Consider the following : 1. MPEG 2. P*64 3. Indeo Which of the above can be used to compress video files ?
- (a)1 and 2 only
- (b)1 and 3 only
- (c)2 and 3 only
- (d)1, 2 and 3
Correct — D, 1, 2 and 3. All three names on the list compress moving pictures. MPEG is the family of standards from the Moving Picture Experts Group — MPEG-1 for Video CD, MPEG-2 for DVD and digital television, MPEG-4 for streaming. P*64, read as p times 64, is the ITU-T H.261 family designed for videoconferencing over ISDN lines whose bandwidth comes in multiples of 64 kilobits per second, which is where the name comes from. Indeo was Intel's video codec, shipped for desktop video on Windows through the 1990s. Since none of the three can be struck off, the answer takes in all of them.
- (a)1 and 2 only — This drops Indeo. Indeo Video was a genuine codec developed by Intel and licensed widely for desktop playback; it compresses video, so it cannot be excluded.
- (b)1 and 3 only — This drops P*64. The p times 64 scheme is the ITU-T H.261 videoconferencing standard, the first practical digital video compression standard to be widely deployed.
- (c)2 and 3 only — This drops MPEG, the best known video compression family of all. MPEG-2 alone carries DVD and most digital broadcast television.
Video compression removes two kinds of redundancy. Spatial redundancy within one frame is cut by a transform and quantisation, much as JPEG does for a still picture. Temporal redundancy between successive frames is cut by motion compensation, where the encoder stores only the difference from a predicted frame. MPEG, the ITU-T H series and proprietary codecs such as Indeo all build on that same pair of ideas and differ in how far they push each one.
The printed stem says P*64, and that is what the booklet shows. Read it as p x 64 kilobits per second, the ITU-T H.261 videoconferencing family for ISDN, not as H.264. H.264 (also called AVC, standardised in 2003) is a later and quite different codec, and a data set that quietly modernises the printed name changes what the candidate was asked to judge. Both are real video standards, so the answer is the same either way, but the wording is not. The item is a straight recall check: if even one of the three names is unfamiliar, the safe move is to ask whether it belongs to video at all, since none of these is an audio or image-only format.
- MPEG stands for Moving Picture Experts Group; MPEG-1, MPEG-2 and MPEG-4 are all video compression standards.
- P*64 is the ITU-T H.261 family, built for videoconferencing over ISDN channels of 64 kilobits per second each.
- Indeo Video was Intel's codec for desktop video on personal computers in the 1990s.
- H.264, also known as AVC, is a separate and later standard from 2003 — it is not the same thing as P*64.
- JPEG compresses single images; MP3 compresses audio. Neither belongs to a video-only list.
All three printed items compress video, so the code that takes in every one of them is the answer.
- Reading P*64 as H.264 and answering a different question from the one printed.
- Assuming an unfamiliar name such as Indeo must be the odd one out.
- Mixing up a container format such as AVI with the codec that fills it.
A three-item 'consider the following' where all three belong, so the examiner is really checking whether an unfamiliar name tempts you into excluding it.
No directly related past PYQ was found.
- practice — not a real PYQ
MPEG is a family of standards used mainly for which one of the following?
- (a)Compressing video and audio
- (b)Encrypting email
- (c)Indexing databases
- (d)Routing network packets
Answer(a) Compressing video and audio — the acronym expands to Moving Picture Experts Group.
- practice — not a real PYQ
Which one of the following compresses still images rather than moving pictures?
- (a)MPEG-2
- (b)JPEG
- (c)H.261
- (d)Indeo
Answer(b) JPEG — the Joint Photographic Experts Group standard for single images.