HD Producer Primer
At the HD day at SATIS, the annual Paris based exhibition for all things audiovisual, I must have spent a good ten hours in conferences and screenings, not to mention fifteen minutes at the free bar.
During that time I attended several sessions, and talked to numerous proponents of HD about everything from compositing to conversion. Later on I'd promised to meet up with a producer friend of mine, which was refreshing, as unlike many of my other colleagues, she refuses to speak in maths.
I found her very frustrated at having attended a session on "Emerging HD markets for Fiction & Documentaries", which had apparently descended into a dull geek-off.
You see, she is of the opinion that you don't explore a new medium by breaking it down in to its constituent and quantifiable parts. "What does a sculptor do with a block of ice?" she said, and they don't put it under a microscope to see what it's made of.
She's right, of course, but I still offered her a word of caution, explaining that there are many technical considerations when working with HD, and if you haven't considered your Post Production path before shooting, you're in trouble. "Yes" she replied, "but I commission work, I need to think about pitching ideas, content, budgets, distribution and most of all, people. I'll bet you there are only ten things I need to know about producing in HD, aren't there ... Dave?"
This one then for all you ice sculptors out there, go and put your goggles on:
One: What is it?
The term HD (Hi-Definition) applies broadly to all video formats with a resolution greater than that of Standard Definition video, whether they be analogue or digital.
In reality, the term HD refers to two distinct forms of digital video, each with different resolutions, but both sharing an aspect ratio of 16:9. They are commonly referred to as '720' and '1080', each term representing the number of vertical lines of resolution in their respective signal.
The formats are often described by their respective pixel resolutions, for which "720" contains 1280 horizontal pixels and 720 vertical pixels, and similarly "1080" contains 1920 x 1080 pixels.
Two: Interlaced or Progressive?
Furthermore, HD may be captured either in interlaced (i) or progressive (p) form.
Using the interlaced method (i), lines are displayed in two separate fields (phases) where the odd numbered lines (upper field) are displayed first, followed by the even numbered lines (lower field). The two fields combine to form one full frame of video.
Progressive scan (p) on the other hand denotes video which is displayed one full frame at a time, similar to film which provides 24 frames per second (fps), and as a result appears to flicker slightly.
Thus when describing an HD format, one might say '1080i' or '720p' where the i or p denotes interlaced or progressive.
Three: Frame Rates
The third element that the producer should be aware of is frame rate. Producers should select a frame rate applicable to their target broadcast platform, or geographical market.
HD in its various guises supports a number of different frame rates, including 24fps (similar to film), 25fps (similar to PAL) and 29.97 (similar to NTSC).
Figures denoting frame rate are often added to the format description, e.g. 720p24 indicates a frame rate of 24 fps (frames per second).
Often when the format is interlaced, it is the field rate which is added instead. 1080i50 denotes 50 fields per second (where two fields combine to make up one image frame). This is equivalent to a frame rate of 25 fps.
See, simple!
Four: Flavours of HD
Good DPs and cameramen with the right experience will ensure consistency across multiple shoots, because although it is possible to mix and match formats and frame rates in post, you should try to avoid it.
You'll also have to contend with the many flavours of HD based on the offerings of each of the manufacturers.
For example, Sony"s HDCAM format which is 1080 and supports multiple frame rates including 25p, 50i, 60i, and 30p (beware that not all cameras in the HDCAM range support all frame rates). Alternatively, Panasonic's DVCPRO HD supports 720i, 720p and 1080i standards.
Much has been said recently too about Sony"s HDV format, but despite supporting both 1080i50 and 1080i60 it is incomparable to true HD due to the high level of compression.
Be aware too that when submitting HD programmes, most broadcasters are wary of material originally shot in HDV, as in the case of one US broadcaster who stipulates that a HD show “should be no more than 30% HDV.
Five: Arguments for producing in HD
As a producer you may need to convince your boss or sponsor that HD is the way to go on your particular project.
The obvious argument is that HD offers vastly superior picture quality over SD. If viewed on an HD monitor or HD television, colours are vivid and don't bleed, and detail looks stunning, right throughout the impressive luminance range. There is over five times more information in a HD frame than in a SD frame.
Secondly, production budgets do not need to be vast. Others have calculated that the cost of a HD shoot is on average only around 10-20% higher than an equivalent Digibeta shoot.
Possibly the greatest argument for shooting HD is that you are future proofing your content; content which may ultimately be destined for HD broadcast or HD disc media, so if your show has a shelf life of longer than a couple of weeks, shoot on HD!
Lastly, when selling your programme, broadcasters are willing to pay up to around 30% more for native HD shows. Note that the market for TV is rapidly becoming the market for HD.
Six: Downconversion
If you post produce in HD you will have made an HD master ready for when it can be broadcast in HD. But in the short term you may want a SD (Standard Definition) version so that it may be broadcast today. Therefore you will need to have your programme downconverted. There are a number of ways to do this and it should be handled by a suitably equipped post house. Just know that as it’s at the end of the process, where deadlines may be tight, it’s something you should build in time for.
Seven: Upconversion
In the case of documentaries especially, where you'e relying on archive footage to form a good percentage of your programme, you will need to have the footage upconverted.
Again this is the job of the post/facilities house and there are a number of ways to do it depending on the format of the original material, and the target HD format. Get good advice from those who've done it before, and build it in to your budget.
Eight: Geographical Markets
Different countries have different preferences in HD format. Your desired target market should help you decide in which format to produce and post your programme.
In Japan for instance, where there is already a plethora of HD broadcast channels led by NHK, everything is 1080i.
In the US, things are a little more cloudy. Certain broadcasters have a stated preference for 1080i and others 720p.
In Europe, other than Belgium based HD's service, HD broadcasting has been slow to begin. As launch is imminent in France, Germany and Austria, and in early 2006 the UK, we'll soon know more about European broadcasters' stipulated preferences.
Arguably the safest format in which to produce is 1080p25, from which you can easily create a 1080 interlaced version, and from which you can downconvert to SD PAL, which shares a 25 fps frame rate.
Nine: Disc media
In terms of DVD distribution, know that the current DVD standard only supports Standard Definition resolutions. Therefore despite your programme having been produced in glorious HD, it will have to be downconverted to SD before inclusion on a DVD. This may be done at the encoding stage or downconverted beforehand.
Do not fret, however, it will still look way better than had it been shot in SD in the first place, and in any case it won't be long until there are HD disc formats which support HD.
In fact, two formats, Blu-ray and HD-DVD, are currently fighting it out to be the HD consumer disc of the future. Which one do you go with? don't worry about that for now, just be sure to keep your HD master on tape for when the time is right.
Ten: Trainspotting
Some view HD as a revolutionary medium, some as a new broadcast standard, and to others it's just another technology wave.
Whatever it is though, the tenth and final thing you should know about HD is that it's coming like a train, no doubt bullet-shaped and soaring suspended over a magnetic field at 300mph.
And if you're travelling on it any time soon, come and say hello. I'll be in the buffet car.
Dave Brewis