The Confusing World of Digital Video
Scientists! Look no further down at us media enthusiasts.
That’s right, a lot of people believe that media isn’t complicated, but I can
tell you for sure it is. One area in particular which has complex is digital
video. Digital video is one of the key areas of media, and confuses many as
there is simply too much information for a human brain to take in. To help you
out I will be discussing this area in media, and I will be analysing websites
and other media applications such as E-mail and much more. I will be discussing
the various applications which use digital video and the technology behind it
such as the file types.
Don’t worry if you are unfamiliar with some of the
vocabulary I will use in this article to analyse the web sites, as I am now
going to explain some of the key phrases and words which would send you crazy
without any clear and detailed definitions.
So what are the different file types in digital video? There
are plenty out there and some of these are MP4 (Media Player 4), WMV, FLV, 3PG
and AVI. Each file can present different types of digital video and audio. They
are basically the formats you use to open and load a certain piece of media.
For example, the AVI format was invented by Microsoft and therefore this format
will only play some media types, believed to be because of marketing
reasons.
These numbers and letters don’t mean anything to you unless
you know what each one does, and as I analyse each web site and what kind of
digital media is used, I will explain the file format the web site and video
creators have used and in addition, I will explain why this format was chosen
over the other formats. I will try and explain every single key word or phrase
as much as I can, as it’s no good me telling you anything if it is going to fly
straight over your head! So what you waiting for…read on and find out what I
have researched into and what I want to share with you today!
So now it’s time to look at the web sites in question and
the first one two web sites I viewed was BBC iplayer and YouTube. BBC iplayer and
YouTube is the number one stop-shops for videos, which range in lengths, therefore
the video files could be quite large for the web site to handle if they are
lengthy. With this in mind, the BBC and the developers of YouTube allow the
videos to be uploaded so they could be live streamed to the user. The live
streamed videos are the programmes which were broadcasted on the BBC in the
last 7 days.
Streaming means watching video in ‘real time’, instead of
downloading a file to your computer and watching it later. With internet videos
and webcasts of live events, there is no file to download, just a continuous
stream of data. Some broadcasters prefer streaming because it’s hard for most users
to save the content and distribute it illegally. Streaming is a relatively
recent development, because your broadband connection has to run fast enough to
show the data in real time. Files encoded for streaming are often highly
compressed to use as little bandwidth as possible. It all seems good and well,
however, the audio will drop out or the screen will go blank if there is a
fault within the connection of your internet or if there’s some small minor
issue. To reduce the problem, the PC stores a ’buffer’ of data that has already
been received. If there was any problem, or if your internet couldn’t keep up with
the live stream of data, the buffer goes down for a while but the video is not
interrupted. If there is no more data in the buffer, it will usually stop and
display a message - ’buffering’ - while the stream has been caught up.
There is a variety in quality levels as some services offer
different levels of quality for different internet connections. YouTube, can
stream low, medium and high-quality videos to both mobile phone users and
broadband users. However, YouTube’s high-quality videos for phones (320 x 240
pixels) have less resolution than low-quality videos for PCs (400 x 226 pixels)
because phones have smaller screens. Most people know that downloading files
uses up their bandwidth allowance, which may be stopped at a fixed number of
gigabytes per month. But what they don’t know is how much bandwidth they use
while streaming. So watching ordinary YouTube videos can consume about 4-5
megabytes per minute. It can be more or less, depending on the quality.
One drawback with streaming is that there’s one stream per
computer - ‘uni-casting’. Broadcasters, including the BBC, would prefer to use
‘multicasting’, where everyone listens to the same stream. This would save a
lot of expensive internet bandwidth and allow better quality streams.
Multicasting is still in development.
YouTube on the other hand have all kinds of people uploading
their videos to their site, so the videos uploaded are usually streaming which
is very similar to live streaming and the way it works, other than the fact
that streaming isn’t live. People can also broadcast live streaming videos
which again, could work very well or poorly depending on how much they were
compressed and how fast your internet connection is.
As well as streaming their videos, the BBC enabled the
videos to be progressively downloaded to the user’s computer.
“Progressively
download”- This is another phrase you may not have come across before, so
what is progressive download? A
progressive download is a process that allows the user to access content before
the data transfer is complete. The user experience with a progressive download
is so similar to streaming media, that they may not notice any difference
between the two. However, with downloaded content, it is not possible to
fast-forward through any part of a file until it is stored on the user's
device. Although there is always some delay associated with playing downloaded
content, the lag may be brief enough to escape detection.
