I looked a couple of cameras recently that only shot 50i footage, and bega to wonder why someone would shoot, or select a camera only capable of interlaced footage.

In the UK, the majority of TV sets will be plasma, LCD and LED displays.

Computer monitors are LCD for the most part

So since these diplays cant show interlaced footage anyway, what benefit is there to shooting interlaced?

Thanks guys
James

In the UK HDTV is broadcast as interlaced 1080. It really depends on what you're shooting and who you are shooting it for, some types of TV programme are shot 1080 50i, rather than the more filmic 1080 25p. For example the commonly used Grass Valley LDK 6000 studio and OB camera can only do 1080 50i, rather than 50p. It can do 720 60p but won't do a similar fame rate with 1080.

Hi

I looked a couple of cameras recently that only shot 50i footage, and bega to wonder why someone would shoot, or select a camera only capable of interlaced footage.

In the UK, the majority of TV sets will be plasma, LCD and LED displays.

Computer monitors are LCD for the most part

So since these diplays cant show interlaced footage anyway, what benefit is there to shooting interlaced?

Thanks guys
James

50i footage is used for the same reason it always has been, bandwidth considerations, whether that was analogue TV or now digital. It allows for 50 samples a second to give smooth motion but throws away half the picture information in the process.

Things in the digital world with compression codecs we use now blur this argument a bit that it's less data, as some will say you can compress 1080/50p easier than 1080/50i, which is essentially true, although it falls apart a bit at the data-rates terrestrial HD TV works at which struggles already. Most dramas are now broadcast in HD at 25p as it holds together a bit more over the low data-rates we get into our homes.

In terms of acquisition, it does seem crazy not to capture at 1080/50p, as this gives you two options for distribution later as it doesn't force 1080/50p to be used as the output. 1080/50p is easily converted to 25p or to 50i, and also to 720/50p for Blu-ray. Later you have the original footage in 1080/50p when technology progresses and it becomes standard.

Regards

Phil

There's a good reason I shoot 1920/50i in my Sony NX5, and that's because at the poke of a screen I can be slotted into the sweetly smooth, 4x slower slo-mo mode. If you're shooting in any progressive mode the slo-mo is denied to you.

tom.

Hi

There's a good reason I shoot 1920/50i in my Sony NX5, and that's because at the poke of a screen I can be slotted into the sweetly smooth, 4x slower slo-mo mode. If you're shooting in any progressive mode the slo-mo is denied to you.

tom.

Of course this only applies to 1080/25p/24p, but in the context of 1080/50p doesn't apply. 1080/60p/50p gives you better slow motion as more information is captured. If your target is 30p/25p you can slow it down by 50% with no processing, de-interlacing or frame blending required, this gives brilliant slow motion with full progressive frames. Any other slow motion speeds will always be better as no de-interlacing is required prior to changing the frame rate and you have much more picture information to start with.

Regards

Phil

Interlaced has some uses - at least in sports.

I must admit I shoot all my weddings interlaced..good ole 1080 50i ....it might not be the best format but I have have any issues or complaints from brides and the results are super dependable!!!

I shot a few weddings this season in 720 50P and I must admit you get nice stills from the timeline without any need to de-interlace but on closeups I was finding that my HMC's had pixellation of the image in a few places ...especially during closeups and they always seemed to appear on the bride's cheek!!!
(face not rear end!!!) Once rendered to SD DVD you couldn't see them BUT they were there!!!

I have probably shot close to 200 weddings in HD now and all but (I think) three were 1080 50i and the results were always great.

I guess I would try out progressive formats on events that were repeatable but with weddings you can't say "Could we please do that again??"

It might not be technically the best or creative BUT interlaced does give you a guaranteed result!!

Chris

I'm with Chris on this one...

As soon as AVCHD 2.0 standard (which includes the 'new' 1080@50P/60P standards from Sony/Panasonic) has proliferated (meaning, for me, it's an easy ingest into FCPX without needing ClipWrap) then all I'll ever shoot is progressive. A day I've been waiting for, for the last decade or so.

I favour "frames" over "fields" any day of the week. No more combing workarounds needed.

I must admit I shoot all my weddings interlaced..good ole 1080 50i ....it might not be the best format but I have have any issues or complaints from brides and the results are super dependable!!!

I shot a few weddings this season in 720 50P and I must admit you get nice stills from the timeline without any need to de-interlace but on closeups I was finding that my HMC's had pixellation of the image in a few places ...especially during closeups and they always seemed to appear on the bride's cheek!!!
(face not rear end!!!) Once rendered to SD DVD you couldn't see them BUT they were there!!!

I have probably shot close to 200 weddings in HD now and all but (I think) three were 1080 50i and the results were always great.

I guess I would try out progressive formats on events that were repeatable but with weddings you can't say "Could we please do that again??"

