HF100 clip - pl sidentify

[intracube]

Actaully I cannot upload any of the worst clips because it features a lot of people and I dont want to vilate their privacy. However, the juddering/strobing effect is so bad that the video is unwatchable. THis cannot be right.

Is it possible you had the camera set to aperture priority for some of the recordings?

If you were shooting in daylight, the camera would then have adjusted the shutter speed to maintain exposure. Bright daylight, coupled with aperture priority and the lens aperture being manually set wide open might mean the camera uses 1/1000sec shutter, for example.

This would mean virtually no motion blur. Motion blur helps soften the edges of anything moving and is very important in reducing judder when filming at low frame-rates. As is shallow depth of field, and steady camera movement.

Find a problematic clip with movement, go through it a frame at a time and see how much motion blur is there.

[akkers]

Here are 2 test clips I shoy today (ok, a lot of movement for exaggeration):

00122.MTS
00123.MTS

I converted these into mpeg interlaced tff using tmpgc:

00122-3.mpg

[jagabo]

All normal 25p frames, encoded 25i TFF.

What that means is that each frame of video contains two fields from the same point in time. So you have 25 different pictures every second.

When a frame is encoded progressive it is compressed as a single image. When a frame is encoded interlaced the encoder assumes each field is a separate image. The two fields are separated and encoded as individual images (at least figuratively). On decoding the two images are decompressed then woven back into a frame.

[akkers]

The scripts mentioned higher in the thread - do they produce interlaced or progressive footage? How would you interepret that?

I have tried both variations and I am getting encouraging results with some small clips. Motion is sufficiently smooth to be watachable although there is some loss of sharpness. One thing that shows up is that sudden-sharp movement does'nt translate well - it appears to miss frames. But the resulting footage is much more watachable than the garbage out of the cam that I was working with.

[edDV]

Have you tried shooting 50i ? That will be twice as smooth.

If it must be progressive, you can junk that camcorder, get a Panasonic TM/SD 900 and shoot 50p.

If you are after that 24p/25p "film look", you need to up your game with a better camera and narrow depth of field lens. Check this real world account.
http://www.luminous-landscape.com/techniques/3_years_later_dslr_video_one_mans_perspective.shtml

[akkers]

Yes, I agree. I have always shot in 25/50i and had no problem. On this occassion the settings must have got set to 25p by mistake.

[jagabo]

The scripts mentioned higher in the thread - do they produce interlaced or progressive footage?

The output of those scripts is progressive. DoubleFPS2() converts 25p to 50p. Between each frame of the original video a frame is synthesized with in-between motion. So the output has twice as many frames as the input.

But motion interpolation techniques like that do not produce perfect results. Complex motions can get them confused. For example:

[intracube]

Here are 2 test clips I shoy today (ok, a lot of movement for exaggeration):


[Attachment 10277 - Click to enlarge]

[Attachment 10278 - Click to enlarge]

The shutter in these clips matches the framerate:
Each frame = 1/25sec and the shutter is also 1/25sec
Comparing neighbouring frames, there's no gap in the motion blur.

The shutter speed on the other clip you posted was twice as fast, so there's less motion blur and gaps in the movement. It looks like the Cine mode doesn't use a fixed shutter. I've just confirmed similar behaviour with my HFS21 (I've not used Cinemode before), and there's a thread discussing the issue with another Canon cam - the HV20, here.

It's possible the camera might increase the shutter speed even more under bright light - to 1/120 for example. Coupled with a hand-held recording and low frame rate, this would cause a lot of judder.

I almost always shoot Shutter Priority.

As has been said, unless you want to shoot 25p for a specific effect; shoot 50i AND use Shutter Priority with the shutter set to 1/50. I don't know of an easy way to reduce the judder of the footage you've already shot other than using motion interpolation.

[akkers]

Just to summarise and report back. I usually always shooto 25/50i on the HF100 but in this occassion I had set the 25p by accident. The footage looked ok on pc but on a PAL tv looked juddery (motion was very very juddery/jittery). But worse still the whole picture was unstable and had a strobe like effect. Watching for 2 mins gave me eye strain. This was the case when played on a CRT/LCD or HD LED tv (even in 25p). Playing the footage straight from the HF100 through a HDMI cable on HD tv also gave same results. It was the unstability and strobe effect of the pic that made it unusable.