This means that the user will never see the “buffering”
message waiting to give them the go ahead with the viewing. For example, if you linked to a media file
served from an HTTP server (like BBC iPlayer), your media player will simply begin
playing it and that is a progressive download. The played file would probably
end up in your browser’s cache and it would be very easy to copy this link and
place it in another application which lets you save it. The problem with this
approach is that it becomes easy to save a file that is meant to be streamed
only. So we do not do that. Instead, a lot of companies offer streaming
solutions which do not let you easily save the file. As mentioned before,
videos from web sites such as BBC iplayer will be easily copied from computer
to computer without permission from the BBC.
Below you can see a
screen shot of the old BBC iplayer and the current BBC iPlayer. This gives you
an idea of what it used to be like for the viewers compared to today’s version.
So now you know how the videos on BBC iPlayer and YouTube are shown, you probably want to know what file formats the videos are.
So now you know how the videos on BBC iPlayer and YouTube are shown, you probably want to know what file formats the videos are.
BBC iPlayer uses Adobe Flash Player to connect the viewers
with the videos, which means the video format would be A MP4. However, before
the BBC linked with adobe, there videos were in a WMV format, but why did they
change? Firstly the difference between MP4 AND WMV is that WMV formatted videos
can only be player using Windows Media servers such as Windows Media Player”. In contrast MP4’s can be played on a much
larger scale media servers, thus makes it a lot more accessible for the user.
Another difference between these file formats is that a WMV’s get more quality from
a video within smaller files, so surely the BBC should of stuck with WMV
instead? No, because MP4
format provides a great flexibility in how data is stored in a file. However,
the problem with this that is it can create files which are not possible to
play back on a given device. Nevertheless, a layout which is not good for one
device may be very efficient for another file, so the final efficiency of MP4 formats
depends upon the usage of that format in a particular device.
Another
advantage of mp4 is that it can reference media data stored in files which are not
MP4 files. This is possible because an MP4 format references data from a URL by
file offset rather than the data structuring device of that particular file. As
a result, an MP4 format can reference data in any container format. Therefore,
this is why BBC made the right decision to change the file formats of their
videos. On the other hand what about YouTube then?
YouTube allow the users to upload many different types
of videos. Some of the well-known video formats are; MP4’s, 3GP’s, MOV’s,
AVI’s, WMV’s and FLV’s. AS you can tell YouTube allows a HUGE range of videos
formats to be uploaded to their web site, which leads to the question; how can
you tell which videos are the best on YouTube? Let’s go back to the low, medium
and high quality YouTube offer its users. Well this depends on your internet
bandwidth (like mentioned earlier) and you device. Depending on your screen
size, depends on the video quality you receive from YouTube (or any similar web
site). Let’s say you have a netbook, with a 10.1 inch screen and a 15.5 inch
laptop. The video quality on the laptop will be far greater than the quality on
the netbook.
This is all to do with the screen size and how many pixels the appliance can show. You may already know that the screen is made up of tiny pixels, but you may not know the difference between 1080P and 240P. This is basically how many pixels you see on your screen and the smaller the screen the less pixels it will be able to show, hence why its ways best to go with a bigger screen so you are able to watch higher quality videos. Another factor to consider is how strong your internet connection is. If you have a low connectivity you will struggle to view HD videos. So with these two factors considered what file format would be best to view a video on YouTube and similar web sites. Well it would be best to have a resolution of 640X360 screen size with a MPEG video format. This is because this screen size can show more pixels and this video format can be played on many servers such as QuickTime Player and Windows Media Player. It is also one of the fastest video formats in terms of downloading. It would also be best if a video was to have aspect ratio of native without letterboxing (examples: 4:3, 16:9), an audio format of MP3 with 30 frames per second, with a maximum length of 10 minutes with a file size no bigger than 1GB. This is because the longer the video the harder it’s going to be to load for the user. If a file is bigger than 1GB then it will be very difficult for the video to be uploaded as it will take a lot of time. You may have noticed the “30 frames per second” part and wondered what this meant. “Frames per second” is a measure of how much information is used to store and display motion video. Each frame is a still image and by displaying frames in quick succession creates the illusion of motion. The more frames per second, the smoother the motion appears. A typical TV show will be shown 30 frames per second, hence why it would be best for a YouTube video to be shown at this rate.
