問86
頻出度★☆☆
イラストなどに使われている, 最大表示色が256色である静止画圧縮のファイル形式はどれか。
平成30年度 秋期 ITパスポート試験 問86
テクノロジ系情報メディア › マルチメディア技術
This question's explanation and your answers so far.
解説
問 86
- ア
正解 The correct answer is “ア”, GIF. GIF (Graphics Interchange Format) uses an 8-bit color palette, so its maximum number of displayable colors is limited to 256; it is a still-image file format that uses lossless compression. It is well suited to representing logos, icons, illustrations, and simple graphics that use few colors, and it satisfies all three conditions in the stem: “used for illustrations and the like”, “a maximum of 256 displayable colors”, and “still-image compression”. Therefore GIF is the correct answer.
Incorrectイ
JPEG is a still-image compression format that can handle full color (about 16.77 million colors); it uses lossy compression and is suited to images with rich gradation such as photographs. Because its displayable colors are not limited to 256, it does not meet the condition of “a maximum of 256 displayable colors”, so it is wrong.
Incorrectウ
MIDI is a data format for music (audio) that exchanges the performance information of electronic musical instruments (pitch, duration, velocity, etc.); it is not a still-image file format, so it is wrong.
Incorrectエ
MPEG is a format for compressing video (moving images and audio); its target is video rather than still images, so it is wrong.
ここがポイント
- GIF is a lossless-compression still-image format with up to 256 colors (an 8-bit palette), suited to images with few colors such as illustrations and icons.
- Distinguish the formats for images, audio, and video: still image = GIF/JPEG (JPEG is lossy and aimed at full-color photos), video = MPEG, music = MIDI.
用語