Quality Control

Recently received a lecture from Mike Davidson on the subject of quality control. Below are some notes that I have taken from the lecture and from several documents linked with the subject. 

Notes on Picture Quality:

• Picture must be free of grain, excessive noise, obstructions, markings, excessive flare, lens dirt and objects of digital compression.
• Movement involved in picture must give rise to particular distortions or major changes in resolution.
• Picture must be free of unnecessary highlight compression and black crushing and visible artefacts must not be caused by hard clipping of highlights.
• Picture must be stable and continuous – no blips or jumps.
• No horizontal and vertical aliasing (i.e. jagged lines) should be noticeable.
• No digital processing that could result in visible contouring or noise.
• Picture has to be in 1080 lines, not 540 as this may cause the picture to appear odd and static.
• Picture can be in 1080i interlaced footage – Must be played in 25fps (frames per second) rate so that it can be suitable for playing on screens throughout the uni building.

This image shows the odd and even lines of a particular footage and shows how it should be processed with 1080 lines otherwise it would affect the quality.

The purpose of this image is to indicate the editors who take footage of films and cut them together and provides protection against any kind of cutting of the film.

This image is a chart that shows how our retinas respond to light, that is how our eyes pick up light and colour. I must aim to make the quality and colour of my film as good and balanced as possible.

Notes on Sound Quality

• Sound must not be recorded on severely high levels, can cause disruption and .
• Sound must recorded with efficient quality microphones appropriately placed with minimum background noise and no peak distortion.
• Stereo sound needs to be appropriately balance and free of phase differences, which could cause audible termination in mono.
• Sound peaks between -18db and -9db is suitable.
• Sound must be free of any analogue distortions and specious signals suchs as beeps, clicks, hums and noise.

Photosensitive Epilepsy:

Videos that are produce must not contain flickering or particular types of repetitive visual patterns as this may cause severe problems for viewers who have photosensitive epilepsy. Children and teenage people can be vulnerable to this.

Disclaimers and on-screen text warnings may only be used at the start of a programme in certain circumstances when the content to entirely integral and necessary to the theme of the programme and permission for said content has been cleared by the appropriate broadcaster and documented in writing.

Safe Captions

Both captions and credits in videos must be clear and legible and be positioned within the safe areas specified in the image above. For High Definition (HD) font sizes must be legible. Two primary caption safe areas are defined for material for transmission in the UK as defined in the images below.

14:9 material

4:3 material