シャドーイング練習: Every Major Image Format Explained in 8 Minutes - 動画で英語スピーキングを学ぶ
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JPEG.
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JPEG or JPG is the most widely used image format in the world, and it's the default format your phone camera saves photos in.
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And as so you know, JPEG and JPG are actually the exact same thing.
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The reason you sometimes see JPG instead of JPEG is because older Windows systems could only handle three -letter file extensions.
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Therefore, the letter E was excluded.
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Anyway, back before jpeg existed image files were so massive that sending
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or storing photos was a nightmare especially with the slow limited
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storage of early computers that's why jpeg was created using lossy compression
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that permanently throws away some of the image data your eyes
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barely notice anyway just to shrink the file size down this is great for storage
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and sharing since a jpeg can be a fraction of the size of the original image
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but because jpeg throws away data permanently it's not ideal for editing
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or zooming in since it becomes pixelated or blurry the moment you scale it up too much.
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That's because JPEG is a raster image, and in case you don't know, image files actually come in two major types, raster and vector.
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Raster images, like JPEG, are built out of a fixed grid of pixels, which means they lose quality and look blocky the moment you zoom in too far.
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Vector images, on the other hand, are built from lines and curves defined by math instead of pixels
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so they stay perfectly sharp no matter how big you scale them up
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which is why logos and icons are often made as vector files instead also saving
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and resaving a jpeg multiple times like after repeated edits keeps degrading the quality a little more each time
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but despite that jpeg remains the go -to for photographers social media
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and basically anyone who just needs a decent looking photo without
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the file size ballooning png png short for portable network graphics
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was created to fix the one thing jpeg could never do
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well keeping an image perfectly sharp without losing quality no matter how many times you save it
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so unlike jpeg's lossy compression png uses lossless compression instead
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which means it shrinks the file size without throwing away any of the original data.
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And on top of that, PNG also supports transparency, which lets you make part of an image completely invisible, which is why logos, icons,
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and layered designs are almost always saved as PNG.
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But because PNG doesn't throw anything away, the file sizes end up much bigger than a JPEG of the same image, especially for photos with a lot of detail and color variation.
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That's why PNG isn't really used for photography, but it's still the standard for screenshots, graphics and anything
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that needs a transparent background gif gif short for graphics interchange
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format is the format everyone recognizes for short looping animations
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and it's used everywhere from memes to reaction clips
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so the way gif pulls off animation is by storing multiple image frames inside one single file
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and then displaying them one after another in a loop
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but despite being
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so widely used gif has one major limitation it can only
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display 256 colors at once this is why gifs often look grainy
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or slightly off color compared to the original video they were
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made from since a lot of color detail simply gets lost
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in the process webp webp is a format created by google specifically to make websites load faster
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and it's slowly replacing both jpeg and png on modern sites.
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So the way WebP achieves this is by combining JPEG's small file size with PNG's transparency support, all in one format.
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This means a website can use a single format for both photos and transparent graphics instead of juggling two different ones.
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And because WebP compresses more efficiently than JPEG, images can be up to 30 % smaller at a similar quality level,
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which is a big deal for how fast a page loads on your phone.
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But despite all these advantages, Not every app, program, or older device fully supports WebP yet,
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which is why some people still convert WebP images back to JPEG
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or PNG just to make sure they'll open everywhere without issues.
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TIFF.
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TIFF, or T -I -F, short for Tagged Image File Format, is a format built specifically for professionals in printing,
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publishing, and photography who need the absolute highest image quality possible.
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So just like PNG, TIFF supports lossless compression, but it goes even further by supporting multiple layers,
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high color depth, and even multiple pages inside a single file.
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This is why TIFF is the standard format for scanned documents and print -ready photography, since printing companies need every tiny detail preserved with zero compression artifacts.
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But remember, because it stores so much data, TIFF files can get enormous, sometimes hundreds of megabytes for just one high -resolution image.
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And not only that, TIFF also isn't well supported by web browsers, so you'll basically never see a TIFF file used on a website.
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That's why, despite being the gold standard for print quality, Most people convert their TIFF files to JPEG or PNG the moment they need to share them online.
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The BMP or Bitmap is one of the oldest image formats still around, and it's been built into Windows since the very early days of the operating system.
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So the way BMP works is it stores every single pixel's color information directly with basically no compression at all.
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This is why BMP images look perfectly sharp with zero quality loss, but it also means the file sizes are massive,
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sometimes several times bigger than the exact same image saved as a JPEG or PNG.
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Because of this, BMP isn't really practical for sharing images online or storing large photo libraries,
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but it's still occasionally used in situations where speed matters more than file size, like certain image processing software,
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since the computer doesn't have to spend time decompressing anything before it can read the pixels.
