Camera for progressive video

[Martin Chambers]

I am producing short clips for internet use and I currently have a Sony FX1 camera.
However, interlacing is a problem since all computer displays are progressive scan.
Would I be better off with a camera that shoots in true progessive mode and if so, which is the best one?
Martin

[Soopafresh]

I like the footage I've seen from the Canon HV20

http://447productions.com/HV20_Test_TEM.mov

[Martin Chambers]

It's not sophisticated enough for me.

[Richard_G]

I'm surprised the FX1 can't do it, my VX2000E can. Do you actually need HD, or would a VX series do the job?

[edDV]

The dumb ass solution is to shoot 1440x1080i/29.97 (59.94 fields per sec) and delete even fields for 1440x540p/29.97 then downsize from there.

For web video what is the problem with that?


Oops, PAL would be:

... shoot 1440x1080i/25 (50 fields per sec) and delete even fields for 1440x540p/25 then downsize from there.

[BJ_M]

the BEST would be a Sony F23 or a Sony HDC-F950

[Martin Chambers]

The dumb ass solution is to shoot 1440x1080i/29.97 (59.94 fields per sec) and delete even fields for 1440x540p/29.97 then downsize from there.

For web video what is the problem with that?


Oops, PAL would be:

... shoot 1440x1080i/25 (50 fields per sec) and delete even fields for 1440x540p/25 then downsize from there.

I suppose that's an obvious way of doing things - one that I hadn't thought of!
What's the best way to delete the even fields?
I use Premiere (Elements) for editing. I wonder if the deinterlace option discards them?
Is there another better tool that you would suggest?
Martin

[Martin Chambers]

the BEST would be a Sony F23 or a Sony HDC-F950

I suppose I omitted to say 'affordable'!

[Alex_ander]

Not a sophisticated solution, but you could use a Sony photo camera for short clips, most models produce 640x480 MPEG1 (=progressive), 25 or 30fps selectable.

[Alex_ander]

... to delete the even fields?

VDub/video/filters/add filter/deinterlace/deinterlace mode/discard field 1

[edDV]

... to delete the even fields?

VDub/video/filters/add filter/deinterlace/deinterlace mode/discard field 1

To get 1440x1080i/50 HDV out of Premiere Elements to prep for Virtualdub, export as 1440x1080i/50 uncompressed avi (codec = none). I don't have Elements so I can't get more specific on menus. Then follow Alex_ander's instruction. Virtualdub can also be used to resize the progressive frames to whatever end size you want.


A quick and dirty alternative is to export from Premiere Elements as uncompressed

1280x720p/25 or
720x576p/25 or
something at the size you want.

Then encode to your export format.

[jagabo]

Discard field deinterlace may lead to moire artifacts.

[Soopafresh]

http://www.dvxuser.com/articles/HVX200/

Progressive, sophisticated, able to leap tall interlacing artifacts in a single bound.

Deinterlacing is almost always a PITA.

If you can get away with bobbing (2X frame rate), the motion artifacts are greatly minimized. You have to reduce the image size to 1/2 to make it look really nice. Compare the smoothness in movement between the bobbed and "normal" deinterlaced clips. You can really notice it in her legs as she walks.

yadif_50fps.avi

yadif_25fps.avi

[edDV]

Guys he wants this to be streamed on the internet.

producing short clips for internet use

He can easily trade 1080i HDV resolution and frame rate. Discard to 25fps will get him there without interpolating new frames. Alternative is to interpolate any arbitrary frame rate and frame size.

If DVD was the goal, the latter is preferred. For what he is doing, why not shed half the fields then downsize?

[Martin Chambers]

Thanks for your help guys, I'm doing my best to follow what you are all saying! I may sound like I don't know what I'm doing, so please go easy with me!
I am trying to produce web video that has no (or precious little) evidence of interlacing.
edDV - The available presets in Premiere Elements are HDV 1080i 25 (Sony 50i), HDV 1080i 30 (Sony 60i) and HDV 720p 30.
So. I shoot in HDV mode and import the footage in to a HDV 1080i 25 (Sony 50i) project, edit and then export in to Virtual Dub where I discard field 1 (or should that be 2?).
I'm then left with an AVI file something close to progressive, is that right?
So if I want to create a flash file or MPEG from there, do I reimport it in to Premiere Elements and if so, as what?
As for the quick and dirty method and the comment about trading 1080i HDV resolution and frame rate, that's a little over my head...
Soopafresh - Are you saying that something as simple as shooting at 50 fps (you call that bobbing) helps? I've looked at the two clips and agree with your thoughts.
In what mode were they shot and what is the significance of the DivX logo on the screen?
Thanks again!
Martin

[jagabo]

Each frame of interlaced video contains two separate half pictures, every other scanline from each, each called a field. VirtualDub's Discard Field 1 and Discard Field 2 will throw away one of the two fields leaving you with a half high image. Either one will work. Both may leave behind jaggy edges or moire artifacts. You should also try Donald Graft's Smart Deinterlace filter.

