INTRODUCTION:
In today's tech savvy world, Internet, I-phones, Bluetooth, CDs, are the things that today's youth grows up and likes being around with. CD-ROMs have already started replacing text books in kindergarten and the electronic media is now the key to knowledge. All of us , at some time or the other , while working on the computer, must have come across certain highly technical terminology like a 'file format' and others such as ' VLC ' , 'AVE SQ4', 'MPEG 4 ' etc. They all may seem Greek and Latin and after being unable to complete the task sought out for on the computer, we finally become impatient and clueless. When it comes to editing a video, and the output is a single file, we all face the question "which video format should I choose?" it's a very simple question with a not so simple answer. Hence its important that we know the basics of the process of choosing a video format.
There are a lot of times when we want to put up our videos online and we are faced with the difficulty of selecting a format which is compressed without compromising on the quality. Again there are times when we want to watch videos at home on the TV, with the best quality of video and the size which can be easily accommodated in the CD/DVD. So in order to reduce the controversies, arises the need of information regarding the topic.
I choose this topic as I think that in a fast developing world like this where everything and everyone are dependent on computers for some purpose or the other, its necessary for all of us to have a computer but as well as be economical in our own way. I can't save a hundred dollars but yes, with the help of this essay I may be able to save you some of your pocket money. Today whatever we store on computers, CDs, DVDs, Pen Drives etc. requires space to be provided and trust me sometimes this space can be a lot more expensive. Many of you are fond of collecting movies either in your personal hard drives or in CDs. So lets be more pocket friendly and deal with this issue.
My research question is "Which video format balances the quality produced and the space it occupies?"
I am sure this research of mine will help you in storing your videos in the best quality with the minimum space occupied.
The conclusion of my research is that we should store all the videos/ movies/ clippings in --- format, and this will be subsequently justified and explained elaborately as we proceed.
BODY:
Now I feel its time that we find out what a video is and only then will we able to go ahead with the details of the video formats. A video is actually a three-dimensional array made of colour pixels. Two of the dimensions serve as spatial (i.e. horizontal and vertical) directions of the picture that is moving and the third dimension represents the time domain. A very interesting fact here is that the human eye is capable of distinguishing 20 images per second which means that when we are watching a video, we are actually watching a series of images which change so quickly that it misleads the eye to believe that its an animation when actually it is not! It is only the speed which gives us the illusion of animation. The succession of images, when presented at a rate of more than 20 images per second deceives our eyes. The fluidity of a video is complimented by the number of images per second (frame rate) which is expressed in fps (frames per second). Generally all the videos are also accompanied by audio effects which eventually aid in fooling our eye. A video is basically the technology of capturing, recording, processing, storing, transmitting and reconstructing a series of all still images. Video format is the media in which we save our videos. They decide the quality of the video and the space that it will occupy.
The whole concept of video formats is slightly confusing because most of the video files have at least two different types: the container and the codec which is used inside the container. The container precisely describes the file lay out - the location of the pieces, their inter leaving and the codec used by each of the piece. A video format may as well specify an audio codec with a video codec. The way in which an audio or video is encoded into a stream of bytes, is called a Codec ("coder/decoder"). It turns a raw data file into a compressed file. As the compressed files contain only some of the data that are found in the original file, a codec is a very necessary 'translator' that decides which data makes it in to the compressed version and the data which is left discarded. To make our lives even more complicated, some video formats such as mpeg-4 describes a codec as well as a container. So its not always clear as to what is being used. A movie can be encoded into an mpeg-4 codec placed in an AVI container and a movie can also be encoded into a Sorenson codec placed in an mpeg-4 container.
There are a lot of types of video formats which will be introduced to you shortly. It is necessary to know them in order to understand and conclude the research question. If you search online for the types of video formats you may be facing innumerable types but we need not discuss all of them so we will check out the commonly used ones, such as AVI , MPEG 1, MP4 , WMV...
AVI:
AVI stands for Audio Video Interleave, which is a container format. The advantage of this format is that it keeps the video quality very high and if we need to edit a video using professional software such as Windows Movie Maker or Sony Vegas, AVI is a very good choice. The drawback of this format is that it takes up a lot of space than the other such formats.
FLV:
Flash Live Video (FLV) is also a widely used format because of its innumerable advantages over the other formats. It offers a very high rate of compression making the size of video very small and at the same time produces a high quality video for putting up on the websites. It is relatively smaller in size when compared to the other formats in the same process and is also quite compatible with the browsers, namely Firefox, safari, opera and internet explorer.
3GP:
You must have come across .3gp and .3gp2 files while working with videos. It actually stands for: The 3rd Generation Partnership Project (3G/3GPP) which is a collaboration agreement. When we transfer a Video from a mobile phone to a PC, the easiest to use is the Apple's QuickTime Player. Otherwise, when we need to record a 3gp video on a mobile, it should be in accordance with the 3gp standard. Anyways mobiles also have a very limited codec support making it inefficient to play all types of 3gp2 videos.
