Cambridge A Level Information Technology (ICT): Video and audio editing (9626) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover topic 11, Video and audio editing, of Cambridge International AS & A Level Information Technology (9626), following the syllabus for examination in 2025, 2026 and 2027 (version 3), sections 11.1 Video editing and 11.2 Audio editing. Topic 11 is an AS Level topic. Paper 1 (Theory) questions are based on sections 1–11 and Paper 2 (Practical) tasks on sections 8–11. Every question can be answered on paper. Calculators are not allowed in Paper 1, so the numbers work by hand.

Learn the content first in the Video and audio editing study guide and the Video and audio editing revision notes. Course hub: Cambridge A Level ICT. Checklist: 9626 checklist. Find your weak spots with a free 10-minute diagnostic.

Answers show one acceptable set of points, with a [1] per creditworthy point. This is indicative marking, not an official mark scheme; other valid points also earn credit.

Questions

1. Describe the difference between trimming a video clip and splicing video clips. [2]

2. A college posts recorded lectures on its website. Explain why captions should be added to the videos. [3]

3. A film club’s video ends with scrolling credits. The video uses two music tracks and several photographs found online. Describe how the credits should be set out. [4]

4. A square photograph, 2000 × 2000 pixels, is to be inserted into a video that is 1280 × 720 pixels (16:9).

(a) Explain why the photograph should not simply be resized to 1280 × 720. [1] (b) Calculate the size the photograph should be cropped to, keeping its full width. [2] (c) Calculate the scale factor needed to resize the cropped photograph, and show that it gives 1280 × 720. [2]

5. A 2-minute stereo recording is sampled at 20,000 Hz with a sampling resolution of 16 bits. Take 1 MB = 1,000,000 bytes.

(a) Calculate the uncompressed file size in MB. Show your working. [3] (b) State the file size if the recording is changed to mono and 8 bits, all else unchanged. [1] (c) Explain why file size depends on the sampling rate and the sampling resolution. [2]

6. A podcast is made from two interview clips recorded on different days. One clip is much quieter than the other, one shows a DC offset, and both have a steady low hum. Describe how audio editing software would be used to prepare the clips. [6]

7.

(a) Explain the difference between delay/echo and reverberation. [2] (b) Explain the difference between a high pass filter and a low pass filter. [2]

8. A school concert video is to be released on DVD, on the school website and in a version for mobile phones.

(a) Explain how the compression settings should differ for the three versions. [3] (b) Describe how lossy compression affects the quality of the video. [3]

9.

(a) Explain the difference between saving audio as a file and saving it in a container. [2] (b) An author sells an audiobook as a download. Compare WAV and MP4a as the format for the download. [4]

10. A 150-second clip of a science experiment must fit a 120-second slot in a video.

(a) Calculate the playback speed needed, as a percentage. [2] (b) Describe what could happen to the clip’s original sound and how the editor might deal with it. [2]

11. A local radio advert is made from a music track and a recorded voice.

(a) Explain why the finished advert might be changed from stereo to mono. [2] (b) Describe how the voiceover is overdubbed onto the music so the words are clear. [3]

12. A charity is making a 60-second appeal video for social media from phone footage shot in different lighting, a set of still photographs and a narrator’s recording. Evaluate the editing features and export choices the editor should use. [10]

Answers

1. Trimming removes unwanted footage from the start and/or end of a single clip [1]. Splicing joins two or more clips together end to end to make one sequence [1]. [2] Examiner insight: Two separate points are needed: describe each term; “cutting” on its own does not separate them.

2. Captions show the speech and describe other sounds [1], so deaf or hard-of-hearing students can follow the lecture [1]. They also allow watching where sound cannot be played, such as a library [1]. [3] Examiner insight: “Explain” needs reasons tied to the context; naming “accessibility” alone earns little.

3. Group the credits under headings such as cast, crew, music, images [1]. Put blank lines between the groups so each reads separately [1]. Start and end the list with blank lines so the text scrolls on and off the screen cleanly [1]. For each music track and photograph give its creator and source, such as the website it came from [1]. [4] Examiner insight: The question mentions borrowed music and photographs, so a description without source information misses the point.

4. (a) The photograph is 1:1 and the video is 16:9, so resizing to 1280 × 720 would stretch it and distort the picture [1]. (b) Height = 2000 × 9 ÷ 16 [1] = 1125, so crop to 2000 × 1125 [1]. (c) Scale factor = 1280 ÷ 2000 = 0.64 [1]; 2000 × 0.64 = 1280 and 1125 × 0.64 = 720, giving 1280 × 720 [1]. Examiner insight: In (c), show both multiplications; stating 1280 × 720 without working does not show that one factor was used both ways.

