152 lines
7.9 KiB
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152 lines
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HTML
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<a href="https://beckmeyer.us/">Joel Beckmeyer's Blog</a>
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<h1>Volatile Formats</h1>
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<div class="title-header-date">
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<time>Thursday, March 18, 2021</time>
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<p><em>Note: This is a continuation of the thoughts I started
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thinking about in my <a href="https://beckmeyer.us/posts/volatile_mediums/">Volatile Mediums</a> blog post.</em></p>
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<p>The next level up from physical mediums for data storage
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is the <em>way</em> that the data is stored. In the digital age,
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we have a plethora of formats for storing information.
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For me, one of the most interesting areas of information
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storage is the analog-digital space.</p>
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<p>The fundamental problem of storing audio, video, and other
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replications of the physical world is that there is so much
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information that we can collect with sensors
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(think microphones, video cameras, etc.). It would be great
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if we could go get the best camera and microphone out there,
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record whatever people record these days, and have that
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exact physical experience “played back” for us on a screen
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and speaker/headphones.</p>
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<p>Unfortunately, there are several problems with this. Among
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those is the actual design of the sensor. It takes a lot of
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careful thought, engineering, and the like to create a truly
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good microphone or camera. And after all of that, this sensor
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will cost something. Hopefully, that cost will correspond to
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the actual technical ability of that sensor! In any case,
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not everyone can have the best camera or microphone due to
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any number of constraints, not just those listed above.</p>
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<p>The second problem is the sampling issue. The sensor will
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create some sort of output that can then be measured, or
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<strong>sampled</strong>, by an ADC (analog-to-digital converter). The
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very word “sample” belies what this nearly magical box is
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doing: it is only looking at certain portions or timestamps
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of the analog signal. Granted, the time between samples
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can be very small (e.g. 44.1 kHz is a fairly common sample
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rate for audio), but there is still some loss of signal.
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Once the ADC creates these samples, it converts them into
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a digital format (something that can be stored on a
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CD, hard drive, thumb drive, etc.).</p>
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<p>The third problem is the encoding issue. The ADC creates all
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of these samples, but we need to start thinking about storage
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limitations. Storing the raw output of a sensor can take a
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lot of space: an average album length (40 minutes) could
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easily take 400MB of space! Now, again, the physical storage
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space is moving in the upward direction to combat this, but
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storing isn’t the only problem. One prime issue is internet
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bandwidth.</p>
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<p>The solution to this is compression, like a ZIP file. It
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makes big files smaller by doing some fancy math tricks
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that can be reversed by a computer to reconstruct the
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original file. However, for audio/video files, another level
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of compression exists which actually gets rid of some of the
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information in the original file to save more space. This
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is called “lossy” compression, as opposed to “lossless”
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compression.</p>
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<p>Great! We’ve found a way to save more space. The problem
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with lossy compression is that we have to decide which
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information to throw away. Usually, this is frequencies
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that the average human ear/eye can’t perceive. But, let’s
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just say that some compression is a bit too “greedy” when it
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comes to saving space and starts to cut into the band of
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frequencies that can be perceived. Also note that
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the design of these compression algorithms is an artform
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and takes lots of careful consideration.</p>
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<p>The final problem I want to mention is the codec problem.
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There are many different codecs available today, and for
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each and every one of them to be useful, you need to have a
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way to decode each and every one of them. Unfortunately,
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this is sometimes very difficult.</p>
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<p>It could be a licensing
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issue, where you don’t have the correct software installed
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or purchased to actually decode that file on your computer.</p>
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<p>Or it could be a physical constraints issue, where your
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computer isn’t powerful enough to decode the file at a fast
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enough rate for you to view it without stuttering,
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buffering, etc.</p>
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<p>Third, it could be a personal preference. Some people
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have much more sensitive eyes/ears and need to have formats
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that are more <strong>transparent</strong>, meaning that the lossy file
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is perceptually identical to the source it was encoded from.</p>
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<p>With all of these issues at play, I think there are several
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key points to make:</p>
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<h3 id="1-codecs-need-to-be-freely-available-for-widespread-use-with-no-strings-attached">1. Codecs need to be freely available for widespread use with no strings attached.<a href="#1-codecs-need-to-be-freely-available-for-widespread-use-with-no-strings-attached" class="heading-anchor" aria-label="Anchor"><img src="/images/chain-link.svg" class="color-adapting-image" height="20"></a></h3>
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<p>Can’t stress this one enough: we need to make sure we are
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doing everything possible to not let our information die
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when a corporation or individual makes a decision that
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impacts the “who, what, where, when, and how” of their codec
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usage.</p>
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<h3 id="2-lossless-compression-is-good-but-it-is-not-the-only-thing-we-need">2. Lossless compression is good, but it is not the only thing we need.<a href="#2-lossless-compression-is-good-but-it-is-not-the-only-thing-we-need" class="heading-anchor" aria-label="Anchor"><img src="/images/chain-link.svg" class="color-adapting-image" height="20"></a></h3>
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<p>We need to remember that not everyone has the ability to use
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lossless codecs, whether that be because of internet
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bandwidth limitations, storage limitation, or the like.
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Instead, we need to continue to innovate in the lossy
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compression space to narrow the perceptual gap between lossy
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and lossless more and more.</p>
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<h3 id="3-a-codec-should-never-become-obsolete">3. A codec should never become obsolete.<a href="#3-a-codec-should-never-become-obsolete" class="heading-anchor" aria-label="Anchor"><img src="/images/chain-link.svg" class="color-adapting-image" height="20"></a></h3>
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<p>This one may sound weird, but the fact is, if we’re talking
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about long-term storage of information, we can’t let codecs
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die, since there may come a day where we need a codec to
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decode great-grandpa’s album that never made it big.</p>
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<p>Have any questions? Let me know on <a href="https://matrix.to/#/@joel:thebeckmeyers.xyz">Matrix</a>, or start a discussion on <a href="https://social.beckmeyer.us/TinfoilSubmarine">Fediverse</a>!</p>
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