A real-time video of a music concert needs to be streamed to subscribers. Tick (✔) one box to identify the most appropriate type of compression and justify your answer. Lossy Lossless Justification

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2023). The mark or mark type is shown in brackets.

1. [3] (a) Lossy compression (ticked) Loss of quality will not be noticed Needs to be viewed in real time so less bandwidth needed if file size smaller Smaller file sizes will reduce buffering so the video will play more smoothly Viewers may watch on different devices, so may not need high quality resolution OR Lossless compression (ticked) Original recording may not have been made in high resolution Could be streaming to high bandwidth devices The reduction in the file size is sufficient for the receiving device Viewers do not want any loss of quality
2. [3] (b) Increase sampling resolution: The number of bits used for each sample is increased. There will be more values available to represent each sample // more amplitudes can be represented. Each binary amplitude/note in the digital recording is closer to the analogue amplitude/note. Quantisation errors are reduced. The digital soundwave is closer to the original analogue soundwave. OR Decrease sampling resolution: The number of bits used for each sample is decreased. There will be fewer values available to represent each sample // fewer amplitudes can be stored. Each binary amplitude/note in the digital recording is further from the analogue amplitude/note. Quantisation errors are increased. The digital soundwave is less like the original analogue soundwave.
3. [2] (c) 1 mark for answer, 1 mark for working Answer: 2.5 mebibytes Working: (2048 × 1024 × 10) / (8 × 1024 × 1024)