Quality Control

We had a lecture with Mike Davidson. Here are some of the notes taken during the lecture and from the manuals sent to us. We are using this information as its important the film fits the QC specifications:


Picture Quality:

- The picture free of excessive noise, grain and digital compression artefacts.
- The picture must be free of excessive flare, reflections, lens dirt, markings and obstructions.
- Movement must give rise to distortions or break-up to moving objects, or cause large changes in resolution.
- The picture must be free of excessive black crushing and highlight compression. Hard clipping of highlights (e.g. by legalisers) must not cause visible artefacts on screen.
- There must be no noticeable horizontal or vertical aliasing, i.e. jagged lines.
- The picture must be stable and continuous - i.e. no jumps.
- There must be no visible contouring caused by digital processing. Noise must not be noticeable.
- There must be no noticeable spurious signals or artefacts e.g. streaking, ringing, smear, echoes, overshoots, moiré, hum, cross-talk etc.
- 1080 lines not 560 as it will look static and odd on the screens.
- 1080i interlaced footage - Also has to be 25 FPS to be able to be played on the big screens around uni.
- 1920 x 1080 pixels in an aspect ratio of 16:9 ␣ 25 frames per second (50 fields) interlaced - now known as 1080i/25, colour sub-sampled at a ratio of 4:2:2


- Before our video we must have a count in to with the image below counting in our video. 

This is to give indication to the editors who take the footage when they are cutting together several films and it protects against any cutting of the film!

 The image to the left shows an image of the Safe areas for  Caption. So any text or credits must be contained in the central box you run the risk of  it cutting.

Sound Info found in the manual for broadcasting specifications:

- Sound must be recorded with appropriately placed microphones, giving minimum background noise and without peak distortion.
- The audio must be free of spurious signals such as clicks, noise, hum and any analogue distortion. The audio must be reasonably continuous and smoothly mixed and edited.
- Audio levels must be appropriate to the scene portrayed and dynamic range must not be excessive. They must be suitable for the whole range of domestic listening situations.
- Stereo audio must be appropriately balanced and free from phase differences which cause audible cancellation in mono.
- The audio must not show dynamic and/or frequency response artefacts as a result of the action of noise reduction or low bit rate coding systems.

Photosensitive Epilepsy:

Flickering or intermittent lights and certain types of repetitive visual patterns can cause serious problems for viewers who are prone to photosensitive epilepsy. Children & teenagers are particularly vulnerable.

- All programmes for tape delivery must be tested using the Harding Flash Pattern Analyser v2.54b on an SD down converted SDI feed. Any failure whatsoever will result in rejection of the programme, and any affected sections must be repaired and re-tested before acceptance. Broadcasters will, at their discretion, either test the programme during the Quality Control process, or will require a relevant Harding FPA pass certificate to be delivered with the tape.
- Verbal or on-screen text warnings at start of programme may only be used in exceptional circumstances when:
The relevant content is completely integral and necessary to the context of the programme and,
Permission to use the relevant content has been cleared by the relevant broadcaster and documented in writing by those responsible for commissioning /editorial content.
Advance notification and planning requirements will vary by broadcaster.

This last post about photosensitive is important to use as we need to make sure we check with  Mike that we can have a warning at the start of our film as we need to have more than 5 flashes a second.