More and more, directors film their
movies with the pan-and-scan process in mind. You may notice
the next time you see a movie in the theater that most of
the shots have the important information on one side of
the screen with a lot of dead space on the other side. In
a conversation, for example, the director will show one
actor's face at a time, shooting over the other actor's
shoulder. The side of the picture showing the back of an
actor's head can be removed fairly easily so that it looks
like the movie was shot for television.
A few directors also involve themselves heavily in the formatting
process, and others are likely to follow. The late Stanley
Kubrick shot his more recent movies with both a theatrical
and a television aspect ratio in mind, and James Cameron,
who uses a special film format, creates both versions when
making his movies. The creators of the computer animated
"A Bug's Life" actually re-created a lot of the
images in the movie, moving the characters toward each other
so that most things important to the plot made it into the
full-frame video version. "A Bug's Life" is also
an interesting case because the video version was not formatted
from the film version, but taken directly from the original
digital computer images. In these cases, the video version
is still a different piece of work from the theatrical version,
but at least both works come from the same creator. The
same applies to streaming video.
Eventually, most people will actually have wider televisions,
which will make the translation from film to streaming
video much easier. Current widescreen televisions have
an aspect ratio of 16:9, which is fairly close to the
1.85:1 ratio often used for modern movies. If you watch
a 1.85:1 movie full-frame on a widescreen television,
you only lose a small amount of the picture on the sides.
If you watch it letterbox, the black bars at the top and
bottom aren't that noticeable.
But if you were to take a standard letterbox DVD and
show it on a widescreen television, the television would
have to essentially zoom in on the DVD image so that it
used the entire width of the screen. Magnifying the image
in this way doesn't provide optimal resolution, since
the DVD image is actually created for a conventional television
screen, with resolution space taken up by black bars at
the top and bottom. For this reason, DVD manufacturers
have recently developed anamorphic DVDs. Movies are stored
on anamorphic DVDs as a squeezed 1.33:1 picture, something
like the film image of a movie shot with an anamorphic
lens. When you play the DVD on a widescreen television,
the player unsqueezes it so that it fills the screen.
When you play it on a conventional television, the player
condenses it vertically and adds black bars at the top
and bottom. If it applies to video, it is also true for
streaming video and other media.
The histories of film and television have always been
intertwined, and it's a good bet they will continue to
influence each other in the future. Television images
still lag behind film images in size and resolution, but
they're getting bigger and clearer all the time, narrowing
the gap (see How HDTV Works). These advances will probably
decrease movie theater traffic, however, which may lead
to another theater presentation revolution along the lines
of the flood of widescreen movies that began in the 1950s
and '60s. If this happens, video formatters will have
to deal with a brand new group of formatting issues. There
is plenty of room on a computer screen, but formatting
for streaming video needs to follow the rules of television.
Just a couple of years ago, producing
your own short movie meant going to film school, raising
a lot of money, buying expensive equipment and looking
for distribution via film festivals.
Basically, it was out of reach for most people. Today,
with the right talent and desire, we all have a shot at
being filmmakers for 1/10th or 1/20th of the cost. A whole
new creative world has opened up, thanks to the advent
of several new consumer technologies: high-quality and
low-priced digital video, powerful desktop PCs, inexpensive
and easy-to-use video editing software and a new distribution
channel on the Web. Streaming video production can now
be done by anyone with a PC and a camera.
And as broadband DSL and cable modem access increase,
so will the audience for streaming digital video on the
Web. In addition to the Internet, numerous new devices
and appliances will be available to distribute your work.
We are already beginning to see short videos on airplanes,
in hotel lobbies, on handhelds and through interactive
TV.
To produce and showcase your own digital video involves
several key steps:
a. Shoot your video footage (use an analog or digital
video camera)
b. Capture (input video onto your Mac or PC hard drive
using a Firewire connection or video capture card)
c. Edit (use consumer-level software video editing tool)
d. Compress/Encode (use bundled video editing tool or
dedicated video compression tool)
e. Distribute (to Web, CD, DVD, etc.)
