 Why will your PC play some video files and not
others? It’s all down to codecs.
 So why do we need codecs?
 Video uses a lot of storage space on your
PC/Mac.
 For instance 5 minutes of captured camcorder
footage uses about 1gb ...
 The trouble really comes when trying to distribute
the footage.
 People don’t want to be given hard drives to plug
in t...
...the trouble is that there are hundreds
(thousands?) of compression options!
 So let’s start at the top...
 Way back in the 1950s three main broadcast
standards were established by various countries:
 PAL (in the UK)
 NTSC (in...
 ...and they all worked quite happily for the next
thirty years!
 This was mainly because video production was
expensive...
 The Digital Revolution of the 1990s made video
production cheap and available to the masses.
 This made it difficult (i...
 Instead of being imposed like the 1950 standards,
the new standards were placed in competition with
each other.
 The th...
 Codec stands for Code / Decode
 It is basically a computer program that en-codes
video to a specified format
 From thi...
 The trouble comes when you move your video to
another computer...
 ...if that PC/Mac hasn’t got the required codec
inst...
 Sorenson
 Indeo
 Cinepak
 Oh, and there’s an another pile of codecs for
encoding audio files!
...eh, what about Quick...
 Here’s the big confusion: Quicktime, AVI and
Real are not codecs!
 These are ‘container’ formats.
 This basically mean...
Video codecs can be broadly split into two types:
 frame-based codecs
 temporal (or field-based) codecs.
 Say What!?!
 Well known examples are Cinepak
and Motion-JPEG
 They work by examining and compressing each
frame of video individuall...
=
Time
 The best known is MPEG-2 (used for Digital TV &
DVDs)
 They watch how much a video clip changes from
frame to frame the...
=
+
+
+
Keyframe
=
+
+
+
Copies unchanged
parts of the keyframe
 The quick answer to this question is to use the
relevant presets within your editing software:
Codecs made Simple in iMo...
 But it’s always worth checking with your client
about their requirements.
Especially if they’re planning on showing the ...
Interlaced Progressive
 The ‘i’ and ‘p’ make all the difference!
 In terms of picture quality there is very little
between 1080i and 720p:
 10...
 1080p is the ideal format but broadcasters are not
yet equipping themselves to transmit in this format
(it takes up too ...
 These are rival disc formats – they are like super
large DVD discs (holding up to 50gb)
 ...this means that a HD movie ...
 Blu-Ray is supported by Sony,
Panasonic & Apple
 HD DVD is supported by Toshiba,
Microsoft & Intel
 This could be the ...
 At the other end of the resolution spectrum is the
booming mobile video market
 This is more concerned with getting fil...
 You can’t!
 Things are moving too fast, the best you can do
is be aware of the issues and make sure you
know the most c...
---End---
Formats andcodecs
Formats andcodecs
Formats andcodecs
Formats andcodecs
Formats andcodecs
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Formats andcodecs

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Formats andcodecs

  1. 1.  Why will your PC play some video files and not others? It’s all down to codecs.  So why do we need codecs?
  2. 2.  Video uses a lot of storage space on your PC/Mac.  For instance 5 minutes of captured camcorder footage uses about 1gb of storage.  On the plus side, storage is now cheap.
  3. 3.  The trouble really comes when trying to distribute the footage.  People don’t want to be given hard drives to plug in to their computer. They want DVDs, iPod videos, Sky & Freeview.  So the files need compressing to fit these media
  4. 4. ...the trouble is that there are hundreds (thousands?) of compression options!  So let’s start at the top...
  5. 5.  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)
  6. 6.  ...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 came digital!
  7. 7.  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...
  8. 8.  Instead of being imposed like the 1950 standards, the new standards were placed in competition with each other.  The theory was that the best standard would become dominant.  The actual result was a minefield of formats, containers and codecs...
  9. 9.  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
  10. 10.  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
  11. 11.  Sorenson  Indeo  Cinepak  Oh, and there’s an another pile of codecs for encoding audio files! ...eh, what about Quicktime and AVI?
  12. 12.  Here’s the big confusion: Quicktime, AVI and Real are not codecs!  These are ‘container’ formats.  This basically means that they contain codec compressed video and audio in one easy to play file.
  13. 13. Video codecs can be broadly split into two types:  frame-based codecs  temporal (or field-based) codecs.  Say What!?!
  14. 14.  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
  15. 15. = Time
  16. 16.  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 next.  Thus keeping file sizes down!
  17. 17. = + + + Keyframe
  18. 18. = + + + Copies unchanged parts of the keyframe
  19. 19.  The quick answer to this question is to use the relevant presets within your editing software: Codecs made Simple in iMovie
  20. 20.  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!)
  21. 21. Interlaced Progressive
  22. 22.  The ‘i’ and ‘p’ make all the difference!  In terms of picture quality there is very little between 1080i and 720p:  1080i has a slightly higher resolution but it’s not very sharp with fast moving action...  ...so 720p is favoured by sports networks
  23. 23.  1080p is the ideal format but broadcasters are not yet equipping themselves to transmit in this format (it takes up too much bandwidth!)  Also known as ‘Full/True High Definition’ or ‘24p’  So it is currently being used as an alternative to expensive film-stock when actually shooting a TV or movie film production
  24. 24.  These are rival disc formats – they are like super large DVD discs (holding up to 50gb)  ...this means that a HD movie (which obviously has a larger file size) could fit on one of these discs rather than span across five DVDs  They are nothing (directly) to do with video formats
  25. 25.  Blu-Ray is supported by Sony, Panasonic & Apple  HD DVD is supported by Toshiba, Microsoft & Intel  This could be the next ‘VHS vs Betamax’
  26. 26.  At the other end of the resolution spectrum is the booming mobile video market  This is more concerned with getting files smaller to fit on the tiny screen on your phone or iPod  Typical Screen Res is a tiny 176 x 144
  27. 27.  You can’t!  Things are moving too fast, the best you can do is be aware of the issues and make sure you know the most common settings you work with  And always keep a copy of your finished video at the highest quality it was produced at!
  28. 28. ---End---

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