Which of the following file format is not a video file format ?
- (1).MP3
- (2).MP4
- (3).MOV
- (4).AVI
Answer
Why
Correct — option (1), .MP3.
MP3, formally MPEG-1 Audio Layer III (or MPEG-2 Audio Layer III), is an audio coding format. It was defined in 1991 as one of the audio codecs of the MPEG-1 standard, and a file with the .mp3 extension holds compressed sound, such as a music recording.
Its media type is audio/mpeg. It uses lossy compression, discarding some audio data to make files much smaller.
The other three extensions belong to container formats that hold video along with audio: .MP4 (MPEG-4 Part 14), .MOV (Apple's QuickTime File Format) and .AVI (Microsoft's Audio Video Interleave). So the one that is not a video file format is .MP3.
The idea to remember: .MP3 is an audio format; .MP4, .MOV and .AVI are video container formats.
Why the others are wrong
- (2).MP4 — MP4, formally MPEG-4 Part 14, is a digital multimedia container format most commonly used to store video and audio; it can also carry subtitles and still images.
A common combination inside it is H.264 video with AAC audio. It is derived from the ISO Base Media File Format, which is itself based on Apple's QuickTime File Format.
- (3).MOV — .mov is the extension of the QuickTime File Format, Apple's multimedia container, with the media type video/quicktime.
A QuickTime file holds one or more tracks, each storing a kind of data such as audio, video or text for subtitles, which makes it a video file format.
- (4).AVI — AVI stands for Audio Video Interleave, a multimedia container format that Microsoft introduced in November 1992 as part of its Video for Windows software.
AVI files can contain both audio and video data and play them in sync, so .AVI is a video file format.
Concept
A coding format (codec) compresses one kind of data, such as MP3 for audio or H.264 for video. A container format is a file that holds one or more encoded streams, such as video, audio and subtitles, together with the information needed to play them in sync.
An .mp3 file carries an MPEG audio stream; .mp4, .mov and .avi files are containers that can hold video.
Lossy compression, as in MP3, reduces precision and discards part of the data, aiming to still sound faithful to most listeners while making the file much smaller.
RPSC's 2023 syllabus lists "Computers, Information and Communication Technology." under Science & Technology.
MP3 was developed largely by Germany's Fraunhofer Society under Karlheinz Brandenburg. Compared with CD-quality audio, MP3 compression can commonly reduce file size by 75–95 per cent, depending on the bit rate.
That saving mattered for sharing music over the internet in the late 1990s, when bandwidth and storage were limited.
Key facts
- MP3 (MPEG-1 Audio Layer III) is a lossy audio coding format, defined in 1991 as part of the MPEG-1 standard; media type audio/mpeg.
- MP4 (MPEG-4 Part 14) is a multimedia container most commonly used to store video and audio; .mp4 is its defined extension.
- MOV is the extension of Apple's QuickTime File Format, a container of audio, video and text tracks; media type video/quicktime.
- AVI (Audio Video Interleave) is a container format introduced by Microsoft in November 1992 as part of Video for Windows.
- MP4 is derived from the ISO Base Media File Format, which is based on the structure of the QuickTime File Format.
Based on the Wikipedia articles "MP3", "MP4 file format", "QuickTime File Format" and "Audio Video Interleave".
Study next
Common traps
- Similar names, different media: MP3 is an audio format, while MP4 is a container most commonly used for video and audio.
- An MP4 file can be audio-only (it has an audio/mp4 media type too), but the format is a video-capable container; an MP3 file carries an audio stream.
- Reading AVI's name: Audio Video Interleave means audio and video interleaved in one file, so it is a video format despite starting with "Audio".
A question can list file extensions and ask which one is not a video, audio or image format.
A question can also ask what an abbreviation such as AVI or MP3 stands for, or which company introduced a format.
Related PYQs
UnlockIAS compared this question with questions from other RAS Prelims papers and found none similar enough to link.
Practice
- practice — not a real PYQ
MP3 is the common name of which coding format?
- (a)MPEG-1 Audio Layer III
- (b)MPEG-4 Part 14
- (c)Audio Video Interleave
- (d)QuickTime File Format
Answer(1) — MP3 is formally MPEG-1 (or MPEG-2) Audio Layer III. Option (2) is MP4, option (3) is AVI and option (4) is the format behind .mov files. - practice — not a real PYQ
The Audio Video Interleave (.AVI) format was introduced in 1992 by
- (a)Apple
- (b)Microsoft
- (c)Fraunhofer Society
- (d)Moving Picture Experts Group
Answer(2) — Microsoft introduced AVI in November 1992 as part of Video for Windows. Option (1) owns the QuickTime File Format (.mov), option (3) largely developed MP3, and option (4) is the group behind the MPEG standards that define MP3.