In this article, we're going to focus primarily on the
encoding and compression process with special emphasis
on encoding for the Web, which as you'll find out is a
fine art.
What is video encoding and why is it important?
First of all, digital video files are HUGE. Roughly five
minutes of uncompressed video will consume nearly one
gigabyte of space on your hard drive, and no one -
not even your adoring mother -- is going to download or
stream a video that large. So compression helps you optimize
the video while retaining the highest quality possible
for distribution on the Web.
Before compressing/encoding video for the Web, you
need to consider the following settings and criteria:
1. What Video Format/Architecture (QuickTime, Real, Windows
Media)?
2. What Data Rate?
3. What Frame Rate?
4. What Window Size?
5. Streaming Method: Progressive or Real-time?
The file compression process begins when you take your
edited video clip and encode to a particular video format
-- e.g., QuickTime, Windows Media, or Real Media -- and
compress the file size to output to either CD, DVD, or
the Web. Encoding for the Web is the trickiest part as
there are far more variables to deal with, such as constrained
bandwidth, which results in jerky, annoying videos on
the Web.
In order to encode a steady sample, it's important to
have a well-shot video source. This is why you don't see
many MTV-style videos on the web -- the transitions are
too fast, rapid camera movement doesn't compress well,
and you're likely to have jerky, delayed images, even
when compressed at a low frame rate.
Before encoding your edited video files you have to ask
yourself the following questions:
a. Which streaming method is best for my setup, progressive
(HTTP) or Real-time (RTSP) streaming?
b. What format do I want to use (Real, QuickTime, Windows
Media, or other)?
c. What is my delivery mechanism (Web, CD, DVD, etc.)?
d. If output is for the Web, what Web connections am
I targeting (56k modem, ISDN, DSL/Cable, T1)?
There are two main types of streaming: progressive streaming
(on demand) and real-time streaming (live or in real-time).
Progressive streaming takes a compressed video file and
downloads it to your hard drive via HTTP over the Internet.
Real-time streaming is usually broadcast to your browser
directly from a server. Real-time streaming uses RTSP
(real time streaming protocol) so you'll need access to
a special video streaming server.
Progressive Streaming Video
Progressive streaming is the easiest route for beginners
as it requires no special server, such as a streaming
server. You can use a standard Web server to upload your
compressed video file. Quality is generally better using
progressive streaming than with real-time. And once you
decide to play the video online, the whole file begins
to download to your hard drive. Progressive users also
can't jump ahead to other sections of the video.
Depending on the format of the streaming video (such
as Real), some progressive files may require you to download
the entire video before playing it. This creates one of
those annoying "hurry up and wait" scenarios.
Thankfully, QuickTime supports a 'fast start' feature
which automatically kick-starts your video player as it
downloads. In an age of instant gratification, this is
a great feature and QuickTime is the only major video
architecture that supports it for now. For that feature
alone, QuickTime is much better suited for progressive
streaming than RealVideo 8 or Windows Media 7.
In general, progressive streaming works best for videos
under three minutes, such as movie trailers, and the shorts
you see on sites such as Apple Quicktime TV, iFilm, Atom
Films, and on home video sites such as Share Your World.
Unlike progressive streaming, real-time streaming video
requires a special streaming server. This can be a QuickTime
Streaming Server (RTSP), a Real Networks Server or a Windows
Media Server.
Video streamed for real-time plays automatically. You
don't need to download the entire video before playing.
You can jump to any location in the video clip. And the
clip always resides on the server. Video encoded for real-time
streaming generally tries to keep pace with the user's
connection speed in order to minimize interruptions and
stalling. There's nothing you can do about general Net
congestion, but the streaming server at least tries to
compensate by maintaining a constant connection.