5. (a) 2 minutes = 120 s [1]. 20,000 × 16 × 2 × 120 = 76,800,000 bits [1]. ÷ 8 = 9,600,000 bytes = 9.6 MB [1]. (b) Mono halves it and 8 bits halves it again: 2.4 MB [1]. (c) The sampling rate is the number of samples taken each second and the sampling resolution is the number of bits per sample [1]. More samples, or more bits for each one, means more data must be stored for every second of sound, so the file is larger [1]. Examiner insight: Without a calculator, write each stage of the working so any slip is easy to spot and the method stays visible.

6. Import both clips as tracks [1]. Remove the DC offset to centre the waveform on zero [1] before normalising, so the level is set correctly [1]. Normalise both clips to the same peak level so the quiet clip matches the louder one [1]. Use noise reduction, learning the hum from a section with no speech, or a high pass filter, to remove the low hum [1]. Trim silences and splice the clips into one, adding a fade in and fade out [1]. [6] Examiner insight: Order matters here: saying DC offset is removed before normalising, with a reason, shows understanding rather than a list of features.

7. (a) Delay/echo produces distinct repeats of the sound after a set time, each quieter [1]. Reverberation blends many close reflections so the sound seems to be in a room or hall, without separate repeats [1]. (b) A high pass filter lets frequencies above its cut-off through and removes lower ones such as rumble [1]. A low pass filter lets frequencies below its cut-off through and removes higher ones such as hiss [1]. Examiner insight: Describe what each filter lets through; the names are easily reversed in a hurry.

8. (a) DVD: standard-definition resolution in a format DVD players accept [1]. Website: a resolution and bit rate that stream smoothly [1]. Mobile: lower resolution and a smaller file for the small screen, saving storage and data [1]. (b) Lossy compression permanently removes detail to make the file smaller [1]. Stronger compression or a lower bit rate makes artefacts visible, such as blockiness, blurring or colour banding [1], especially in fast movement such as dancers or a moving camera [1]. Examiner insight: In (b), describe what the viewer would actually see; “worse quality” alone is too vague to credit fully.

9. (a) A plain file holds one audio stream encoded one way [1]. A container is a wrapper holding one or more streams (such as audio and video) plus information about them; the codec decides the compression [1]. (b) WAV is usually uncompressed, so it keeps full quality [1], but the files are very large, slow to download and use a lot of storage [1]. MP4a usually holds AAC, so it is much smaller for good speech quality [1], although a few older players may not support it [1]. Conclusion: MP4a suits a download. Examiner insight: “Compare” needs points about both formats; a list of WAV features alone does not compare.

10. (a) Speed = 150 ÷ 120 × 100 [1] = 125% [1]. (b) Played faster, the original sound may become faster and higher in pitch, which sounds unnatural [1]. The editor could remove that audio and add music or a narration instead [1]. Examiner insight: Show the division in (a); writing 125% with no method gives no evidence if the value is wrong.

11. (a) Many radio listeners use a single speaker, and speech gains little from stereo [1]. Mono stores one channel instead of two, so the file is about half the size [1]. (b) Record or import the voice as a separate track above the music track [1]. Line it up with the music on the timeline [1]. Lower the music volume while the voice speaks, and raise it in gaps, so the words are clear [1]. Examiner insight: For (a), name the effect on size and give a reason linked to radio; “it sounds better” is not credited.

12. Indicative points:

• Trim each clip to the strongest moments so the appeal fits 60 seconds and holds attention on social media [1].
• Apply colour correction so phone shots taken in different light match [1].
• Crop and resize each photograph to the video’s aspect ratio so none is stretched [1], and add slow pan and zoom so the stills do not look static [1].
• Add the narration as an overdubbed voiceover, lowering any music under it [1].
• Add captions, because many people watch social media with the sound off [1].
• Use simple transitions and a fade at the end; too many effects distract from the message [1].
• End with a text-based slide giving how to donate, in large, high-contrast text [1].
• Export as MP4, which most social media platforms and phones play, with lossy compression keeping the file small for quick loading [1].
• Conclusion: keeping the clips short, captioned and in MP4 balances visual quality against small file size for viewers on mobile data [1]. [10] Examiner insight: “Evaluate” needs reasons and a judgement; a list of features with no link to social media or the charity’s aim reads as description only.

Where marks are usually lost

• Describing “captions” when the question wants a reason for a specific audience, or confusing captions with subtitles.
• Leaving out sources in credits when the scenario mentions borrowed music or images.
• Resizing a still image straight to the video size and ignoring the change of shape.
• Dropping the ÷ 8 or the factor of 2 for stereo in a file-size calculation.
• Writing “normalising removes noise” or “noise reduction makes it louder”.
• Listing editing features in a long answer without linking any of them to the audience or medium.

Next steps

• Revise with the Video and audio editing revision notes.
• Go back to the Video and audio editing study guide for full explanations.
• Cambridge A Level ICT hub and 9626 checklist.
• Try all free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

Cambridge International AS & A Level Information Technology 9626, syllabus for examination in 2025, 2026 and 2027, version 3, Cambridge University Press & Assessment. Topic 11: Video and audio editing (11.1 Video editing; 11.2 Audio editing).