Multimedia

1. Multimedia Week 19 Animation, cameras and video

2. Last week • Lecture • Planning your model • Boolean • 2D to 3D • Polygon modelling Multimedia

3. This week • Animation • Cameras • Video • Streaming • Compression • Production Multimedia

4. Concepts • What is animation? • Modification of any kind of object • Light • Material • Camera • What can you change? • Parameters • Position • Rotation • Scale • What parameters have been changed? 3ds max v7 Multimedia

5. Frames • A series of still images • Frames • Persistence of vision • Illusion of fluid motion 3ds max v7 Multimedia

6. Frame rates • Frame rate • Speed at which the images are displayed • Frames per second • Different systems have different rates • Standard rate in UK for output to film is 24fps 3ds max v7 Multimedia

7. Timeline controls • VCR like section of the interface 9 Animation playback controls 10 Animation keying controls 14 Track bar 15 Time slider 3ds max v7 Multimedia

8. Key framing • Like traditional 2D animation techniques • Specific frames • Tweening • Computer calculates the parameters of the object’s position for each intermediate frame Multimedia

9. Time controls • Start or end • Default scene starts with 100 • If the output is set to 24 fps how long will this last? • Can be changed with the Time Configuration button • Auto Key • Move to a frame, transform objects or change their parameters. • All changes register as keyframes. Multimedia

10. Activity • Open up your model of a room • Save with a different name • Add something and make it move Multimedia

11. Constraints • Animation constraints are used to help automate the animation process. • Used to control an object’s • Position • Rotation • scale • A binding relationship with another object • Requires one object and at least one target object • The target imposes specific limits on the constrained object Multimedia

12. Motion paths • A path constraint restricts an object's movement along a spline • The spline curve (target) defines a path of motion for the constrained object. 3ds max v7 Multimedia

13. Pivot points and axes • An Orientation constraint causes an object’s orientation to follow the orientation of an object 3ds max v7 Multimedia

14. Cameras • Virtual cameras duplicate the functions and controls of real-world cameras • What controls does a real-world camera have? • Focal length • Field of View 3ds max v7 Multimedia

15. Focal length • The distance between the lens and the light-sensitive surface • Lens size • 28mm wide angled lens • 50mm normal lens • 85mm long focus • and more…. 3ds max v7 Multimedia

16. Field of view • Field of View • the width of your view as an angle with its apex at your viewpoint and the ends at the sides of the view • Relates to the lens size • 28mm wide angled lens • 75o • 50mm normal lens • 40o • 85mm long focus • 24o 3ds max v7 Multimedia

17. Creating cameras • Target • Free 3ds max v7 Multimedia

18. Free v. target • A Free camera has a single icon to animate • The Target camera has two • the target • the camera • You can switch between camera types, changing a Free camera to a Target and back again Multimedia

19. Camera view • Make the viewport active then press C key • The Viewport navigation controls change • Different controls for cameras than for the Perspective viewport • Dolly, pan, orbit Multimedia

20. Activity • Add a camera to your scene and view it through the viewport Multimedia

21. Pan Rotates the target about the camera Tilt or orbit Rotates a camera about the target Moving cameras 1 3ds max v7 Multimedia

22. Dolly Moves the camera and/or its target along the camera's main axis Truck Moves the camera parallel to the view plane Moving cameras 2 3ds max v7 Multimedia

23. Animating a camera • Following a moving object • Moving a camera along a track • Panning • Orbiting • Zooming 3ds max v7 Multimedia

24. Following a moving object • The Look-At constraint makes the object replace the camera’s target or • Link a target camera’s target to the object 3ds max v7 Multimedia

25. Zooming • Zooming moves toward or away from the camera’s subject matter by changing the focal length of the lens • It differs from dollying, which physically moves the camera but leaves the focal length unchanged 3ds max v7 Multimedia

26. Activity • Animate the camera view Multimedia

27. Discussion • How can you add a video to a multimedia production? Multimedia

28. Types rendering • Renders viewport view • Quick render • Render to file • Still image, frame • Animation • Render to print • Quicktime VR 3ds max v7 Multimedia

29. File types • The rendered output can be a still image or an animation • A selection of file types • AVI File (AVI) • BMP Image file (BMP) • Encapsulated PostScript format (EPS, PS) • JPEG File (JPG) • MOV QuickTime file (MOV) • PNG Image File (PNG) • TIF Image File (TIF) • Which are used for still or animation? Multimedia

30. Render output - avi • Compressor • Set the codec (compressor/decompressor) • Compression Quality • The higher you set the quality, the larger the file size will be. • Lossy technique • Keyframe Rate • Specify the interval between the delta keyframes used to compare one frame with another and generate in-between frames. 3ds max v7 Multimedia

31. NTSC uncompressed 640x480 pixels per frame x 3 bytes per pixel (24 bit colour) x 30 frames per second (approx) ≈ 26 MB per second ≈ 1.6 GB per minute PAL uncompressed 768x576 pixels per frame x 3 bytes per pixel (24 bit colour) x 25 frames per second ≈ 31 MB per second ≈ 1.85 GB per minute 191–192 Why compress? Chapman N and Chapman J (2004).