You'll find real-time streaming is best suited for longer
videos -- such as live event broadcasts, presentations,
training videos and lectures -- where users can skip ahead
to other parts of the clip and don't have to download
a huge video file. It also offers good protection for
your content as users can't download it to their hard
drives and redistribute your work. Unfortunately, the
video quality isn't as good with real-time as with progressive.
But getting quality video on the Web is all about trade-offs.
If you're just starting out, you might want to create
a simple Web page, encode your video using a progressive
streaming method, and embed the clip into your site. Or,
if you're determined to stream the video, you might consider
using a third party and their servers. Companies such
as Media 100 and Sorenson Broadcast Services offer a range
of encoding, hosting and streaming services.
The three main video formats on the Web are RealVideo,
Quicktime and Windows Media. When choosing a video architecture
and format, you need to evaluate current market trends
and also decide which is the best fit for you and your
audience.
Currently, RealVideo is the most popular and widespread
video format used on the Web. Real recently released version
8, but you must buy the server software to use it; the
cost after software purchase is based on connection usage.
Windows Media from Microsoft is also widespread and is
currently in version 7. Although Windows runs its own
proprietary server protocol (not the standard RTSP), it's
free and it runs on the widely available Windows Server
Platforms.
QuickTime Streaming Server from Apple, the third major
format, is based on RTSP. It's an open standard and available
on multi-platform servers from UNIX to NT. As Apache is
to Web servers, QuickTime Streaming is to video servers.
And the best part is it's free. Many professionals believe
QuickTime offers the best quality, as well as the elegant
interface that Apple products are famous for.
Streaming Video Codecs:
In order to understand video compression, you first need
to become familiar with "codecs" and how they
work. Codec stands for compression/decompression, and
it's the piece of software you use to compress very large
files, such as video or audio, into much smaller files
that can be sent out to multiple media. Normally, you
will choose a codec according to the video format you
are using.
For example, Sorenson Video 3 codec from Sorenson Media
is compatible with the QuickTime format and is the de
facto codec for QuickTime Video compression. Real Video
8 codec runs in conjunction with Real Server. The same
compatibility issues apply to audio codecs such as Qdesign
Music Pro for QuickTime. Codecs generally come bundled
with your video editing software or with compression suites
such as Media Cleaner. Every year, new and improved codecs
are released to make files even smaller, while encoding
faster and producing better quality video.
You'll probably use one of the following codecs for
video compression:
a. Sorenson Video
b. RealVideo
c. Windows Media Video
d. MPEG-1, MPEG-2, MPEG-4
e. H261/H263
f. On2
MPEG-4
Although Windows Media, Quicktime and Real Media are
the major players, an open format called MPEG-4 holds
great promise and could become the de facto video codec
standard in the same way that MP3 has become the dominant
format for music on the Web. MPEG-4 has momentum behind
for several reasons:
1. Ubiquity: Streaming video today is mostly viewed on
the Web, but the future in streaming video will be far
more prolific across multiple devices, appliances, platforms
and computers. Streaming Video will be seen in hotel lobbies,
supermarkets, airplanes, videophones, TVs and more. MPEG-4
appears to be the codec and standard for future devices
to come.
2. Unified Standard: Today, there are many codecs. The
problems that people face is sorting out which codecs
to use with which video architectures in the encoding
process. The job would be far easier for digital media
professionals if people could encode just once for all
platforms and devices.
3. Quality: MPEG-4 appears to be the most efficient encoding
standard and will encode at incredibly high-quality over
the most constrained bandwidth requirements. From what
we have seen, people will be able to have full screen
VHS quality video. Sorenson media is developing an ISO-compliant
MPEG-4 codec, as is Microsoft for use in Windows Media.
The bottom line is that MPEG-4 will be awesome in quality
and will be embedded into many new and exciting devices.
Video Encoding:
The vast majority of video content creators use Media
Cleaner Pro from Terran Interactive as their full-service
compression/encoding suite. It's an essential software
package and is widely used in the digital entertainment
industry. The Media Cleaner Pro EZ version is priced around
$250 per copy, and more often than not it comes bundled
with popular video editing tools.