BOBing is the process of separating the two fields and somehow filling in the missing scanlines to crate full frame from both fields. This will create a 50 frame per second video from a 50 field per second source. VirtualDub cannot do this because it is built on a one-frame-in, one-frame-out model. There are many BOB filter in AVISynth. LeakKernelBob() being one of the best.

A 50 fps video created this way will contain smoother motion but it's twice as much data to transfer and display. Generally not a good idea for streaming video.

[edDV]

It would help if you could better describe the end goal for this video. Web video is generally low resolution and highly compressed to fit the target viewer's internet bandwidth. Typically this is in the range of 300 Kb/s or less with wmv or flash encoding. What are your plans?

A flash encoder will accept interlace or progressive source but most people would deinterlace before sending the video to the encoder. What encoder do you plan to use? What bitrate(s) and frame size?

There should be a way to get HDV source output as uncompressed video from Premiere Elements. This would be in the export settings under export as AVI with codec specified as none.

Give us a little more information on the goals of this project.

[edDV]

Each frame of interlaced video contains two separate half pictures, every other scanline from each, each called a field. VirtualDub's Discard Field 1 and Discard Field 2 will throw away one of the two fields leaving you with a half high image. Either one will work. Both may leave behind jaggy edges or moire artifacts. You should also try Donald Graft's Smart Deinterlace filter.

But remember that anyone out there shooting 720p HDV is also shooting at 29.97 or 25 frame rates not to mention the 24p folks.

Simple field discard from 1440x1080i/25 to 1440x540p/25 results in resolution very similar to 1280x720p/25. If the goal is further downsize there will be no deinterlacing artifacts during motion and jaggies/moire will be filtered out during the downsize. True there will be less motion smoothness but that comes with 30p, 25p and 24p frame rates.

Alternative is to feed the uncompressed 1440x1080i/25 directly to the Flash encoder and let it do the deinterlace, or use Premiere Elements to first convert to 1280x720p/25 or smaller.

[agilpwc]

For my web videos I got the JVC GR-HD1, it was the first HDV camera to come out a few years ago, and shoots progressive.

You can find it at B&H for $1200, a great deal considering it was a $3000 camera when it came out.

[Soopafresh]

Martin - You've got a unique opportunity to avoid the interlacing/deinterlacing argument altogether.

There are many techniques to address interlacing, but as you've seen and read, there are trade-offs either way. It adds time to your workflow as well - another step.

Write out a list of specific camera features you can't live without, and see if any of the progressive frame ones fit the bill.

Jagabo - "A 50 fps video created this way will contain smoother motion but it's twice as much data to transfer and display"

You'd think so, but the difference isn't that much with compressed video.

[p_l]

My Canon Elura shoots in progressive mode and that's what I use all the time.

I have a question, though. Do DV "capture" programs/utilities (WinDV, DVIO, WMM capture, etc.) preserve my footage as progressive? I know it should be a straight file transfer, but there is the difference between DV Type I and DV Type 2, and I could swear I saw interlacing on some of my raw DV captures, even though I shot in progressive mode.

Is there a DV capture utility that is confirmed to capture progressive as progressive?

[edDV]

My Canon Elura shoots in progressive mode and that's what I use all the time.

I have a question, though. Do DV "capture" programs/utilities (WinDV, DVIO, WMM capture, etc.) preserve my footage as progressive? I know it should be a straight file transfer, but there is the difference between DV Type I and DV Type 2, and I could swear I saw interlacing on some of my raw DV captures, even though I shot in progressive mode.

Is there a DV capture utility that is confirmed to capture progressive as progressive?

DV capture is always 480i/29.97. Progressive can be telecined with pulldown or sent with 24p (advanced).

The lowest end Canon DV camcorder that does true 24p is the XL2. The HD-20 can do HDV 24p but I don't think it supports DV 24p.

The Elura does some pseudo progressive but sends it as 480i/29.97. Which model do you have? Others can probably zero in on how it is done.

A good overview of DV 24p progressive is found here.
http://www.adamwilt.com/24p/

also
http://en.wikipedia.org/wiki/24p
http://www.24p.com/reference.htm

[p_l]

It's this one, which I bought in the spring of 2000, the first Elura model that shoots progressive.



As the review says*, I've been able to extract very nice, uninterlaced stills, but only when I capture with certain programs/utilities. For example, the stills I extract that were captured by the old VideoWave program's capture utility look great (VideoWave itself had an infamous audio sync bug that made it useless), but stills that I extract from captures with some other programs (I can't remember which exactly, maybe some of the ones I mentioned earlier) have visible interlacing.

*The Elura features progressive scanning, which means that you can set it up so that instead of recording 60 fields per second, the Elura will record 30 whole frames a second. This makes each of the 30 frames more suitable for capturing a still image than a still from a video recorded normally. On the downside, when you record video in progressive scan mode, it will sometimes appear jerky, particularly in low light conditions.

[jagabo]

My older Canon Opture PI does 30p an 30i. The only difference between the two is whether both fields of a frame were taken at the same time or if there is 1/60 second between the two. With NTSC 4:1:1 DV there doesn't need to be any other difference -- every scanline is independent of the others (unlike PAL DV which is 4:2:0 and requires special handling of the chroma channels).

Sounds like p_l's Elura is the same.