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Other than that, though, most people today have basically no reason to use BMP anymore.
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H -E -I -F and H -E -I -C.
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H -E -I -C, short for High Efficiency Image Container, is the format Apple made the default for photos on iPhones.
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So the reason Apple switched to this was because JPEG, despite being everywhere, hadn't really improved in decades, while phone cameras were producing bigger and bigger photos every year.
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H -E -I -C solves this by using a much more advanced compression method the same one used in video
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which lets it store a photo at roughly half the file
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size of a jpeg with basically the same quality not only
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that hiec can also store multiple images
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or a live photos motion frames inside a single file but
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because it's still fairly new outside the apple ecosystem heic isn't well supported on windows
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or many websites avif avif is the newest image format on this list
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and it's built on the same av1 video technology
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that platforms like youtube use to stream video more efficiently
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so just like heic avif can compress images down to a fraction of a jpeg size
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while keeping the same visual quality but the difference is avif is completely open
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and royalty free
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which means any company can use it without paying licensing fees
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this is why avif is quickly becoming the preferred format for major websites since smaller images mean faster loading pages.
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However, encoding and decoding AVIF images takes more processing power compared to older formats,
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and just like HEIC, not every app or image viewer supports it yet, so you'll sometimes run into an AVIF file that simply won't open.
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But as more browsers and devices catch up, AVIF is expected to slowly become the standard, especially for the web.
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Oh yeah, JFIF, which stands for jpeg file interchange format isn't really a separate
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image format on its own it's more like a wrapper
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that defines exactly how a jpeg file should be structured
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so the way this works is jfif locks down details
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that regular jpeg left undefined like resolution aspect ratio and color space
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so a jpeg saved on one program looks the same
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when it's opened on a completely different device this is why
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technically almost every jpg file you've ever opened is actually a jfif file underneath you might have noticed this yourself
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if you've ever right clicked
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and saved an image from chrome since sometimes it saves as .jff instead of .jpg
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because chrome is technically labeling the file by what's actually inside it
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but despite being the exact same compression jfif can cause small compatibility headaches since some upload forms
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or older programs only look for a .jpg or .jpeg extension and reject a .jfif file even though it's identical data.
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So yeah, if that happens, you can literally just rename the extension and it'll work fine.
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この動画でスピーキング練習する理由
画像形式について説明するこの動画は、日常的な説明的スピーキングの練習に最適です。話者は「JPEGは世界で最も広く使われている」「PNGは透明性をサポートする」など、明確な情報を簡潔に伝える表現を使っています。shadowing siteやshadowspeakを使って繰り返し練習することで、情報を整理して伝える能力が向上し、英語スピーキング練習に欠かせない流れの良い発音やリズムを身につけることができます。
文脈の中の文法と表現
- 「〜の理由は〜です」の表現：「The reason you sometimes see JPG instead of JPEG is because...」は、理由を説明する際の典型的な構造です。日本語の「〜の理由は〜です」に相当し、会話でも頻繁に使われます。
- 対比表現「on the other hand」：「Vector images, on the other hand, are built from lines...」は、二つのものを対比するときに使われるフレーズです。「一方で」と訳され、議論や説明で大切な役割を果たします。
- 「〜にもかかわらず」の表現「despite that」：「but despite that jpeg remains the go -to...」は、前文のデメリットを認めながらも結論を述べる場合に使われます。「それにもかかわらず」というニュアンスで、話の流れをスムーズに進めます。
発音の注意点
この動画にはいくつか発音が難しい単語があります。例えば「compression」（圧縮）は「コンプレッション」と発音しますが、「ssion」の部分が曖昧になりがちです。また「raster」（ラスター）は「ラスター」と発音し、「vector」（ベクター）は「ベクター」です。shadow speakをする際は、これらの単語の発音を注意深く聴き、正確に真似ることが重要です。さらに「transparency」（透明性）は「トランスペアレンシー」と発音し、語尾の「cy」をはっきりと発音することで、より自然な印象を与えます。
これらのポイントに注意しながらshadowspeaksを使って練習すると、英語のスピーキング能力が効率的に向上します。ぜひこの動画を使って、shadowingの練習を始めてみてください。
この動画の文法
話し手がよく使っている文型を、動画の実際の表現とともに紹介します。
| 文型 | 動画での表現 |
|---|---|
| 受動態 be + 過去分詞 — 誰がするかより、何が起きるかに焦点を当てる | was excluded · was created · are built |
| 関係詞節 who / which + 節 — 人や物について情報を加える | pixels, which means · anyone who just · invisible, which is |
シャドーイングとは？英語上達に効果的な理由
シャドーイング（Shadowing）は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的：ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影（shadow）」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。