HKDSE ICT (Multimedia) Online Practice
(Correct the answer to 2 decimal places if necessary.)
(The data in the questions are randomly generated.)
Question 1 (Modified from 2012 ICT Paper 2C Q2(b)(ii))
| Audio format | P | Q |
| Channel | Stereo | Mono |
| Sampling rate | 22.05 kHz | 22.05 kHz |
| Sample size | 16-bit | 16-bit |
If P is used, the file size is 5 MB. Estimate the file size for Q (in MB).
Answer: MB Correct!
Question 1 (Modified from 2012 ICT Paper 2C Q3(a)(i))
Peter draws a picture on a piece of paper. The piece of paper is 8×6 inches. He wants to use a scanner to scan the picture with 1200 pixels per inch and 24-bit colour. Without file compression, what is the approximate file size of the scanned image (in MB)?
Answer: MB Correct!
Question 1 (Modified from 2013 ICT Paper 2C Q1(d))
It takes Mr. Au 200 seconds to upload a 60 MB movie to the server. Estimate the transmission bit rate (in Mbps).
Answer: Mbps Correct!
Question 1 (Modified from 2013 ICT Paper 2C Q2(d))
Peter has a true-colour photo with resolution 5184×3456. Estimate the file size of the photo in MB without compression.
Answer: MB Correct!
Question 1 (Modified from 2014 ICT Paper 2C Q3(c))
Mr. Li converts the animation into a video file with the following attributes.
Frame rate: 24 frames / second
Resolution: 320×240 pixels
Colour depth: 24 bits
Bit rate: 500 kbps
Length of the video: 60 seconds
File size without compression: MB Correct!
File size with compression: MB Correct!
Mr. Li adds a 60-second sound track to the video file. The file size increases by 10 MB. The details of the sound track are given below.
Sample size: 16-bit
Channel: Stereo
Estimate the sampling rate of the sound track (in kHz).
Answer: kHz Correct!
Question 1 (Modified from 2015 ICT Paper 2C Q1(a))
Mr. Ho is the technician at ABC Secondary School. He uses a recording system to store speeches given by the Principal. The system stores audio files with the following attributes:
Sampling rate: 22.05 kHz
Sample size: 16 bits
Number of channels: 2
Data compression ratio: 10:1
Estimate the file size of a 1-minute speech in MB.
Answer: MB Correct!
Question 1 (Modified from 2015 ICT Paper 2C Q1(d)(i))
The Principal wants to upgrade the system so as to broadcast videos using streaming technology. Mr. Ho uses MPEG format for the videos at a transmission bit rate of 450 Kbps. 2 MB data needs to be downloaded before starting to play a video. Estimate the waiting time (in s) before the video can be played.
Answer: s Correct!
Question 1 (Modified from 2016 ICT Paper 2C Q1(d)(i))
The setting for Amy's video is shown below:
Frame rate: 30 frames per second
Frame size: 1920×1080
Colour depth: 10-bit
Estimate the file size of an uncompressed 20-second video (in MB).
Answer: MB Correct!
Question 1 (Modified from 2016 ICT Paper 2C Q4(c)(i))
Peter creates a 1-minute audio file as the background music of the web site. The specifications of the audio file are
Sampling rate: 44.1 kHz
Sample size: 16 bits
Number of channels: 2
Estimate the file size of the uncompressed audio file (in MB).
Answer: MB Correct!
Question 1 (Modified from 2017 ICT Paper 2C Q2(a))
The Graduation Committee in a school plans to record the collective memory of the graduates. Peter is a member of the Committee. In the graduation dinner, he will record the Principal's speech. Then he will mix it with the school song. The specifications of the recording are
Sampling rate: 44.1 kHz
Sample size: 16 bits
Number of channels: 2
Duration: 1 minute(s)
Estimate the file size of the recording in MB.
Answer: MB Correct!
Question 1 (Modified from 2017 ICT Paper 2C Q4(d)(ii))
A company has an uncompressed video about health checks. The specifications of the video are
Frame rate: 25 fps
Colour depth: 24 bits
Frame size: 1280×720
File size: 20 GB
Estimate the length of the video in seconds.
Answer: seconds Correct!
Question 1 (Modified from 2018 ICT Paper 2C Q1(b))
The specifications of a video on a web page are
Frame rate: 30 fps
Colour depth: 12 bits
Frame size: 4096×2160
Duration: 30 minutes
Estimate the file size of the video without compression in GB.
Answer: GB Correct!
Tom compresses the video and delivers it at a bit rate of 40 Mbps. Estimate the file size of the compressed video in GB.
Answer: GB Correct!
Question 1 (Modified from 2018 ICT Paper 2C Q3(b)(iii))
A web site provides audio files of weather reports with background music. The setting is as follows.
Sampling rate (kHz): 44.1
Sample size (bit): 16
Number of channels: 2
Peter keeps the uncompressed audio files for editing and each file is limited to 20 MB. What is the maximum length (in s) a weather report could be?
Answer: s Correct!
Question 1 (Modified from 2019 ICT Paper 2C Q1(d))
Peter broadcasts his live performance using streaming technology. The sepcifications are:
| Audio | Video |
| Sampling rate: 44.1 kHz | Frame rate: 24 fps |
| Sample size: 16 bits | Frame size: 1920×1080 |
| Channel: Stereo | Colour depth: 24 bits |
Assume that the bit rate is 4 Mbps after encoding and at least 2 MB data have to be downloaded before the streamed video starts to play.
Estimate the number of frames to be downloaded before the streamed video starts to play.
Answer: Correct!
Estimate the file size required for a 1-second performance without compression in MB.
Answer: MB Correct!
Estimate the data compression ratio required for the broadcast.
Answer: :1 Correct!