The document provides an overview of video codecs and container formats, explaining their importance in video playback and distribution. It covers the evolution of video standards from the 1950s to the digital era, the differences between frame-based and temporal codecs, and considerations for screen resolution and frame rates. It also highlights the challenges in video production and playback due to the multitude of formats and compression options available.

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3.  What is a Codec?
 What is a Container Format?
 Temporal vs Frame Based Codecs
 Screen Resolution
 Frame Rates
 Workflow
 …and then, at the end, making sense of it all!

4.  Why will your PC play some video files and not
others? It’s all down to codecs
 So why do we need codecs?

5.  Video takes a lot of storage space on your
PC/Mac
 For instance 3 minutes of captured Full HD
camcorder footage uses about 1gb of storage
 On the plus side,
storage is now cheap

6.  The trouble really comes when trying to distribute
the footage
 People don’t want to be given hard drives to plug
in to their TVs. They want DVDs, iPod videos,
Sky+, Freeview & YouView
 So the files need converting to suit these media

8. ...the trouble is that there are hundreds
(thousands?) of compression options!
 But let’s start at in the 1950s...

9.  Way back in the 1950s three main broadcast
standards were established by various countries:
 PAL (in the UK)
 NTSC (in the USA)
 SECAM (in France)

10.  ...and they all worked quite happily for the next
thirty years!
 This was mainly because video production was
expensive and made by a small number of
companies. Thus easily regulated.
 Then in the 1990s
came digital!

11.  The Digital Revolution of the 1990s made video
production cheap and available to the masses.
 This made it difficult (impossible?) to regulate.
 New digital ‘standards’ were required, and lots of
options competed...

12.  Instead of being imposed like the 1950 standards,
the new standards were in competition with each
other
 The theory was that the best standard(s) would
become dominant
 The actual result was a minefield of formats,
containers and codecs...

13.  Codec stands for Code / Decode
 It is basically a computer program that en-codes
video to a specified format
 From this point on the same codec is needed to
play (decode) the video

15.  The trouble comes when you move your video to
another computer...
 ...if that PC/Mac hasn’t got the required codec
installed (to decode the video) then your video
won’t play.
Tip: PC users can try ‘G-Spot’ (freeware) to
identify the codecs used by a video

16.  Sorenson 3
 H.264
 Cinepak
 Oh, and there’s an another pile of codecs for
encoding audio files!
...eh, what about Quicktime and AVI?

17.  Here’s the big confusion: Quicktime, AVI and
Flash Video are not codecs!
 These are ‘container’ formats.
 This basically means that they contain codec
compressed video and audio in one easy to play
file.

19. Video codecs can be broadly split into two types:
 Frame-based codecs
 Temporal (or field-based) codecs.

20. Video codecs can be broadly split into two types:
 Frame-based codecs
 Temporal (or field-based) codecs.
 Say What!?!

21.  Well known examples are Cinepak
and Motion-JPEG
 They work by examining and compressing each
frame of video individually
They have two main disadvantages:
 They can be slow to encode
 File sizes can be quite large

22. =
Time

23.  The best known is MPEG-2 (used for Digital TV &
DVDs)
 They watch how much a video clip changes from
frame to frame then compress only the changes
between the first full frame (a keyframe) and the
following frames.
 Thus keeping file sizes down!

24. =
+
+
+
Keyframe

25. +
+
+
=
Copies unchanged parts
of the keyframe

26.  The quick answer to this question is to use the
relevant presets within your editing software:

27.  But it’s always worth checking with your client
about their requirements.
Especially if they’re planning on showing the video
overseas.
 This is where programs like Apple’s Compressor
come into play (but that’s another presentation for
another day!)

28. ...no, it’s not over yet!

29.  So we know about codecs, container formats, and
how they encode video & audio files...
 ...but we still need to mention Screen Resolution
(or how big the screen is)

30.  All TV and DVDs in the UK used to use the same
Screen Resolution: 768 x 576:
768 pixels
576 pixels

31.  Digital Video (from about 1995) reduced this to
720 pixels which were then ‘stretched’ to cover the
‘missing’ 48 pixels:
576 pixels

32.  It doesn't matter if you watch TV on a 12” portable
or fill a wall with a video projector – you don’t get
any more pixels!

33.  All this was true until the
arrival of High Definition
...but guess what...
...there’s competing formats (again)!

34.  HD Ready means that the screen resolution is:
1280 x 720 pixels

35.  HD Ready means that the screen resolution is:
1280 x 720 pixels
Notice the change in shape – this is
called Aspect Ratio

36.  HD Ready means that the screen resolution is:
1920 x 1080 pixels

38.  What this means is:
 Photos used in videos must be at least the size of
the video resolution used

39.  Or this happens:

40.  Minimum of 3 megapixels

41. Not big enough for HD!

42. HD needs 1920 x 1080

44.  Each frame is made from two images spliced
together:
- Tends to be used by tape based cameras
- Good for fast moving action (sports)

45.  Each frame is a single image:
- Looks more cinematic and classy

46. Interlaced Video displays 50 half-frames (or fields) every second.
It shuffles these in alternate rows, this tricks the eye but can look
messy when paused or printed out
Note:
Horizontal
Banding

47. 1080i 1080p

50.  Traditionally 24 fps

51.  30 fps
 (actually 29.97 fps!)

52.  25 fps

53.  50 fps (ideally)

54. - That’s the complex stuff done!

56. 1080i/50fps1080i/50fps 1080i/50fps1080i/50fps 1080i/50fps1080i/50fps

57. 1080i/50fps1080i/50fps
720p/50fps720p/50fps 1080p/50fps1080p/50fps

58. 1080p/60fps1080p/60fps 1080p/50fps1080p/50fps 1080p/50fps1080p/50fps

59. 640p/15f
ps
640p/15f
ps
1080p/50fps1080p/50fps 1080p/50fps1080p/50fps

60. 720p/25fp
s
720p/25fp
s
1080p/50fps1080p/50fps 720p/25fp
s
720p/25fp
s

61. 1080p/25fps1080p/25fps 1080p/25fps1080p/25fps 1080p/25fps1080p/25fps

62. 1080p/25fps1080p/25fps 1080p/25fps1080p/25fps 1080p/25fps1080p/25fps

63. 1080p/50fps1080p/50fps
Adobe Media Encoder /
Apple Compressor
Adobe Media Encoder /
Apple Compressor

64.  Adobe Premiere will take care of this for you…

65.  VideoPad does a similar thing…

66.  Follow the Adobe Premiere handout
 If Premiere is slow or exporting is taking an age,
it’s probably due to bad workflow

67. ---End---