Stretch tasks R093 TA4: File Formats and Properties

Round 1: Quiz Blitz

1. SVG A vector scales with no loss.
2. JPG Use PNG when transparency is needed.
3. It pixelates or blurs It is a fixed grid of pixels.
4. WAV Record and edit in WAV, then export a compressed copy.
5. 300 72 ppi is fine on screen, but print needs about 300.
6. False Presses use CMYK. Screens use RGB.
7. The method used to encode and decode a stream H.264 and AAC are codecs. MP4 is a container.
8. 9:16 16:9 is landscape and 1:1 is square.
9. 25 fps Cinema uses 24, and sport often 50 or 60.
10. PNG; FLAC Lossless formats can be restored exactly.
11. Each JPG re-save discards more detail Lossy compression is generational.
12. Video and audio quality and file size Bit rate is the data used per second.

Round 2: Quick Fire

1. • Raster images are pixels, which blur when enlarged
   • Vector images are paths, which scale with no loss
   Model answer

   A raster image is a grid of pixels, which blurs or pixelates when enlarged, so it suits photographs. A vector image is made of mathematical paths and shapes, which scale to any size with no loss, so it suits logos.

2. • PNG supports alpha transparency, and JPG cannot
   • PNG is lossless, so text and flat colour stay sharp
   Model answer

   PNG supports full alpha transparency, which JPG cannot store at all. PNG is also lossless, so the flat colours and text in a screenshot stay sharp, with no blurry artefacts.

3. • Presses use CMYK, so the colours shift
   • 72 ppi is too low for print, so it looks pixelated
   Model answer

   Printing presses use CMYK, so RGB colours shift, and bright greens and oranges come back dull. At 72 ppi the resolution is far too low for print, which needs about 300 ppi, so the poster will look pixelated and blurry.

4. • A container, such as MP4, holds the streams
   • A codec, such as H.264, encodes and decodes a stream
   Model answer

   A container, such as MP4 or MOV, is the file format that holds the audio and video streams. A codec, such as H.264 or AAC, is the method used to encode and decode each stream, which is why two MP4 files can be completely different inside.

Round 3: Big Think

1. • The printed poster as a PDF or TIFF
   • In CMYK at 300 ppi, with bleed
   • The Instagram artwork as an RGB JPG or PNG
   • Cropped to the platform's aspect ratio, such as square
   • The logo as an SVG master, which scales
   • With PNG exports where SVG cannot be used
   • The video as an MP4 using H.264
   • Vertical, with captions
   Model answer

   The printed poster should be a PDF or TIFF in CMYK at 300 ppi, with bleed, because printing presses use CMYK and print needs high resolution. The Instagram version should be an RGB JPG cropped square at 1:1, compressed to a small size, because it is shown on screens and must load quickly. The logo needs an SVG master, because a vector scales to any size, from a badge to a banner, with PNG exports with transparency for places that cannot use SVG. The video should be an MP4 using H.264, which plays everywhere, cropped vertical at 9:16 with captions, because most viewers watch on phones with the sound off.

2. • Record and edit in WAV, which is uncompressed
   • So the masters keep full quality for editing
   • Archive as FLAC, with no loss
   • Publish as MP3 or AAC
   • A far smaller file to download or stream
   • The sounds removed are ones listeners cannot hear
   • Never re-save the MP3: edit the master and export again
   • A suitable bit rate, such as 128 kbps
   Model answer

   The studio should record and edit in WAV, which is uncompressed, so the masters keep full quality for editing. Finished masters can be archived as FLAC, which is lossless, so the files are smaller with no loss. For publishing, the episode is exported as an MP3 or AAC file at around 128 kbps, which is lossy, so the file is far smaller to download and stream, and the sounds removed are ones listeners cannot hear. Because lossy compression is generational, every change should be made to the WAV master and a new MP3 exported, never by re-saving the MP3.

This or That

1. JPG Photographs are raster images. SVG suits logos and icons.
2. SVG A vector logo scales to any size with no loss.
3. CMYK Presses print in CMYK. RGB colours shift.
4. GIF TIFF is for print production and archive masters.
5. WAV Masters are kept uncompressed for editing.
6. No: you need the dimensions Resolution is density. The dimensions give the size.
7. PDF A PDF looks identical everywhere. A PSD is a working file.
8. 24 fps Cinema uses 24 fps. 50 or 60 suits fast sport.

Memory Match

• A 6 Raster: An image made of pixels
• B 3 Vector: Paths that scale without loss
• C 1 Codec: Encodes and decodes a stream
• D 5 Container: A file such as MP4 holding the streams
• E 2 Bit rate: Data used per second
• F 4 Aspect ratio: Width compared with height

Sort It

1. Lossy JPG JPG throws away detail the eye is unlikely to notice.
2. Lossless GIF GIF is lossless, though limited to 256 colours.
3. Lossless PNG PNG keeps every pixel.
4. Uncompressed BMP A bitmap usually stores every pixel with no compression.
5. Lossless FLAC FLAC archives audio with no loss.
6. Uncompressed AIFF AIFF is uncompressed, like WAV.
7. Lossy MP3 MP3 removes sounds most people cannot hear.
8. Uncompressed WAV WAV is uncompressed.
9. Lossy AAC AAC is lossy, with better quality than MP3 at the same size.
10. Lossy MP4 (H.264) H.264 video is lossy.
11. Lossless ZIP A ZIP archive restores files exactly.