What is so great about 50P???

[Chris Harding]

Hi Guys

I have been shooting 50P as everyone says it's so great then someone else comes along and says why are you shooting 50P??? Shoot interlaced.

Now, what is so great about shooting progressive and double frame rate ...has anyone got a sensible answer as to why it's such a great format to shoot in or is it just the "in thing" ????

Comments would be appreciated.. good or bad on either interlaced or progressive!!

Chris

[Craig Parkes]

50p has tangible benefits. If you want to do a temporal distort (slow mo etc) then having more complete frames, rather than interlaced frames, makes this easier.

Also, exported still frames are easier because you will have complete frames rather than two half frames joined together, o the resolution is morw what you see is what you get (except for horizontal pixel aspect ration in some fomats mking this less true in te horizontal aspect.)

On the web everything is progressive, so if you are shooting interlaced the you are going o have to deinterlace for web distribution, which means you tend to lose both vertical and temporal resolution, which goes some way to negate the difference between 1080i and 720p.

Ultimately, for tv anywayno one actually watches interlaced footage, all lcd/plasma tv's process interlacing out to progressive pictures anyway, so with 50p you might be avoiding the hoops they jump through to do this (or might not, many tvs/digital receivers might take your 720p50 footage, upres it and interlace it on one chip to 1080i25, then deinterlace the 1080i on output to the panel.)

Long story short is the advantge of 720p50 is that at your end at least, if you have non interlaced viewing conditions (such as a crt or high end broadcast lcd monitor which 'fakes' he interlacing) the you see what the pictures will actually look like in motion. If you watch 1080i then you won't know how the motion characteristics of the footage will be until after you deinterlace it, and if you deinterlace to begin with then you end up with half the temporal resolution than 720p, and actually less vertical resolution (kind of, at worst 540 vertical versus 720p, depending on how you do the deinterlacing.)

Now, there are some more downsides to 720p50 that people may not mention. One is timecode. Moving to a 50fpsTC versus 25tc which people are used to in pal countries can cause some headaches. Like editors might have effects presets for 6 or say 12 frame transitions, which are now all too short when they are working in 50p ad need to be doubled, this cam be suprisingly annoying for someone who cuts regularly, but doesnt cut 50p material often. This isn't a technical issue, just a workflow one.

There is a perception that 1080i25 will translate better ono an SD interlaced timeline. This may or may not be true, depending on your edit suite/workflow. It sholdn't be true, but I know in final cut if you drop 50p footage on a 25i timeline it just treats it as progressiv and throws away every other frame, in which case you WOULD have been better of shooting 1080i25, but if you work with the footage properly then you should get better results going to SD from 720p50 compared to 1080i25, however the workflw for this can be more difficult hn it needs to be depending on which nle you are using.

(looking back this has a stupid amount of typos - damn iPad.)

[Buba Kastorski]

to make it really short, progressive has complete frame and interlaced field is just a half of the picture, so would you rather have more video data then less? Plus to my eye progressive looks less videoish

[Chris Harding]

Thanks Guys

Craig I do like tangible results rather than people saying "it looks better" ... From a workflow POV it does mean that you don't have to worry about de-interlacing if you are rendering down to SD which with weddings I unfortunately need to do as most brides still have DVD players only!!

Your opinions are much appreciated!!

Chris

[Craig Parkes]

Hi Chris, actually, if going to DVD you also get to decide whether you want to deliver it as interlaced footage.

If you like the progressive look, you can go that route at 25p in an interlaced container by simply throwing away every other frame and encoding the now 25p frames for DVD (DVD's are always interlaced, but the footage may be progressive in an interlaced format).

Or if you want an interlaced look, 50P can give you that by downressing every frame to 720x576 (anamorphic) then interlacing those frames to turn them into fields, then encoding that 25i video for your DVD.

If your main interlaced deliverable is DVD, then 720p50 gives you the best options in my opinion.

[Chris Harding]

Thanks Craig

Looking at my early August wedding done in 720 50P and last weekend's done is 1080 i I think I like the overall result from the 50P footage!!

All your comments are very much appreciated!!

Chris