• Advice 1: Stick to one format. Hard/painful to mix
• Advice 2: Please don't use 4K for this class

Modes we need to understand:
HD: 4K, 1080p, 1080i, 720p

• Resolution: Pixels dimensions of your video
  
  
  
  
  
  4K (we won't be using this in class. Too big == takes too long to do things)
  
  
  • 3840 x 2160 pixels
  
  
  HD: digital video with a resolution of at least 1280 x 720 pixels
  
  
  • HD
    • 1080 stands for 1920 x 1080 pixels
    • 720 stands for 1280 x 720 pixels
    • Aspect ratio: 16:9
    
    
    
  • SD (or SONY calls it STD)
    • 720x480 pixels
    • Aspect ratio 4:3 or 16:9
    
    
    
  • Why would we want 1080 or 720, 16:9 or 4:3?
  
  
  
  
  
• Frame rate
  • 60 fps (frames per second)
  • 30 fps
  • 24 fps
  • ... actually there are like 8 different frame rates being used in HD
  • why any of these framerates? why not 1?
  
  
  
  
• Scanning method: p or i
  
  Video is a series of still pictures displayed fast enough to create the illusion of motion. Scanning is the process of displaying pictures on the screen.
  
  
  • P (progressive scan) - display the entire image at once
    
    
  • I (interlaced) - each picture is divided into two fields composed of all the even lines in the image, followed by all the odd lines and displayed in sequence
    
    
  • why would one use interlaced?
    
    
    
    
    

    image From Final Cut Pro 7 Manual

    
    
    Effects of interlacing:
    
    
    
    
    
    • CRT (cathode ray tube) monitors: electron gun draws lines of light on the screen left-to-right, top-to-bottom
      
      
    • Flat panel: composed of fixed grid of pixels.
  
  
  "Interlaced video is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. It effectively doubles the time resolution (also called temporal resolution) as compared to non-interlaced footage (for frame rates equal to field rates)." (from Wikipedia)
  
  
  
  So in summary, HD TV has three modes:
  
  720p
  
  - progressive video
  - resolution: 1280 x 720
  - used in: broadcast television, internet downloads/streaming, video games, artists video
  1080i
  
  - interlaced video
  - resolution: 1920x1080
  - used in: broadcast television, internet downloads/streaming, video games, artists video
  - not necessarily better than 720p. 720p suited for high-motion subjects.
  
  

  • ESPN, ABC, and Fox use 720p
  • PBS, CBS, NBC, and HBO use 1080i
  • List of current American high-definition channels
  1080p
  
  - progressive video
  - resolution: 1920 x 1080
  - used in: Blu-ray, internet downloads/streaming, video games, artists video
  
  Look at the sample video files in the Media folder in the Google Drive folder to see the difference between video standards.

Youtube has a 1080p option. But it is not necessarily better quality than broadcast HD. Why?

• Aspect ratio
• Resolution
• Scanning method
• Frame rate
• Data rate or aka. bit rate

Data rate conveys how many bits that are processed per second. Even in the same standard (eg. 1080p), if the videos are compressed differently, they will have different data rates. Generally image quality degrades the more you compress. Data rate correlates to file size as well.

Thus a broadcast 720p may look much better than a highly compressed youtube 1080p file.

Video stored as a file on the computer has two parts

• Container/wrapper (aka. file format) -- mov, mp4, wmv, mts...etc)
• Codec

Quicktime or Windows Media File is a wrapper/container:



Codec: "coder-decoder" or "compressor-decompressor". So what is contained in the wrapper is a compressed video/audio file.


For hand-ins, I will ask you to use the H.264 codec in mp4 file format.

Image from Wikimedia Commons by Allon ROTHFARB

The first line of pixels can be represented as

wwrrrrwwwwwrrrrww

Alternatively,

2w4r5w4r2w

Can continue not ending at the end of the line. The longest part would be

59r

instead of

rrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr

This is called a "lossless" compression because you can decompress to the original image. "lossy" compression algorithms sacrifice quality/fidelity in order to make the files larger. More complex the algorithm is the more computing power required.

This example only used the spacial dimension to compress but video compression also uses the temporal dimension.

• how to export your sequence to a video you can share

• Power On/Off
• Battery (DC in)
• Lens
• Viewfinder
• LCD screen
• Record button
• Microphone and Headphone sockets
• Internal Storage
  • MiniDV tape
  • DVD
  • hard disk
  • flash memory
• Zoom: W <--> T
• Manual focus
• Threaded hole for tripod mount
• Interface to connect to computer/TV (USB/HDMI)

When you checkout a camera, I want you to look for the following. I strongly suggest you choose the same image quality for all your footage for a project. Dealing with different quality footage is a nightmare. (Merging 24 fps footage with 30 fps footage?)

• Exposure -- How much light to let in. Controls how dark or bright your video is
• White balance -- Controls the color temperature of your video.
• Shutter speed -- Changes how moving things look. Motion blur with slow shutter speed.
  
  
• Image Quality (Video Format)
  • For older Sony flash based cameras
  Menu -> Image/Quality/Size:
  
  

  • HD (which is actually AVCHD) or STD
  • Frame Rate 60p , 60i, 24p
  • if you select anything other than 60p, you will get the option of FX, FH, HQ, LP.
    These options give you the choice of data transfer rates
    

    HD: 1920x1080 STD: 720x480
    60p (PS quality: 28Mbps)
    60i (FX 24Mbps, FH 17M, HQ 9M)
    24p (FX: 24Mbps, FH 17Mbps)
    

  • For newer Sony cameras (CX900)
  Menu -> Image/Quality/Size:
  
  
  • File format XAVC S 4K (do not use for class), XAVC S HD (high data rate) or AVCHD (lower data rate)
  • Framerate 60p, 30p, 24p
  • For Nikon D7X00 cameras
  Turn the mode to video (#54) in picture below and turn on Live View (#53). Hit the info button (#39).
  • Image area: DX or 1.3x(cropped)
  • In cropped 1080 60p or 24p, in DX full frame 1080 24p

users guide

- manual control for exposure, focus, shutter-speed
- has night vision
- smooth slow record high-framerate capture (3 seconds into 12 second long slow-motion)
- can be used as a projector

- Better optics. More manual control (eg. depth-of-field) through aperture/shutter speeds.
- Interface slightly more complicated (designed originally to take photos)



Key points:
- You can use the main menu to change the video format or you can hit the info button while in video mode

- If you want autofocus, you really want to use continuous autofocus (AF-F). If you use regular autofocus for photography, the camera will focus with jerky movement.
Use manual focus by manually turning the focus ring on the lens or turn on continuous autofocus. Press the Focus-mode selector button (#26 on the picture) and rotate the Main command dial (#47 in the picture)



from https://www.youtube.com/watch?v=NW5KfzXo43M