Compression

I’m starting to realise that I’m having trouble with this blog lately because we’re focusing on technical aspects now and even though I have read a lot, I can count the amount of technical literature I have read on the fingers of one hand. Basically, my problem is that I don’t know how to talk about our topics anymore. I like using metaphors and alliterations and repetition but using literary stylistic devices in a technical writing feels inappropriate to me somehow. Consider this both an exclaimer and an explanation. It doesn’t mean I’m not putting in effort anymore, if anything I spend more time on blog posts now, but it feels less easy-going than it used to.


Although often considered one and the same, file format and video format differentiate from each other. The file format is frequently described as a container that contains the actual video. Different media players are dependent on the kind of box they receive, some like the VLC player have the ability to “open” most, if not all of the boxes. Other players, like Quick Time only accept certain packages. Basically, the file format decides which type of player will be able to understand and play the file. Video format, on the other hand, does not solely decide the type of player that will be able to understand and play the video, but it also determines the quality of the video. Video quality can be separated into colour and luminosity.

Furthermore, the video format, often called video codec, compresses and decompresses data. In the box metaphor, it would take the place of the product inside. In class we used the explanation that the video format is the “flavour of compression that is used on the video”.

Examples for file format are H.264, .mov, .flv, .jpeg, .tiff

Examples for video format are Animation, MPEG4, Apple Process, H.264

The reason why the format is so important and needs to be considered is that there is no one format that works on everything.  So before we start to compress, we need to determine the platform we want to present the video on and choose appropriate formats accordingly.

Video formats are also differentiated into lossless and lossy codec. The lossless codec doesn’t lose any of the quality while the other one reduces the file size. This is dependent on the bit rate and the resolution.


Finally, the task was to apply four different types of compression on one video.

The videos are ordered by ascending quality. So, the first video has a 3GPP file format and MPEG-4, AAC as video format. 05/10 is a Quick Time file with Apple Intermediate Codec, Linear PCM, Timecode video format. (Unfortunately, YouTube doesn’t upload videos in this format so I added the dropbox-link to the upload.) The third video is inside of a MPEG(2) box and has a MPEG-2, MPEG Layer 2 video format. Finally, the original file is a MPEG-4 movie and has a AAC, H.264 codec.

(Not entirely sure if this is how you talk about video and file format but you should be able to understand what I mean.)

info

It is also quite interesting that the different video formats had a descending resolution along with the decreasing quality as seen on the picture below.

videos



Video with 05/10 quality



Cheers.

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