Media Types and Testing Flashcards
Name 2 ways of executing lossless compression with graphics
Run Length Encoding (RLE)
Lempel Ziv Welch (LZW)
Is GIF lossy or lossless?
lossless
think GIFless
Is JPEG lossy or lossless?
lossy
think JPEGy
What are the three steps of JPEG compression?
- Colour Rep changed
Resolution Reduced - Image split into 8x8 blocks
- Numeric Value scaled and stored
Name techniques of lossy compressing video data
Motion Estimation
Compensation
What are the three types of frames stored in a video?
Intra Frames (I) - Full frame (jpeg) Predicted Frames (P) - previous I frame (predicted) Bidirectional Frames (B) - interpolated from back and forward frames
Name a method of compressing audio
MPEG Layer 3 (MP3)
Is MPEG lossy or lossless?
Lossy
think MPEGy
Is FLAC lossy or lossless?
lossless
think FLACless
Is m4a lossy or lossless?
lossless
think m4aless
What is the purpose of scripting?
Increase Functionality of databases
Perform automated tasks that were previously difficult
What are the 5 steps for a web server processing PHP files
- passes HTML file to browser
- passes PHP file to PHP processor.
- browser finds tag hands file to PHP module
- Web server assumes all statements are PHP until
- Returns HTML code
How does a crawler work?
- Visits pages of your site
- Indexes the words and contents of site
- follows links from the pages
- Some focussed on particular sites
Name 7 ways to optimise code
Compressed Images Link thumbnails to full sized images Combine Images Group external CSS files Combine CSS declarations Use CSS instructions to show parts of larger images Abbreviate using hex colours
Name 5 methods to control bot indexing
Descriptive title tag Detailed meta descriptions robot.txt = cannot access meta tags to command bots noindex HTTP header
What are the 7 definitions of a usable page?
Useful Usable Desirable Valuable Accessible Findable Credible
What are 6 measures that can be taken to evaluate UX?
Successful task rate Critical/Non-critical errors Error free rate Task Times Likes/Dislikes Eye Tracking data
Name three techniques for evaluating UX
Concurrent Think aloud
Retrospective Think Aloud
Concurrent Probing
Name 4 compatibility issues
Memory Requirements
Backing Storage Reqs
Operating Sytem Version
Browser Versions
What three things should you think about with purpose of a product?
What must it do?
Who is it for?
What do they want to use the product for?
What things must designers think about in terms of user ability of a program?
Pressing multiple buttons while looking at screen
Lots of images to explain things
Ability to memorise
What are the three ability groups for target audience?
Novice
Intermediate
Expert
Name two advantages of server-side validation of forms
More secure (harder to hack) Improved compatibility
Name two disadvantages of server-side validation of forms
Can increase network traffic with more calls from servers
Responses may be slow and frustrating where bandwidth is poor
Describe 3 situations where a syntax error may occur in a database
Query incorrectly formatted
Using a formula to perform a calculation
Validation rule is incorrectly entered
Describe 5 situations where an execution error may occur when reading from a text file
Cannot locate file File has no data Read beyond the file Data in wrong order Unreadable format
State 4 ways server-side validation may be more appropriate than client-side validation
Updating centrally held data no possible with client-side
Validation can’t be disabled if handled at server
Can query SQL using PHP
Less security issues
State 3 ways code can be optimised to increase load times
CSS file to hold CSS rules = less data delivered
Merge JavaScript files = reduced fetches
Merge Images = reduced fetches