Taking on board sugestions above, I tried some scripts. Interframe appeared to do the job but was slightly slow. I tried the script provided by jagabo which seemed to produce similar results and performed better through frameserve. So used jagabo's script to convert all the footage. The result is not brilliant but its reasonable and watcheable. More importantly the footage is 'rescued'.

I am not entirely sure why Canon has shipped out such a setting which produces unusable footage. I'd like to know about this subject and the whole thing about the 25p when it is being pushed as the future of tv. Where is the future when 25p cannot properly capture normal motion? Camcorders are supposed to capture motion; if I wanted to capture still life, I would use a DSLR photo cam.

[jagabo]

in this occassion I had set the 25p by accident. The footage looked ok on pc but on a PAL tv looked juddery (motion was very very juddery/jittery).

The video should have looked about the same on a PC monitor and a TV (though, the bigger the picture, the more noticeable the jerkiness is). Are you sure your TV (or player) isn't screwing up? Have you tried playing the video on other TVs or with other players?

[akkers]

No they did'nt play the same on everything. On the pc the original footage looked pretty smooth. However, playing it ona PAL tv produced awful results with juddering and strobing, on crt/LCD/LED tv. I was playing through a USB drive and then I even cut a dvd and playd that through the dvd player with the same results. I even tried playing on a 14" CRT tv. Even the opriginal HF100 camcorder cant play the footage correctly.

What has disturbed me most is the strobing effect which made the pic very unstable and unwatachable.

Incidently the original footage was shot in summer on a sunny day. So it is possibel that the shutter speed may have shot up as I am used to shooting in aperture mode (hand-up from my dslr activities.

[poisondeathray]

I am not entirely sure why Canon has shipped out such a setting which produces unusable footage. I'd like to know about this subject and the whole thing about the 25p when it is being pushed as the future of tv. Where is the future when 25p cannot properly capture normal motion? Camcorders are supposed to capture motion; if I wanted to capture still life, I would use a DSLR photo cam.

25p is usuable , but you have to use different shooting technique

Have you seen any BBC movies or productions? Dr. Who ? 25p is and will be the future for many years in PAL areas

I notice many of your examples are weddings. I don't know about the UK, but many "high end" or expensive weddings packages are shot in 24p in North America for the filmic look with shallow DoF. Many brides want to look like movie stars, and they want their wedding to look like a professional movie, not a family vacation video. I suspect it's the same in the UK, but with 25p. They charge a lot more because their setups are more expensive and it's harder to shoot properly than run & gun handheld style

[_Al_]

For 25p mode you have to set shutter manually to 1/25 or 1/50 (that might introduce judder already).
Longer time to capture a frame, there is less room for judder.
It will introduce blurry image , so there are rules, no panning , camera should be still, or you follow object, where object is in focus and background is blurred.
Other "byproduct" of longer shutter is too much light on the sensor while outside, F-stop is automaticaly set to F8 and higher with shutter priority set to 1/25, no good for image, so you have to use ND filter.

So your camera is not bad, that's how it works for lower frame rates.

To shoot 25p with automatic mode is recipe for judder, outside while sunny without ND filter can shutter go to 1/100 or shorter 1/200, doesn't matter what camera. If you shoot 50i there is 50 information about movement per second, so even if you have 1/200 shutter, it is not that bad as you'd have 25p footage. Where there is only 25 informations about movent and our eyes notice that, it looks more artificial, annoying, judder is introduced .

[akkers]

(1) So why is 25p being touted as the future when it has so many problems and restrictions?

(2) If 25p footage plays ok on my computer screen then why cant it play correctly in 25p on a 1080p LED TV? Surely the HD TV can play 25p footage properly even if interlaced fotage is doomed.

[jagabo]

(1) So why is 25p being touted as the future when it has so many problems and restrictions?

50p and 60p are the future. 25p and 30p are good for people posting online.

(2) If 25p footage plays ok on my computer screen then why cant it play correctly in 25p on a 1080p LED TV? Surely the HD TV can play 25p footage properly even if interlaced fotage is doomed.

TVs can display 25p and 30p as well as computer monitors. If your TV isn't then there's something wrong. Though, as noted earlier, bigger and brighter exacerbates the problem.

[edDV]

(1) So why is 25p being touted as the future when it has so many problems and restrictions?

Consider 25p (or 23.976/24p) a pro format. You need a pro workflow from camera/lens to camera support to editing/encoding.

Most learn the art in trade apprenticeship or film school.