Or, how to make it all fit! DIGITAL VIDEO FILES AND COMPRESSION STANDARDS

Video Formats  Standard Definition: 720 pixels by 480 pixels

Video Formats  Standard Definition: 720 pixels by 480 pixels  High Definition: 1280 pixels by 720 pixels

Video Formats  Standard Definition: 720 pixels by 480 pixels  High Definition: 1280 pixels by 720 pixels  High Definition: 1920 pixels by 1080 pixels

Video Formats  Standard Definition: 720 pixels by 480 pixels  High Definition: 1280 pixels by 720 pixels  High Definition: 1920 pixels by 1080 pixels  2K Film Definition: 2048 pixels by 1536 pixels

Video Formats  Standard Definition: 720 pixels by 480 pixels  High Definition: 1280 pixels by 720 pixels  High Definition: 1920 pixels by 1080 pixels  2K Film Definition: 2048 pixels by 1536 pixels  4K Film Definition: 4096 pixels by 3072 pixels

Video Formats  Standard Definition: 720 pixels by 480 pixels  High Definition: 1280 pixels by 720 pixels  High Definition: 1920 pixels by 1080 pixels  2K Film Definition: 2048 pixels by 1536 pixels  4K Film Definition: 4096 pixels by 3072 pixels  8K Film Definition: 8192 pixels by 6144 pixels

Pixel Counts:  720 x 480 = 345,600 pixels  1280 x 720 = 921,600 pixels  1920 x 1080 = 2,073,600 pixels  2048 x 1536 = 3,145,728 pixels  4096 x 3072 = 12,582,912 pixels  8192 x 6144 = 50,331,648 pixels

Bit Depth  Each pixel consists of varying amounts of red, blue and green (RGB color) The various amounts of each primary color control the final color of the pixel

Bit Depth  Each pixel consists of varying amounts of red, blue and green (RGB color) The various amounts of each primary color control the final color of the pixel  In standard 8 bit color each of the 3 component colors has an 8 bit value, or 256 levels. This gives a total of more than 16 million shades and colors.

Bit Depth  Each pixel consists of varying amounts of red, blue and green (RGB color) The various amounts of each primary color control the final color of the pixel  In standard 8 bit color each of the 3 component colors has an 8 bit value, or 256 levels. This gives a total of more than 16 million shades and colors.  HD video often has 10 bit color (1024 levels) which provides more than 1 billion shades and levels

Bit Depth  Each pixel consists of varying amounts of red, blue and green (RGB color) The various amounts of each primary color control the final color of the pixel  In standard 8 bit color each of the 3 component colors has an 8 bit value, or 256 levels. This gives a total of more than 16 million shades and colors.  HD video often has 10 bit color (1024 levels) which provides more than 1 billion shades and levels  Some film formats offer 12, or even 16 bit color

Bit Depth  The primary advantage of additional bit depth is not more colors but more dynamic range. (levels of shading from complete black to pure white.)

Bit Depth  The primary advantage of additional bit depth is not more colors but more dynamic range. (levels of shading from complete black to pure white.)  Some versions of 2K, 4K, and 8K files use “logarithmic” bit systems to give even more dynamic range.

Uncompressed File Sizes  To determine the theoretical size of a video file you simply have to multiply!  Multiply the number of total pixels by the number of colors by the bit depth to find total bits per frame.  Multiply the frame rate (frames per second) by the total number of seconds to arrive at a final file size in bits.  Divide that number by 8 to get the number of bytes.

Uncompressed File Sizes  1 frame of Standard Definition: 1,036,800 bytes (1 MB)

Uncompressed File Sizes  1 frame of Standard Definition: 1 MB  1 frame of 1280 x 720 HD: 2.8 MB

Uncompressed File Sizes  1 frame of Standard Definition: 1 MB  1 frame of 1280 x 720 HD: 2.8 MB  1 frame of 1920 x 1080 HD: 6.2 MB

Uncompressed File Sizes  1 frame of Standard Definition: 1 MB  1 frame of 1280 x 720 HD: 2.8 MB  1 frame of 1920 x 1080 HD: 6.2 MB  1 frame of 1920 x 1080 HD (10 bit): 7.8 MB

Uncompressed File Sizes  1 frame of Standard Definition: 1 MB  1 frame of 1280 x 720 HD: 2.8 MB  1 frame of 1920 x 1080 HD: 6.2 MB  1 frame of 1920 x 1080 HD (10 bit): 7.8 MB  1 frame of 2K Digital Film: 11.8 MB

