digital TV 1 Common Video File Types

digital TV. 1

Common Video File Types File Type Acronym For Originally Created By File Info & Compression Platforms . mov Quick. Time movie Apple • Also audio-only • Can be streamed • "Fast start" • Common compression methods: H. 264, Sorenson Video, Animation Apple Quick. Time player, which is available for Mac and Windows . avi Audio Video Interleave Intel Common compression methods: Microsoft RLE, Intel Indeo Video Primarily used on Windows but Apple Quick. Time player can play AVI files . mpg. mpeg MPEG Motion Picture Experts Group • For DVD-video • High definition HDV Cross-platform Div. X, Inc • Uses Div. X codec, which is based on MPEG-4 • Popular format for movies because of the high • image quality and small file size • AVI is a common container file format • May require downloading Div. X codec • Windows Media Player v 11. 0 comes with Div. X codec . divx 2

Common Video File Types File Type Acronym For Originally Created By File Info & Compression Platforms . mp 4 MPEG-4 Moving Pictures Experts Group • Video codec: H. 264 • Audio codec: AAC • One of the HTML 5 video formats Plays in Web browsers that support the MP 4 format of HTML 5 video (Safari and IE) . ogg or. ogv Audio Video Interleave Xiph. Org Foundation • Video codec: Theora • Audio codec: Vorbis • One of the HTML 5 video formats • Compared to the other two HTML 5 video formats, it has lower quality for the same file size Plays in Web browsers that support the OGG format of HTML 5 video (Firefox, Chrome, Opera) An open source video format from Google • Video codec: VP 8 • Audio codec: Vorbis • One of the HTML 5 video formats Plays in Web browsers that support the Web. M format of HTML 5 video (Firefox, Chrome, Opera) . webm 3

Common Video File Types File Type Acronym For Originally Created By File Info & Compression Platforms . flv Flash Video Adobe • Progressive download • Can be streamed • Cross-platform • Requires Adobe Media Player to play • Common compression methods: H. 264, Sorenson Spark, On 2 VP 6. f 4 v Flash Video Adobe . wmv Windows Media Microsoft • Builds on MPEG-4 Part 12 • Supports H. 264/ACC-based content • A newer Flash Video format than flv • Cross-platform • Requires Adobe Media Player to play • Can be embedded in Flash SWF files Requires Windows Media Player to play 4

File Size considerations • For Web: – high compression – streaming video • CD-ROM or DVD-ROM playback: – use data rate that can be handled by your target audience's computer • DVD-video: (DVD) – MPEG-2 (DVD) – Mp 4 -/H. 264 container, compressed =h. 264 used for virtually video today 5

If going to use Future Editing – Lower /no compression level – Choose uncompressed, if • the frame size is small • the video duration is extremely short • you have enough disk space 6

Video terms • • Dots Pixels Frame sizes Common Frame ratios (W: H): 16 x 9, 4 x 3 Interlaced vs progressive Dolly Pan 7

Some analog to -digital terms • • • Sample size Sample rate File sizes Frame size Apply to: HDTV, CD, 4 K. . eg next slide 8

need for compression The HDTV bandwidth information • Total pixels in each frame: 1920 1080 pixels = 2, 073, 600 pixels/frames • File size of a frame: 2, 073, 600 pixels/frames 24 bits/pixel = 37, 324, 800 bits/frame • • File size for 60 frames (1 second) 37, 324, 800 bits/frame 60 frames • = 2, 239, 488, 000 Gb per second 2 Gbps 9

4 K • Another HDTV standard is 4 K • What is its frame size and sample rate • Calculate bps, as on previous slide 10

Question 1 -CDs • Look up definitions of • sample rate – Lookup Nyquists theorem – What is the highest frequency we can hear (OK, women hear higher) • • Sample size definition Sample size for CD? Max time length of a CD Calculate maximum total file size of CD 11

DVD Question #2 • same questions as for CD, just different values result. i. e. what would be the total file size for a 1 second of a DVD sound 12

Question 4 • List at least 3 ways computers compress videos as per video we watched 13

Review Question Name several strategies to reduce the file size of a video. 14