It might not be technically the best or creative BUT interlaced does give you a guaranteed result!!

Chris

Thanks for the replies guys.

Chris, this is my kind of thinking too. Interlaced is tried and trusted, so im wondering now if theres much of a reason for something like wedding videography to switch to progressive.

My initial point was that most displays in the UK ae no going to be LCD/plasma type so interlaced footage will in the end be deinterlaced for display on these diplays.

I suppose my intital question could have been, is there a reason NOT to shoot interlaced any more lol

I think when 50P is standard that will would be the best overall...

James

I think the real question here is that if you don't shoot interlaced - what do you shoot?

OK, simple answer is progressive - but practically (in the 50Hz world) that means 720p/50 or 1080p/25? Which of those do you choose?

Choose 720p/50 and you maintain the smooth motion rendition - but have to accept a resolution drop. Choose 1080p/25 and you keep max resolution (better than 1080i/25, in fact) - but have to accept "jerky motion".

There is no simple answer. Yes, the hope is for the "best of all worlds" 1080p/50, but in the meantime a lot may depend on what you're doing. Some people may currently have SD and DVD as the prime "here and now" market, but want an HD master for possible future use. Here, 720p/50 may have a lot going for it. It's keeps the "smooth motion" of 1080i/25 - but compresses better (that's the beauty of progressive in the digital world), and is best for downconversion to SD - every SD field is formed from a discreet HD frame. Easy - whereas using interlace as the original makes for a far more messy deinterlace, downconvert, reinterlace.

I've been thinking about this myself - I don't like 25p (looks awful to my eye unless motion is pretty static) so that leaves 50p which is great but still impractical. End of argument for me, for now, its 50i despite the problems.

A question.

I shot half a documentary at 1080p25 (in a 50i wrapper).

Now i've updated my camera. It shoots 1080i50, but not 1080p25 (the opposite of my old camera). I presume mixing the two framerates will look pretty bad and I should continue using the old camera for the remainder of the doc. New camera has better audio, better low light, and a few other upgrades.

I'm hoping to sell for PAL broadcast (so 50i).

Any advice?

Any advice?

Final project at 25p.

Hi

I think the real question here is that if you don't shoot interlaced - what do you shoot?

OK, simple answer is progressive - but practically (in the 50Hz world) that means 720p/50 or 1080p/25? Which of those do you choose?

Choose 720p/50 and you maintain the smooth motion rendition - but have to accept a resolution drop. Choose 1080p/25 and you keep max resolution (better than 1080i/25, in fact) - but have to accept "jerky motion".

There is no simple answer. Yes, the hope is for the "best of all worlds" 1080p/50, but in the meantime a lot may depend on what you're doing. Some people may currently have SD and DVD as the prime "here and now" market, but want an HD master for possible future use. Here, 720p/50 may have a lot going for it. It's keeps the "smooth motion" of 1080i/25 - but compresses better (that's the beauty of progressive in the digital world), and is best for downconversion to SD - every SD field is formed from a discreet HD frame. Easy - whereas using interlace as the original makes for a far more messy deinterlace, downconvert, reinterlace.

720/50p looks extremely good, I've been burning 720/50p to Blu-ray from 1080/50p footage. Resizing square pixels to square pixels with no de-interlacing required (as it's all progressive) works extremely cleanly and the results are very good.

The plus with 1080/50p is you have two choices for easier compatibility now, you can interlace to 1080/50i or resize down to 720/50p, and both these formats can be obtained from 1080/50p very easily, and you have the original footage for the future. When editing then effects, picture adjustments, resizing, fancy transitions etc all work better on progressive footage.

Don't forget that 1080/50i is really 1080/50p with half the picture detail thrown away in each frame, it's essentially the crudest form of lossy compression that has been around since the dawn of TV, time to say good bye to it.

Regards

Phil

Hi

A question.

I shot half a documentary at 1080p25 (in a 50i wrapper).

Now i've updated my camera. It shoots 1080i50, but not 1080p25 (the opposite of my old camera). I presume mixing the two framerates will look pretty bad and I should continue using the old camera for the remainder of the doc. New camera has better audio, better low light, and a few other upgrades.

I'm hoping to sell for PAL broadcast (so 50i).

Any advice?

Should be absolutely fine, the BBC do this all the time, if you watch BBC HD and have equipment that shows you the encoding method in real time, you can see dramas etc switching between between interlaced and progressive all the time.

You should treat all your footage as 50i, that's the reason we have 25fps in a 50i wrapper, so you can easily mix progressive and interlaced.

You should render out as 50i.

Regards

Phil

Thanks Phil!

I didn't realize the beeb did that, but good to hear that footage can be mixed and still look good. If only I had a PAL interlaced monitor down here I could do a little test mixing 25p in 50i stream with true 50i - all rendered out at 50i - to see what it looks like ...