the only consumer cams that record full HD 1920x1080 at 60p. Some of the Panasonic camera record 1280x720P60 as well as 1440x180i or 1920x1080i.



Ron Evans

I respectfully disagree. 60P and 60i do not look the same but have similarities.

60i looks real. 60P looks "hyper" real.

>> 60i looks real. 60P looks "hyper" real.

On what? As Ron points out, the end result is largely determined by the display technology you choose to view on.

When it comes to compression, 720p60 is much better when it comes to high-motion compensation.

on a static 60i image, if each field is displayed linearly, still images will flicker and high resolution sources will also flicker. 60p never flickers so it's much better for slow-motion and static images.

You are entitled to your opinion but the HD sports networks look pretty real to me.

Ron Evans

Hey guys, i need an english tech lesson:what's the strobe effect?

thx

I think they are referring to the strobe effect as a slower framerate in which you can see the frames changing.

Look at a faster pan while recording 24p and you will see the motion going faster than the frames, which shows the frames changing.

Slower shutter speeds would make the image mushy, not stroby imho.

Faster shutter speeds might look more stroby. Sort of slices of images rather than s smooth flow between frames.

60P has twice as much vertical information in a given 1/60th interval over 60i. 60i also swaps between upper and lower so not only are you losing resolution in comparison, you are losing temporal resolution (have the temporal resolution on every line)

This does make a difference on certain subject matters.

Now, 720p60 may not appear to some as good as 1080i50 because of the decreased (although ultimately similiar) spatial resolution, but comparing apples with apples - i.e 720i60 (not a real format) to 720p60 or 1080i60 to 1080p60 (a very uncommon format because of the bandwidth required), the interlaced ones are literally half an apple, compared to progressive which are whole apples.

Of course, this is assuming a chain in which footage is shot at the same frame rate as display, and no film mimicking cadence etc is required, and appropriate shutter speeds etc are used.

Ultimately, the faster the refresh rate, and the higher the resolution, the more 'window' like an image is going to become in terms of perceivable spatial and temporal qualities. Your brain will not notice how the image is being displayed, and only be able to see the image being produced (and any intervening materials like glass etc.)

I'll just stir the pot up a bit and cackle... (too late for Halloween I guess) but from a quality camera system or 35mm film I have NEVER seen 1080i (60i)broadcast look as good as a 720p 60fps broadcast. Why HBO broadcasts in 1080i is beyond me. Nothing more lame than watching Soprano's HD interlaced and watching the HDTV struggle to to deinterlace the super compressed signal. My 720p TV shows and movies look better from iTunes than HBO HD ond DirecTV of the same or similar programs.

However:

I have heard good things about DirecTV's VOD 1080p (24fps only), though my box died and I haven't bothered to call in a replacement so I can't say first hand.

As I posted earlier it depends on the display your watching the program on. All flat panel ( plasma and LCD) have to deinterlace an interlaced video to display on the progressive screen ( 60hz at least in NA). How this is done has more effect on the video than most else!!! IF the video is 1080i and the LCD is a 720p set the display has to deinterlace AND scale the image. A 720P incoming signal will look way better than a 1080i on a low cost 720p set. Another reason for the high advertising dollar sports networks to use 720p !!! The video is a lot better on most sets. Fits nicely on the 720p low cost LCD's and 60p makes the scaling easier for the 1080 sets.
The ideal for me would be 1920x1080P60 but that isn't in any of the standards!!!
The newer 240HZ sets like my Sony do a good job of both a 1080i input and 720p since they interpolate extra frames and smooth out any input ( including 24p!!!!)

Ron Evans

I agree Ron.

I am surprised at the difference just between Plasma & LCD.

I have a 1080p plasma and my dad just picked up a 1080p LCD. We both have DirecTv.

The LCD really handles the images in a different way. In a way, almost everything looks interlaced. A real "video" feel.

My plasma makes everything look filmic. I much prefer the plasma.

When I see Blu-rays playing in a retail store on one of the new LCD tvs I am shocked at how interlaced the 24p content looks. They are doing something with adding frames at the television stage as that stuff does not look that way in the theatre.

This stuff is so complicated...

I have Panasonic 1080p Plasma and a new Sony 240hz LCD. Since I do not like the slow frame rate look I like the Sony for a lot of things better than the plasma. The Sony interpolates the signal to create a refresh frame rate of 240. That's why it looks so smooth but can playback 24p as one would expect in the cinema. A frame rate of 24 with flicker rate of a 5 blade projector shutter.
A guess my goal is different to lots of people. I want the set to look like a window on the event. If its a concert I want the feel of sitting in the seat in the audience. When I am in a concert and move my head the background doesn't judder!!!!! etc etc
Remember 24p was an economic compromise. Nothing to do with technology or art. It was the best the business community could deliver to meet their business case. The technology and the art was developed to make the best of the choice. Film camera technique was developed to mask the deficiencies of the frame rate( the rate was more to deliver acceptable sound).
I don't use my film camera anymore( thought it was the greatest in the 60s) can't wait to get HD with high progressive frame rate .

Ron Evans

Good points.

I am not a massive 24p fan, but I do think it adds a certain unique distance and time suspension feel to footage.

For example, I shot a concert using 720p60 and when I put the 60p footage on a 24p timeline, the scene had a uniqueness like the event was captured in the past.

It lost that present feeling of 60p, but added a different, interesting point of view.

It all has a place. The problem is trying to find out if your clients want (or really don't dislike) a certain look before you shoot their project.

I agree for a fictional story do whatever it takes to get the emotion into the video. The problem I have is just because 24p works for a film doesn't mean the news would look that good in 24p!!! It was OK when there was no choice. I for one like to see anything that is intended to place the viewer "there" be as close as possible to reality. High resolution and frame rate, a window. To me a record of an event falls in this category. A story about events is different. I think this is where I have most of my issues with some HD material on TV. There are supposed documentaries shot like music videos!!!! Very annoying.
A story is different, use whatever effects work. The viewer either likes it or not.
Most of my interests are in archiving performances hence my desire for high resolution and frame rate. I do not want to second guess the director, lighting designer, choreographer etc etc..

Ron Evans

1080p60 will be great if it ever happens, but a lot has to change to be able to distribute in that format.

I am not so bothered about delivering in 1080P60 just acquisition as it would make all the other conversions a lot better I think. No interlace artifacts and down conversion may also be improved.

Ron Evans

Good point. Keeping the 60Hz standard for DVD is the best way.

I think I heard the major networks shoot the NFL etc... in 1080p60

Might be wrong though.