Prepping 1080 graphics to end up on SD DVD?

[Chris Brearley]

Personally I would create the graphics in a 1024×567 (or 1050×576 – I think DVD SP still uses 1.422?) comp and export them as a 720×576 QT MOV using the animation codec. As far as fields go, that depends on the look you want. You can render from after effects with upper field first but I think this creates more of a “videoy” look which I don’t like. I usually render without fields and let the DVD authoring software split it into fields. I prefer this look even though it won’t be as smooth looking, I think it resembles film more. Hope this helps.

[Guy Thompson]

You have a few things to consider:

1. Do you need to combine motion graphics with interlaced video?
2. Does your final SD DVD need to be interlaced?
3. All of the fields you have in 1080i will not translate into SD.

A sports programe for example may need to be 50i to retain really smooth motion, but most other projects would ideally be de-interlaced for output to SD.

Combining animated motion graphics which are 25p with footage in FCP which is 50i will produce strobing on an interlaced CRT TV, but you will not see it on an LCD which is progressive. (Even if your source is interlaced)

To make an interlaced master, I would work in AE at 1920×1080 square pixels at 50fps. When you come to render your HD master, render at 25fps Upper field first. (Or at least matching the field order of the HDV)

Another alternative is using Magic Bullet (or similar tool) to de-interlace your HDV footage in AE, then you can create a fully progressive HD master. That would be my best choice. (Tip: de-interlace each shot, not an edited sequence for best quality results)

Then you can just use Compressor/DVd Studio Pro to down-res the MPEG2 for the SD-DVD.

If you project is longer than 5 minutes, I’d probably down-res the footage first and create my entire master at SD, if it’s never intended to be seen as HD, it could be a more time-consuming process for rendering. Then you know your SD master is perfect before putting to DVD.

This is by no means a perfect workflow, I’m interested to see what other people’s approaches.

[Chris Cummings]

Thanks so much for the info Guy.

Just double-checked the sequence specs…the frame rate is 29.97, 1440 x 1020, HD 1440 x 1020 PAR. I’m doing a title sequence that can stand on its own, but I have to do lower thirds that are, of course, integrated with the footage.

Part of the difficulty is this job came through a friend who is dealing with the client, and the client doesn’t know anything about this stuff – they just need a couple DVDs to take around for presentations. I’d love to just deinterlace everything (good info BTW, thanks), but probably safest to keep it all interlaced in case it’s used on older TVs?

Cheers,
~Chris

[Chris Cummings]

Cool, many thanks for the info Chris! Just to confirm, this is keeping a square pixel aspect ratio, and these dimensions will allow DVD SP to convert it properly during encoding?

[Guy Thompson]

Deinterlacing everything will allow you to control the look better in AEFX and ensure you graphics are working perfectly with the footage.

1440×1080 is the pixels which a Sony HDV camera actually records, the frame size is 16×9, so you can safely de-interlace your footage and scale everything down to 864×486 for NTSC D1 wide screen square pixels. (Then scale to 720×486 NTSC in your render output settings)

A progressive master will look a lot better than weird HD field mush if you get it wrong.

You can even just separate fields in your interpret footage settings for the HDV. Half of 1080 is 540, so that is still plenty of res when your NTSC frame size is just 486 high. Just scale it down and maybe sharpen it a little.

Note:

You would only ever stay 1080i if you were delivering an interlaced HD master. And even then, the rendered image can be progressive, you just don’t want to mix interlaced footage with progressive GFX. It must me consistent.

[Chris Cummings]

Got it, thanks so much for the info Guy, and taking time to respond. I truly appreciate it.

All the best,
~Chris

[Brendan Coots]

Just wanted to add a quick note to this thread. For NTSC, the DVD spec calls for 720×480 video, not 720×486 D1. If you output to 720×486 DVDSP will scale the video down (and not very well) so you will lose some quality unnecessarily. The proper dimensions would be 853×480 (square pixel widescreen) or 720×480 with the correct PAR applied.

Brendan Coots
Splitvision Digital
http://www.splitvisiondigital.com

[Chris Cummings]

Thanks Brendan – I always wondered about that as well!

Cheers,
~Chris

[Jimmy Brunger]

Just to throw something in…I’ve done numerous adverts/programmes (in PAL) with interlaced SD footage and progressive GFX overlaid – works fine on any type of TV that I’ve seen.

We also down-rezzed 1080i to SD PAL 50i no problem all the time, with no field probs. We used a HDCAM vtr to play the HD master out via SD-SDI to the drives. Maybe the vtr handles downscaling interlaced footage better? We always used to shoot on HDCAM for future use, but always captured and edited at SD res.

As a side, don’t forget HD is square pixels and SD PAL/NTSC is not. Just directly scaling down GFX means you’ll get a very slight distortion when output on a TV. Watch circles are still circles..!

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[Chris Cummings]

Great info as well – thanks for the add Jimmy.

~Chris