1080i 30 frames

[Don Greening]

[Craig Bass] “This is probably going to come off sounding ignorant, but how is it that the XH-A1 can shoot at 1080i and 30p?”

It doesn’t sound ignorant. The numerous formats and the way they’re advertised these days is confusing, to say the least. Canon’s are even more confusing in that their progressive mode is actually called 30F instead of everyone else’s 30p. The A1 shoots in both interlaced and in “frame mode”. Interlaced NTSC mode is referred to as 60i but is actually shot at 59.94 “interlaced” frames per second to conform to the NTSC broadcast format. Canon’s frame mode takes two interlaced frames every 30th of a second and combines them to form a single complete frame every 30th of a second and then records that to tape. But the 30F mode is actually shot at 29.97 complete frames per second to again, conform to the NTSC broadcast standard. Confused? Yeah, I know. True progressive mode is where the camera has actual progressive imagers and records one complete frame every 30th of a second (actually 29.97 fps) to tape. This is known as 30p.

– Don

[Craig Bass]

So, due to the fact that 30F mode is, in a sense interlaced, there is no issue with it interfacing with the 1080i setting? Am I on the right track?

Most of what I shoot is destined for SD DVD and webcast; however, there is always the possibility that it will be finalized as an HD DVD: with this in mind, what are the settings you would suggest? Up until this point, I have been shooting on 1080i 30F.

Thanks for taking the time to provide me with an answer. It is much appreciated.

*Craig*

[Don Greening]

[Craig Bass] “Am I on the right track? “

Mmmmm, not really. 30F is Canon’s version of progressive shooting, so it is essentially one complete frame of video compared to interlaced, which is 2 fields of video per frame. That’s the fundamental reason why interlaced is referred to as 60i and 30F is well, 30F. If you mix the two in the same timeline you’re going to have to change one or the other to match. If your final delivery is for the web it’s always better to shoot in frame mode because computer screens display video in progressive format. If you shoot for SD DVD personally I would still shoot with the A1 again in frame mode because today’s HD plasma and LCD TV monitors handle progressive video better than interlaced. This last bit is just my own observation. To satisfy your own curiosity you might consider doing a test using both modes and judge for yourself what looks good on today’s televisions.

Hope this helps.

– Don

[Tl Westgate]

I just found out something interesting. If you shoot in 24F (and probably 30F) mode on the A1, uncheck Frame Blend on your clip in the timeline!

— TL

[Don Greening]

[TL Westgate] “If you shoot in 24F (and probably 30F) mode on the A1, uncheck Frame Blend on your clip in the timeline!”

What happens if you don’t? Just curious, as I don’t use any Canon HDV cameras.

– Don

[Tl Westgate]

Frame blend, from what I understand, blends the frames of interlaced footage so it’s easier on the eyes. However, with progressive footage, it tends to blur things up instead.

— TL

[Todd Terry]

Well, what editing platform are you talking about? In Adobe Premiere (i.e., Premire Pro CS3), “frame blend” only has any affect if your clip on the timeline is anything other than “normal”, that is, not 100% speed.

If you speed up a clip (set its speed >100%) or slow it down (speed <100%) then checking or unchecking the "frame blend" box is definitely worth trying... sometimes you get much better results with one vs. the other. However if your clip speed is 100%, it doesn't matter if the box is checked or not... since no frame blending is actually applied to normal speed clips.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[Tl Westgate]

Hrmm, I guess I’m still getting a handle on this A1, then. I shot using 24f mode and am editing in a 29.97 timeline. The frame blend switch makes the footage look bad.

— TL

[Todd Terry]

Canon’s 24f mode should import into a 29.97 timeline just fine, no frame rate chage or frame blending or pulldown removal/addition should be needed at all. Frame blending is typically not for framerate conversion, it is for smoothing out clips that are of different speeds on the timeline, not different framerates. If you have your clip set at any speed other than 100%, try frame blending to see if it gives improved results (sometimes it does, sometimes it doesn’t). If your speed is 100%, leave frame blending off.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[Tl Westgate]

Okay, here is what I’m talking about. I have a 24f video on a 29.97 timeline. This is with Frame Blend on:

And here it is with Frame Blend off:

Even though my speed hasn’t changed, I guess it’s interpolating intermediate frames with Blend on, and duplicating frames with Blend off. I think the Blend off looks better.

— TL