Media 100i: Is a 768 environment meant to be used 16:9?

[Floh Peters]

There are only a handful reasons for working in 768 these days. I would strongly recommend to work in 720 unless you either have a Vincent or Vincent 601 board (which don

[Danny Jenkins]

Thanks! I thought this was the case. Will upgrading to the new media 100 make it easier to work in 720? I’ve been pushing my boss for a system upgrade and the more reasons I have the better!

[Floh Peters]

[Danny Jenkins] “Thanks! I thought this was the case. Will upgrading to the new media 100 make it easier to work in 720? I’ve been pushing my boss for a system upgrade and the more reasons I have the better!”

The new systems only digitize/acquire into 720 formats. But the big advantage you have with the new systems is that you can mix 720 and 768 media in the same timeline. So if you have a lot of old material in 768 you still can use it without problems, mixing it in realtime with new 720 material.

[Danny Jenkins]

Well it turns out I have the Vincent junction box…the board has “14210 Vincent Junction Box V Rev 3” written on the label on the side. Does this mean all hope of working easily in 720 is lost?

[Floh Peters]

The junction box does not matter, it is the board that counts. There are 3 different boards: the “original” Vincent board, the Vincent 601 and the P6000. If you go to the “About Media 100” window in the Application, there should be a “hardware” tab. I think there you can find the type of your board.
Additionally, if you can set your resolution to 720*576 or 720*486 you most likely will have a P6000 board.

[Chris Zwar]

Just to add some background to Floh’s wisdom, because I’m procrastinating:

When Media 100 first came out the far majority of people were working with analogue video, and even if they were working with digital video it was digitised through analogue connections (ie. component). The Media 100 cards were essentially analogue to digital converters, and the Media 100 system did it better than any of their competitors at the time.

Because Media 100 was converting the analogue video into a digital file, and the Media 100 was also converting that digital file back into analogue video, there was no compelling reason for Media 100 to follow anyone elses digital standards-eg D1 rectangular pixels. In fact as all computers work and display square pixels it made a lot of sense for Media 100 to digitise video as square pixels, so working with After Effects and Photoshop was much easier. As the ratio of a standard 4×3 TV is 1:1.333, and PAL has 576 vertical lines, you can see that 1.333 x 576 = 768 square pixels. That’s where the number comes from.

But as digital video technology became more accessible through DV, and digital betacam continued to become more widespread, Media 100 was upgraded to accept both SDI and DV digital video directly. Because there was no analogue to digital conversion, digitsing SDI and DV was just a matter of shuffling data around, and so the Media 100 system was adapted to work to the broadcast industry’s digital standard of 720 rectangular pixels. If you are digitising SDI or DV you have no choice but to capture at 720 pixels, 768 is simply not an option.

The squashing you refer to when working with widescreen footage is again normal and the industry standard. All widescreen video (standard def) still has 720 horizontal pixels, they’re just stretched out more than the ones in a 4×3 image. If you want to produce widescreen material with square pixels you need 1024 of them, not 768, and even then you have to squash those 1024 pixels down to 720 before you can output them via Media 100 because – just to repeat it – the industry standard for digital video has 720 horizontal pixels, for both PAl and NTSC, and 4×3 and 16×9 video.

So to sum up – 768 pixels is a legacy from the old days of working with analogue video. If you are working in a purely digital environment you can’t even select 768 pixels as a digitise option. The number of horizontal pixels – 720 or 768 – has no relevance to 4×3 or 16×9, as either way they have to be stretched and squeezed as you describe in After Effects. If you are working with analogue video then it’s best to use 720 pixels as you can then mix and match your footage with other digital sources if you need to.

Anyway I hope this historical background helps you understand where 768 fits in. i have to get back to work…

-Chris

[Floh Peters]

Very good explanation, Chris. Just a short note about your “The number of horizontal pixels – 720 or 768 – has no relevance to 4×3 or 16×9, as either way they have to be stretched and squeezed as you describe in After Effects”.
While this technically is correct, the big advantage is that AE has presets (for pixel aspect ratio interpretation and for Compositions) that can handle 720 Widescreen automatically. For 768 material you would have to set up these manually.

[Danny Jenkins]

Great info guys! This helps me understand alot, as I have been working on a very analogue system (old media100i, SP betacam, digitizing via component in 768) and trying to cope with being surrounded by DV media and software.

Since reading up on this I took a good chunk of time to set everything up and have got my system working perfectly with 720! Good integration with media100, Photoshop, after effects and boris graffiti. Feels like a great weight off my shoulders! Now I just wish I had the new media100 capability of mixing 768 & 720 in the same program! Hope we will be upgrading soon!

Thanks again!