This is all to do with the screen size and how many pixels the appliance can show. You may already know that the screen is made up of tiny pixels, but you may not know the difference between 1080P and 240P. This is basically how many pixels you see on your screen and the smaller the screen the less pixels it will be able to show, hence why its ways best to go with a bigger screen so you are able to watch higher quality videos. Another factor to consider is how strong your internet connection is. If you have a low connectivity you will struggle to view HD videos. So with these two factors considered what file format would be best to view a video on YouTube and similar web sites. Well it would be best to have a resolution of 640X360 screen size with a MPEG video format. This is because this screen size can show more pixels and this video format can be played on many servers such as QuickTime Player and Windows Media Player. It is also one of the fastest video formats in terms of downloading. It would also be best if a video was to have aspect ratio of native without letterboxing (examples: 4:3, 16:9), an audio format of MP3 with 30 frames per second, with a maximum length of 10 minutes with a file size no bigger than 1GB. This is because the longer the video the harder it’s going to be to load for the user. If a file is bigger than 1GB then it will be very difficult for the video to be uploaded as it will take a lot of time. You may have noticed the “30 frames per second” part and wondered what this meant. “Frames per second” is a measure of how much information is used to store and display motion video. Each frame is a still image and by displaying frames in quick succession creates the illusion of motion. The more frames per second, the smoother the motion appears. A typical TV show will be shown 30 frames per second, hence why it would be best for a YouTube video to be shown at this rate.
YouTube in today’s media world has become a MASSIVE marketing place for all kinds of videos. You may see YouTube as a place where home users upload videos of events and unusual things that happens in their day to day lives. Whilst this may be true, there is other video which advertise and promote products or other media. From film trailers uploaded by the film producers, to product advertisement the start of some videos.
So now let’s move away from web sites and look more into
more different types of media and technology which has evolved with digital
video.
E-Mail
Those days of letters in the post are long gone now, and
today’s technology not only allows us to communicate with each other over the
web, but also allows us to attach to media files, and in particular-videos.
Whilst this may seem like a fantastic feature, it’s not as good as you may
think it is. A typical E-Mail server will only allow attachments to be no more
than 50-1000MB. This is because an E-Mail
you send has to be sent through various E-Mailing agents before it reaches the
person you want it to. These agents will save a copy of the E-mail you send,
thus there may be a maximum file size for an attachment.
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| THIS IS AN EXAMPLE OF ADDING AN ATTACHMENT TO AN E-MAIL....THIS E-MAIL ONLY ALLOWS 50MB OF SPACE PER ATTACHMENT. |
DVD’s
The storage of a DVD disc is massive compared to other e-learning technology. However the storage on a DVD disc still won’t be able to hold a full length video which has just been filmed. This is because, like any other video or media, it has to be compressed to a smaller size. To do this compression you will need to use a MPEG file format. This will allow a movie or any video to be compressed.
When a
video is placed onto a DVD disc, it is encoded in MPEG-2 format and then stored
on the disc. This compression format is a widely accepted international
standard. Your DVD player contains an MPEG-2 decoder, which can uncompressed this
data as quickly as you can watch it. Therefore you are able to watch a lengthy
video on a simple disc, great right? Well that depends on whether the data is
lossy or lossless. Lossy or lossless videos are the compressed versions of the
original filmed video. A lossy compressed video is where the original is
compressed to a really small size and makes it much easier to store on
computers and on sites, however, unfortunately there will be a significant
decrease in the quality of the video from the original- in particularly the
audio. A lossless compressed video is where the quality of the audio and the
video it’s self is not lost and is kept the same as he original. This
compression however also has a disadvantage to it. This compression will take
up a lot of room and storage space compared to a lossy compressed video. DVD
discs contain lossless compressed videos because, as mentioned, DVD discs have
an almighty storage space, but just not enough to carry the original video.
These
two types of compression are not just used in the DVD industry but used widely
through any type of digital video. User-generated content will usually be lossy
videos as the user will usually struggle to find enough space to hold a
lossless video on web sites such as YouTube. It is more likely to see lossless
compressed videos in the professional industry such as film trailers,
promotional material and general marketing/ advertising.
Below
you can see the difference between a lossy compressed video and a lossless
compressed video in terms of quality and file size. This contrast really expresses both the disadvantages and advantages of each compression type.....
On the left is a lossy compressed image which take 1.14KB of storage. On the right is a lossless compressed image which takes 9.37KB.So with that final point made, I think that’s pretty much everything I can tell you about The Confusing World of Digital Video. I recommend you remember the file formats, and the compression in particular, as this will affect the way the users view any videos you produce. I hope this has gave you a clearer understanding on this topic. Thank you for reading this article, good bye!
Good work Josh - you write in detail about the pros and cons of digital video technology. Try to be more concise so as not to detract from the point you are aiming to make.
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