Hence it is easier to convert a mobile video to the pc but it is not the same vice versa.
WMV
This is also a commonly used format, which stands for windows media video, developed by Microsoft. Various versions of WMV have been subsequently developed by Microsoft. The DivX format is also based on the WMV codec.
MP4:
Developed in late 1998, mp4 is a video compression standard. It is basically an extension of the earlier mpeg1 and mpeg2 algorithms with the syntheses of video and speech, artificial intelligence-based image processing techniques, computer visualisation and fractal compression.
Mpeg is basically a group under the ISO/IEC (International Organization for Standardization and the International Electrotechnical Commission) which is formulated to develop the standards for audio as well as video compression. Typically the files containing mpeg 1, 2 and 4 compressed data are supposed to have the audio and the video data streams interleaved together
Mpeg1
It is a standard which is known for encoding video and audio files at a rate of up to 1.5 megabits per second. It possesses a moderately good quality and is highly economical on space usage. The drawback, if any, of this widely used format is that it is compromising on the quality produced. VCD's generally use this format because these are usual data CDs with a pre-defined folder structure and some mpeg-1 video files in them.
Mpeg 2:
It is a better and a newer standard of mpeg1, which also supports things like high bandwidth video (a lot more than 1.5 megabits per second). Super VCD's are just like VCD's just that they use mpeg2 files and have few other features (allowing sub-titles). The ways in which VCD's use mpeg1, DVD's use mpeg2. Maximum of the digital TV systems (like Tata sky / digital cable) send mpeg 2 streams down the wire to the set top box, which eventually decodes it for us.
Mpeg 4:
It is a high compression format which has many other features. DivX, XviD are all various implementations of mpeg4.
Ever wondered how do these formats change the video quality and space that the video originally used to occupy?
Actually these formats use different strategies and approaches to squeeze the digital media files to a manageable size. Here are some of the common compression strategies used:
Psychovisual video compression
Psychovisual models discard data that are eyes don't need. An uncompressed clip that shows a chair in the same location for 60 seconds repeats the same data for that chair for each frame. With Psychovisual video compression, the data for that chair from a single frame is stored and reused in subsequent frames. This type of compression-called "statistical data redundancy"-is one of the mathematical tricks that WMV, MPEG, and other video formats use to compress video while retaining good quality.
Lossless compression
The termlosslessmeans "no loss of data." When a file is compressed in a lossless fashion, 100 percent of the data is still there, much like when you zip a document-the document file gets smaller, but all the words are still there when you unzip it. You can save lossless video over and over without any loss of data-compression simply squeezes that data into a smaller space. Lossless compression saves less space because you can compress data only so much before you have to start discarding information.
Lossy compression
Lossy compression discards data in order to achieve a lower bit rate. Psychovisual compression is a lossy technology that results in smaller files that contain less of the original source data. And every time you save your file in a lossy file format, it discards more of the data-even if you're saving it in the same format. A good rule of thumb is to move to a lossy format only as the very final step in your project.
Now that we know about the basics of video, various types of video formats and about the compression techniques, we could now probably conclude the video format which is best suited for our research question, namely, choosing a video format which is a balance between the space occupied and the quality produced. Here again lies confusion and that cant be ignored. In today's world, when there are so many kinds of portable video players being used, such as the iPod, the iTouch, portable DVD players, IRivers, etc. all of which play videos in their own specified formats which are common to some and peculiar to others. So now we need to find such formats which are compatible with maximum of these players which are so commonly used. Only out of these formats will we be able to choose one such format which will answer our research question.
While doing the research regarding this project, I examined 30 hard discs which contained a lot of movies and video clippings. I found out that AVI, WMV, MPEG2, MP4, VOB were very widely used video formats. Now my aim was to go through the specifications of the above mentioned devices, after which I concluded that Mp4, AVI and WMV were very common format used in most of the devices.
So I took a movie in the AVI format originally and converted it to Mp4 and WMV formats. I used a video formatting and joining software named "Ultra Video Joiner" version 4.7.1127 to convert the video into various formats. The table below shows the specs of the movie after converting it to these formats.
After converting the video, I compared the picture quality of all the three formats simultaneously in three different windows after pausing the video at a particular time of 20:00 minutes. By doing this I found out that Mp4 produced a better picture quality than WMV but AVI produced a slightly better quality than Mp4. Then my aim was to check for the quality of sound produced by these formats. Mp4 produced a better sound quality than WMV but the quality of sound produced by Mp4 and AVI were undistinguishable. So now I was able to dump one more video format WMV from the three chosen ones.
The last and the final task I was left out now were to compare Mp4 and AVI formats in detail so that I could conclude my research question. The comparison between these two formats is given in detail in the table underneath:
