Media Compression

 This week we were asked to watch 5 videos about media compression.


The first video described the differences between spatial (intraframe) and temporal (interframe) compression. Intraframe compression only works on individual frames of a video. It breaks the image down into a .jpeg format, making the image smaller. Sometimes, large blocks of pixels can be left behind during the compression process, this is called “compression artefacts” Interframe compression works in an .mpeg format by removing “redundant” information, these are pixels that don't change from one frame to the next. The example used in the video is the large white void edited in behind the speaker. The video also explains that a higher bitrate will result in a higher quality video, while a lower bitrate will give a lower quality video, regardless of compression.


The second video we watched showed the difference in the same video with reduced frame rates. The 60 frames per second (FPS) video looks smooth and satisfying, even in slow motion. You can’t really notice any lag or delay. The 30 FPS video looks nearly the exact same, there isn’t any difference to the naked eye. The 15 FPS video is noticeably different. You can tell that there’s frames missing, especially in slow motion shots. The video looks as if it’s lagging or struggling to keep up with the monitor. The 8 FPS video looks very poor. The video is choppy and smaller details are harder to keep track of. While 60 FPS is theoretically the best option, 30 FPS works just as well, and would eliminate half of the data in a single video.


The third video we watched discussed what information is lost during audio compression. When audio is compressed into a high quality .MP3 format, it’s really hard to tell the difference between the compressed and uncompressed audio. The video shows how to find out what audio is lost from the track when compressed, and as it turns out you do lose a small bit of drums from the song used in the video. When the audio was compressed into a low quality MP3 format, we lost a lot more information. The song sounded a bit more flat and thinner than the original file. When we’re shown what information was lost, you could clearly hear vocals and musical flourishes that were lost. 


The fourth video we watched discussed different video formats, codecs and containers. I found the video very hard to follow, since there was so much information being present so quickly, however I do feel more informed on what formats and codecs to use when completing my project, and other projects I’ll work on all throughout this course. 


The fifth video we watched explained what bits are. Bits are each individual 1s and 0s that can store information on a device. 8 bits are 1 byte. 1 byte is enough storage for a single letter in a text document. 1,000 bytes makes up one kilobyte (kB), however there are actually 1,024 bytes in a kB due to the binary system using the power of 2. One kB can hold a third of a page of text. 1,000 kilobytes makes one megabyte (MB), this is enough to approximately store a book, a photo or a minute of music. ,1000 megabytes is 1 gigabyte (GB), which can hold up to 16 hours of music. 1,000 gigabytes makes 1 terabyte (TB), this is enough to hold 2 years worth of music.


I already knew quite a bit about media compression, having worked a lot with video and image in the past. However, I now feel a lot more informed on how to correctly compress media and what formats and codecs to use.


Image by ShariJo from Pixabay



Reference list:

“Video Compression as Fast As Possible” by Techquickie: https://www.youtube.com/watch?v=qbGQBT2Vwvc

“Difference in Framerates | 60FPS vs 30FPS vs15FPS vs 8FPS (Full HD)” by Typical Gamer Moments: https://www.youtube.com/watch?v=2Ds7EcJ2Ia4

“What You Lose When You Compress Music to MP3, M4A, WMA, etc.” by Double A: https://www.youtube.com/watch?v=MmecPiKClHk

“Video Formats, Codecs and Containers (Explained)” by Qencode: https://www.youtube.com/watch?v=XvoW-bwIeyY

“Computer Skills Course: Bits, Bytes, Kilobytes, Megabytes, Gigabytes, Terabytes (UPDATED VERSION)” by Dane Hartman: https://www.youtube.com/watch?v=u4P0LOofEFs


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