Here's how a sample encoding process might go:
Once you've finished editing your video using software
such as Apple's iMovie or Final Cut Pro, Adobe's Premier,
Media100 CineStream and Cleaner EditDV or Microsoft's
Moviemaker, you save and export the edited clip to a folder
on your desktop.
In some editing suites such as EditDV or Premiere, you
can export directly from the editing tool into Media Cleaner
Pro, removing an extra step in the encoding process. Once
your clips are in a compression suite such as Media Cleaner
Pro, you're ready to prepare the clip for a particular
distribution medium. You then go through a series of check
box options, which determine the size of the clip, the
data rate, the frame rate, etc. Media Cleaner, for example,
allows you to select your video format (e.g. QuickTime),
your delivery method (e.g. Web), your data rate (e.g.
for 56k-modem), your frame rate (e.g. 10 frames per second),
and the size of your video viewing area (e.g. 240 x 180
pixels).
Read More of this fine article by Reno
Marioni
Streaming video hosting
Streaming video hosting requires a player at the audience
end.
Microsoft's Windows Media Player or Real System's G2
Player are the ideal solutions for viewing streaming media
on your intranet or internet site.
If your audience is primarily Mac-based you can also
use Quicktime.
Stream your story ...
Your video can be encoded into any or all of these formats,
depending on the needs of your target audience.
Their relative merits are discussed below.
Windows Media Player
Most users will have Windows Media Player already installed
with their Windows operating system.
It's free and it's good. It comes video ready, so just
click on a video link, sit back, and watch.
If a user with an early version of Media Player tries
to play a video stream, then Media Player may need to
download a small file called a codec first. This is quite
safe to do, and usually only takes a few seconds, before
the video will play.
IT departments can also update Media Player throughout
an organisation from a remote admin terminal, so if you
require a company-wide Media Player upgrade to the latest
Media Player 8, then this is a relatively simple procedure,
free of multi-licence costs.
Be remembered
Real Player
Real Player is the longest established video player.
Real also have a G2 Plus version which promises better
picture quality. It's available for $9.95, with discounts
on site licences.
Real Player has better sound reproduction qualities than
Media Player, so if you want to stream a music video,
or where high audio quality is crucial, then this will
probably be your best choice.
Hosting
All videos are hosted and streamed from a fast video-optimised
server.
Regular corporate servers cannot do this without an expensive
and seriously time-consuming upgrade.
If your organisation needs to stream video and wants
to minimise its bandwidth usage, then use restreaming.
This means that video is streamed in via a single external
connection to your main server.
Subsequently it is distributed internally (restreamed)
from your server.
This will reduce the number of feeds and external connections,
reducing bandwidth usage.
Restreaming can be easily set up without capital cost
for those with Win NT or Win 2000 servers, as these are
already video-ready, and contain the necessary software
to do this.
Streaming is the term used when audio or video data
is fed in a continuous stream to a PC via the internet
rather than being downloaded to the PC's hard drive. This
means that the viewer can start playing the video or audio
without waiting for the whole file to download and also
protects the content for its owner as a copy of the file
is not retained ion the viewer's hard drive.
Streaming Video Explained
The media player software on the viewer's PC decodes the
compressed stream as it arrives from the web. Leading players
include RealPlayer, Windows Media Player, Flash and QuickTime.
Streaming services are usually broken down into the following
categories:
On demand streaming: a pre-recorded file, hosted
on our servers. Typically a corporate presentation, movie
clip, music sample, demonstration of a machine or process,
etc.
Live event streaming: an event being filmed or recorded
in real time, connected to our servers from the venue and
distributed from there to the viewers. Often used for conferences,
business announcements, sporting and musical events, weddings,
etc.
Continuous streaming: this is where a playlist is
prepared before hand made up from archived files and live
events and streamed effectively as an internet TV or radio
channel