32. 197 Streamed Video • Play back a video stream as it arrives over a network (like broadcast TV), instead of downloading an entire video clip and playing it from disk (like renting a DVD) Chapman N and Chapman J (2004).

33. 198 HTTP Streaming • Start playing a downloaded clip as soon as enough of it has arrived • Starts when the (estimated) time to download the rest is equal to the duration of the clip Chapman N and Chapman J (2004).

34. 206–208 Video Compression • Spatial (intra-frame) compression • Compress each frame in isolation, treating it as a bitmapped image • Temporal (inter-frame) compression • Compress sequences of frames by only storing differences between them • Always some compression because of sub-sampling

35. 207 Spatial Compression • Image compression applied to each frame • Can therefore be lossless or lossy, but lossless rarely produces sufficiently high compression ratios for volume of data • Lossless compression implies a loss of quality if decompressed then recompressed • Ideally, work with uncompressed video during post-production

36. 207–208 Temporal Compression • Key frames are spatially compressed only • Key frames often regularly spaced (e.g. every 12 frames) • Difference frames only store the differences between the frame and the preceding frame or most recent key frame • Difference frames can be efficiently spatially compressed

37. 216 Vector Quantization • Divide each frame into small rectangular blocks (’vectors’) • Code Book – collection of constant vectors representing typical patterns (edges, textures, flat colour,…) • Compress by replacing each vector in image by index of vector from code book that most closely resembles it

38. 216–219 Codecs • Cinepak – Longest established, high compression ratio, takes much longer to compress than to decompress • Intel Indeo – Similar to Cinepak, but roughly 30% faster compression • Sorenson – More recent, higher quality and better compression ratios than other two • All three based on vector quantization • Quality of all three inferior to MPEG-4

39. 215 MPEG-4 • Standard defines an encoding for multimedia streams made up of different sorts of object – video, still images, animation, 3-D models… • Higher profiles divide a scene into arbitrarily shaped video objects each one may be compressed and transmitted separately, scene is composed at the receiving end by combining them

40. 230–236 Post-Production • Changing or adding to the material • Most changes are generalizations of image manipulation operations (e.g. colour correction, blurring and sharpening,…) • Compositing – combining elements from different shots into a composite sequence • Animating elements and combining animation with live action

41. 236–237 Preparing for Delivery • Compromises required to bring resource requirements of video within capabilities of delivery media (e.g. networks) and low-end machines • Reduce frame size (e.g. downsample to quarter frame) • Reduce frame rate (12fps is OK for smooth motion, flicker not a problem on computer) • Reduce colour depth

42. Resolution Height and width in pixels Consider aspect ratio Colour depth 8 bit allows 256 colours 24 bit allows 16 million More colours helps reduce banding and errors Anti-aliasing Active time segment Alpha channel Atmospherics Eg. fog Effects Eg. Blur Advanced lighting Use a radiosity solution or light tracing in the rendering Render output Render settings in Max Multimedia

43. Activity – output as a video • Create an animation and output as an AVI • Set the following • Active time segment • 320 x 240 • Files > Save as AVI • Give it a name and note where you are saving it • Click Setup • Use Sorenson compression • 15 fps • 50% compression • Click Render Multimedia

44. Self assessment • You have been asked to model a lecture theatre for Hope and produce an animated video showing the lecture theatre • Describe, compare and contrast 3 camera animations • Describe the process of output of the video with justification for choices of settings • Describe the purpose of video CODECS, how they work Multimedia

45. For Next Week • Work on Portfolio 2.2 • Work on the 3ds max tutorials • Directed reading • (DM) Chapter 9 • (GA) Chapter 9 Multimedia

46. References • Giambruno M, (2002) 3D Graphics & Animation, 2nd Edition, New Riders, ISBN: 0-7357-1243-3 • Kerlow I. V., (2003) The Art of 3-D Computer Animation and Effects , 3rd Edition, John Wiley & Sons Inc; ISBN: 0471430366 • Murdock K.L., (2005) 3DS Max 7 Bible, John Wiley & Sons Inc, ISBN: 0764579711 • Screen shots taken from 3ds max 7 User Reference Multimedia