Uncompressed File Sizes  1 frame of Standard Definition: 1 MB  1 frame of 1280 x 720 HD: 2.8 MB  1 frame of 1920 x 1080 HD: 6.2 MB  1 frame of 1920 x 1080 HD (10 bit): 7.8 MB  1 frame of 2K Digital Film: 11.8 MB  1 Frame of 4K Digital Film: 47.2 MB

Uncompressed File Sizes  1 frame of Standard Definition: 1 MB  1 frame of 1280 x 720 HD: 2.8 MB  1 frame of 1920 x 1080 HD: 6.2 MB  1 frame of 1920 x 1080 HD (10 bit): 7.8 MB  1 frame of 2K Digital Film: 11.8 MB  1 Frame of 4K Digital Film: 47.2 MB  1 frame of 8K Digital Film: 188 MB

Uncompressed File Sizes  1 frame of Standard Definition: 1 MB = 1.4 GB/min  1 frame of 1280 x 720 HD: 2.8 MB = 4 GB/min  1 frame of 1920 x 1080 HD: 6.2 MB = 9 GB/min  1 frame of 1920 x 1080 HD (10 bit): 7.8 MB = 11 GB/min  1 frame of 2K Digital Film: 11.8 MB = 17 GB/min  1 Frame of 4K Digital Film: 47.2 MB = 68 GB/min  1 frame of 8K Digital Film: 188 MB = 270 GB/min

Compression  In the Computer world compression is the act of taking a large file and making it smaller.

Compression Advantages:  Less storage space needed (saves $$$)

Compression Advantages:  Less storage space needed (saves $$$)  Faster processing times

Compression Advantages:  Less storage space needed (saves $$$)  Faster processing times  Faster transmission speeds (smaller bandwidth requirement)

Compression Disadvantages  Degrades Quality

Compression Disadvantages  Degrades Quality  Difficult to do well

Compression Disadvantages  Degrades Quality  Difficult to do well  Must be de-compressed before using

Compression Disadvantages  Degrades Quality  Difficult to do well  Must be de-compressed before using  Can make some types of processing more difficult

Types of Compression  Lossless: meaning that no data is actually lost  An example would be a “zip” file  Not effective for audio or video  “Lossy”: Meaning that some data is actually lost  An example would be an MP-3 file  Useful for audio and video files

Compression Ratio  A simple comparison of the size of the file before compression to the size of the file after compression  Example: a 10 MB photo file is compressed down to 1 MB. That is a 10-1 compression ratio.  It is not unusual for video files to be compressed at a ratio of 10 or 20 to 1. (or even more!)

Compression Standards  A compression algorithm is a mathematical formula used to determine which bits of data can be eliminated.  The same standard can then be used at the end to “de-compress” the file for playback.

Compression Standards  JPEG: Originally used for still pictures  MPEG-1: First video standard. Supports low bit rates (also the basis for MP-3 audio)  MPEG-2: DVD standard  MPEG-4: High Quality – Blue Ray standard  MPEG-7: Currently under development

Basic Compression Concepts  Intra-frame coding: Each frame stands on its own and is compressed individually. This has advantages:  Easier to process  Much easier to edit  More difficult to corrupt

Basic Compression Concepts  Inter-Frame Coding: Information from one frame is used to help compress surrounding frames.  I- frame: Complete on it’s own  P-frame: Predictive coded frames  B-frame: Bidirectional Predictive coded frames  Typically every 15 th frame or so is made into an “I” frame. P-frames and B-frames might follow like this: IBBPBBPBBPBBPBB(I) to form a Group of Pictures (GOP)

MPEG-2  Currently the standard for video compression

MPEG-2  Currently the standard for video compression  Serves as a general standard. Different institutions can adapt it to their use.

MPEG-2  Currently the standard for video compression  Serves as a general standard. Different institutions can adapt it to their use.  Not very good at very low data rates.

MPEG-2  Applications (formats) include:  DVD-Video  HDV  XDCAM Data (from Sony EX type cameras)  DVB (Digital Video Broadcasting)  ATSC (US High Definition Broadcasting)  Earlier computer compression standards

MPEG-4  New emerging standard for video compression  Still a general standard – adaptable by different institutions  Much higher quality than MPEG-2, but requires more computing power.  Supports Digital Rights Management

MPEG-4  Applications (formats) include  Quicktime 6 and above  DivX  H-264 standards  Digital AVC  Blu-Ray Video Discs  Newest versions of WMV files  Real Video Files