Shooting Video For the Web

SHOOTING FOR THE WEB
by Christina Fox

Downloading a one-minute, uncompressed, full-screen video via a 28.8kbps modem would take 125 hours, according to www.integratedstreaming.com, and presumably that's on a good day. This is why we use video compression, which throws away non-essential picture information using codec (compression- decompression) algorithms.

But, before you even get to the point of deciding which codecs to use, you can reduce your file size simply by paying attention to the way you shoot and edit your material. Shooting for the web does come with its own unique problems but, as with all good productions, problems can be minimised ahead of the shoot. "Plan, plan, plan. Check out everything that is out there on the web and figure out how you could do it better" says C.C. Chapman, co-founder of Random Foo Pictures, producers of independent films.

For minimal file size, the ideal subject is probably a talking head against a bland background in a noise free studio. But, this is hardly going to attract vast numbers of surfers to your site. As satellite TV found out, sport is a real attraction, but it wasn't made for today's Web broadcasting. Fast moving subjects, quick camera movements, fast edits, every time a goal is scored or a point earned the spectators move around and make a noise, forming busy data-rich backgrounds. It's enough to make a codec melt.

Quality Counts
Video quality on the web today may be poor, but it is getting better and will continue to do so. "Get the best equipment you can. Beg, borrow or steal it, but whatever you get your hands on make sure you figure out how to use it and then go nuts," enthuses Chapman. He's right, shooting on the best format you can afford will future-proof your material and give you the option to distribute it through other quality channels too. If your budget allows, go for DigiBeta or Beta SP. DV will also offer high quality, even from low-priced cameras such as the Sony PD150 and Canon's XL1. A FireWire connection not only makes it easier to get your pictures into a computer for editing, but retains the maximum DV quality. If you have no budget, at least try to use S-VHS rather than VHS which will introduce noise and other artefacts which codecs recognise as information and preserve. Compression almost always amplifies noise.

You'll also need a tripod for rock solid shots. The more similar each frame is to the next, and the one before it, the better the final product. Differences mean inefficient compression and loss of detail. Stuart Mountain, Broadcast Journalist at BBC Humberside warns: "Don’t zoom in and out, the end result will be awful. Avoid fast panning. Because the picture will get crunched down whatever system you use to compress it. It all goes blurred as there is too much information."

Set Dressing
Fussy stripes, dots and checks are out. Get your talent to wear low contrast solid colours (but not red or yellow which can cause problems). The preppy look is in.

High contrast busy backgrounds are also out. Plain walls will compress better than chintz wallpaper. Aaron Brown director and editor at Reelized Productions advises that you should "…pay specific attention to patterns in the fore and background. Complex patterns will give a lot of unwanted artefacts, especially if your camera or subject moves. Also, if you are shooting talking heads, put them against a black or dark background. White and lighter backgrounds don't compress as well, and will increase your compression artefacts." If you don't have a choice of location (or wallpaper) then a shallow depth of field will rescue your shoot. Open the camera's aperture to reduce depth of field and introduce a neutral density filter to prevent over exposure. Your subject can be kept in focus while the background is blurred.

Dramatic high contrast lighting is also out . Use soft lights indoors or put diffusers over hard light sources. Shooting at midday in bright sun can cast harsh shadows under chins and into deep set eyes. A Lastolite reflector, or even a simple sheet of polystyrene, can bounce sunlight into those dark shadows and reduce contrast.

Sound Advice
Low budget shoots try and dispense with the sound recordist and record sound from the camera's front mic. This is a big mistake. As your picture quality reduces so sound quality becomes even more important. Audio codecs can amplify undesirable background noise, so this must be reduced as much as possible on location. Turn off air conditioning units in offices, switch off muzak and don't work beside busy roads. You can always add sound effects in post. Get your microphone close to the sound you want or use a highly directional mic.

If you can only afford one microphone, buy a gun mic. These directional (hypercardioid) mics can, if positioned correctly, pick out a voice even in noisy surroundings. The Rolls-Royce of gun mics, beloved of sound recordists, is the Sennheiser 416. It is expensive, but will probably outlive the camera. Sennheiser produce a cheaper alternative, the ME66/K6 or check out Beyer's MCE 86NCS. Gun mics are susceptible to wind noise, so they should always be used with a wind cover such as The Rycote softie.

Stuart Mountain believes you should "keep the bit rate down and try not to be too clever with the stereo. 16-bit rate in mono gives good quality sound. Whereas with 16-bit stereo you will have problems. You'll loose bits of audio and video." Random Foo Pictures records mainly in mono. "Lots of music and audio in general can suffer on the Web so just keep this in the back of your mind. Which is more important? The audio or the video? If it's both equally then the file size will be bigger and on the web you're always trying to make it smaller and thus quicker."

4:3 or 16:9?
"The majority of our stuff is 4:3 with a few exceptions," says Chapman. " I'm actually filming something right now called Maven which is being shot in 16:9. Does it matter for the web? I don't think so, since no matter what, you're going to be viewing it much smaller than you usually would. But, then again, you see things like what they just did at BMWFilms.com which was totally new for the web and they did an amazing job with that site."

During editing, it is worth cropping the first and last few lines from the top and bottom of the picture, which usually contain noise (taking care not to remove any information you do want).

No matter what aspect ratio you decide upon, the overall screen size will be small. Close up shots will give the viewer a better chance of working out what is going on than wide shots – especially when the talent is giving their all. That same talent will want viewers to be able to read the credits. "When setting up titles, its best to put a lower third (or less) black bar, or other contrasting colour for your titles, to cover up the video and show solely your titles. That way, they won't be affected by (or affect) the video, and will often stay cleaner. In addition, make sure you use LARGE enough titles, as the screen will most likely be reduced to a 360x240 (or smaller) size. You can size down your preview window in Premiere or Final Cut Pro to that size and that will help you preview your logos and titles," advises Brown. The BMW film directors should have taken this precaution, their credits were virtually unreadable (on my 56K modem). However, separate credits were available via a hyperlink.

Bandwidth
It is worth considering how your content will be viewed (QuickTime, Real Media Player, Windows Media Player?) and at what bandwidth. "Not everyone has top notch gear. When we do put anything up we always offer it in 28K, 56K and ISDN," says Mountain. Although at the moment the BBC only uses Real. Brown points out that "corporate B2B material can usually be compressed at a much higher frames per second (FPS), size and data rate because they are usually on high-speed connections (T1 and ISDN/LAN). My take is that you should always provide two versions (high and low bandwidth) and two formats (one always being QT and then pick between WMP and RMP). I usually don't bother with WMP, as I think Real does a better job with compression."

Mountain advises to start pieces with a "fade up from black, if you can. Otherwise you go from zero to having a lot of information. A fade up will ease the information and prevent it from pixelation." For the same reason he advises: "stay away from fast editing. Think about the amount of information you are trying to process. Keep to long, still shots, three to four seconds is enough."

Brown agrees. "Dissolves and cuts are usually the best transitions to use. Digital Video Effects leave tons of artefacts from all the motion, so unless this is something you can leave at a very high data rate and FPS try to avoid them. When editing your video, remember that if you can avoid applying any effects, that will save you one compression generation on your video. But, this is often not possible, as you often want to adjust contrast, gamma, and colour to get better compression results."

Ultimately no mater what you do "connection speed is everything," says Chapman. "Over a slow connection an action movie will look horrible because it usually has so much movement. But, over a high speed line you can compress the video to keep the smooth motion in there, but the file size will be much larger. Anything without a lot of movement is perfect for the Web right now while bandwidth is still an issue. When the day comes that bandwidth flows like water there won't be any issues with movies on the Web."