WHAT IS HD VIDEO?
We shoot almost exclusively with the state-of-the-art professional broadcast Sony XDCAM EX HD cameras in what is called ‘full high definition’ or ‘full HD’ at 1920x1080p resolution. This may seem like overkill to you if all you want is a corporate DVD or some web video content shot – but it isn't. And if you want to understand why, read on.
Since the late 1990s standard definition (e.g., digital video or DV) camcorders have dominated the video production industry. Various formats exist, some of which are more robust in data capture (such as DVCAM) but they all produce at best 720 x 576 pixels of resolution (actually it is 625 horizontal lines, not 576, but not all are visible or used for video). Also, DV uses the interlaced field format suitable for traditional cathode ray tube televisions but these are rapidly being supplanted by flat-screen LCDs.
Seven years ago high definition video (HDV) hit the market. This was a step up in resolution to 1440x1080 interlaced (or sometimes 1280x720 progressive). Compared to DV, the potentially greater number of pixels of this format provides a better image in resolution. However, HDV cameras suffer from very high data compression rates (in both video and audio) which causes unsightly artefacts in the picture (e.g., tiny blocks and serrated edges in fast movement) and compressed poor quality sound. Until very recently, these cameras also had poor performance in low light conditions (leading to unsightly video noise and softening of the image). However, used correctly and within their limitations, good results are achievable with ‘prosumer / lower end professional’ cameras such as the Sony Z1 and Sony V1 or smaller Sony HC1 (I’ve used the latter two extensively in the past - so I know this first hand). A more recent consumer HD format, AVCHD, has also emerged, but this is only just beginning to be suitable for professional use (due to some limitations similar to HDV) and does not have the quality of colour reproduction we like to see and so I won’t discuss it here.
XDCAM EX – the HD format used by Shooting Image Ltd - what this means for you
Within the last three years, Sony released the XDCAM EX format that we use (initially with the PMW EX1 and the newer PMW EX3 that we own). This full HD format (1920x1080 progressive) uses a much higher data rate than HDV, and much better imaging sensors resulting in class leading sharp images, accurate recording of movement without artefacts and vibrant clear colours (even in low light conditions). These cameras use very high quality optics to ensure minimal degradation of the image as it reaches the sensor and feature critically important tools that allow precise and accurate focusing. In addition, unlike HDV, the XDCAM EX format allows for uncompressed audio recording, resulting in high quality and clearer sound – and sound is as important as the picture! And finally, the format is fully solid state, recording directly to memory cards, so there are no quality problems with tape dropouts. The solid state workflow allows fast and effective reviewing of shot video and subsequent editing on our Apple Mac Pro and MBP computer systems.
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The XDCAM EX format – used by high end independent film and documentary makers like us – is often used by the BBC HD and National Geographical HD channels. Formats such as HDV are restricted to only a small proportion of the total programme content (typically 15% maximum) due to its lower resolution and quality. With these EX cameras, Sony have targeted the niche of videographers who demand the highest picture performance available in this size of camera.
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Yes, yes, but all you want is a standard definition DVD and a short Flash video infomercial to play on your website – all of this is totally irrelevant, right? Well, not quite actually and here’s why I believe it is important.
By capturing and editing video in broadcast quality high definition, we create a superior quality master, even if we down-convert the final video output to standard definition. Importantly, the video is also likely to remain usable as the master can be used at a later stage in the life of the finished product as more and more HD content becomes the norm. Even now, there are already websites hosting HD video for free and for anyone to watch – Vimeo, Exposure Room etc. Even YouTube started offering HD video in November 2008.
The rise of HD video on the web is unstoppable, as everything becomes cheaper, faster, and more ubiquitous – fast PCs, huge disk capacities, large high resolution monitors, and broadband. There is also an explosion of mobile video on phones and personal media players and pocket internet tablets, iPods and iPads etc. - our HD video master files can be easily converted to any format for playback on any of these portable devices as this revolution unfolds before us.
Sure, all that’s great technology but it’ll never overcome not pointing the camera at the right things, at the right time, being in focus, exposing correctly and capturing great sound. And on top of that, then there is the power of editing, what to include and what not to ensure the clarity of the intended message.
Well, we try and get all that right too and most of the time I believe we do.
Copyright © 2010 Andy K Wilkinson PhD
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Wikipedia: High-definition video
Sony XDCAM EX
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