| Revision as of 17:12, 6 January 2017 editLambtron (talk | contribs)Extended confirmed users11,112 edits →Recording to a computer: clarifiction← Previous edit | Revision as of 03:59, 7 January 2017 edit undoLambtron (talk | contribs)Extended confirmed users11,112 edits →HDMI specifications: Deleted this section, which probably belongs in HDMI but definitely does not belong hereNext edit → | ||
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| *10-bit, 1920x1080 @ 50i = 198 MB/s, or 695 GB/h | *10-bit, 1920x1080 @ 50i = 198 MB/s, or 695 GB/h | ||
| *10-bit, 1920x1080 @ 60i = 237 MB/s, or 834 GB/h | *10-bit, 1920x1080 @ 60i = 237 MB/s, or 834 GB/h | ||
| ==HDMI specifications== | |||
| According to ] 1.3a spec.<br /> | |||
| Detailed timing is found in CEA-861-D or a later version of CEA-861 for the following video format timings. HDMI 2.0 supports higher resolutions, which are defined in CEA-861-F. | |||
| Cameras mostly use the ] format: for example a 25p/30p ] is transported in a 50i/60i ] format respectively, but with identical information: No ] should be used. | |||
| ;Primary video format timings | |||
| • 640x480p @ 59.94/60 Hz<br /> | |||
| • 1280x720p @ 59.94/60 Hz<br /> | |||
| • 1920x1080i @ 59.94/60 Hz<br /> | |||
| • 720x480p @ 59.94/60 Hz<br /> | |||
| • 720(1440)x480i @ 59.94/60 Hz<br /> | |||
| • 1280x720p @ 50 Hz<br /> | |||
| • 1920x1080i @ 50 Hz<br /> | |||
| • 720x576p @ 50 Hz<br /> | |||
| • 720(1440)x576i @ 50 Hz | |||
| ;Secondary video format timings | |||
| • 720(1440)x240p @ 59.94/60 Hz<br /> | |||
| • 2880x480i @ 59.94/60 Hz<br /> | |||
| • 2880x240p @ 59.94/60 Hz<br /> | |||
| • 1440x480p @ 59.94/60 Hz<br /> | |||
| • 1920x1080p @ 59.94/60 Hz<br /> | |||
| • 720(1440)x288p @ 50 Hz<br /> | |||
| • 2880x576i @ 50 Hz<br /> | |||
| • 2880x288p @ 50 Hz<br /> | |||
| • 1440x576p @ 50 Hz<br /> | |||
| • 1920x1080p @ 50 Hz<br /> | |||
| • 1920x1080p @ 23.98/24 Hz<br /> | |||
| • 1920x1080p @ 25 Hz<br /> | |||
| • 1920x1080p @ 29.97/30 Hz<br /> | |||
| • 2880x480p @ 59.94/60 Hz<br /> | |||
| • 2880x576p @ 50 Hz<br /> | |||
| • 1920x1080i (1250 total) @ 50 Hz<br /> | |||
| • 720(1440)x480i @ 119.88/120 Hz<br /> | |||
| • 720x480p @ 119.88/120 Hz<br /> | |||
| • 1920x1080i @ 119.88/120 Hz<br /> | |||
| • 1280x720p @ 119.88/120 Hz<br /> | |||
| • 720(1440)x480i @ 239.76/240 Hz<br /> | |||
| • 720x480p @ 239.76/240 Hz<br /> | |||
| • 720(1440)x576i @ 100 Hz<br /> | |||
| • 720x576p @ 100 Hz<br /> | |||
| • 1920x1080i @ 100 Hz<br /> | |||
| • 1280x720p @ 100 Hz<br /> | |||
| • 720(1440)x576i @ 200 Hz<br /> | |||
| • 720X576p @ 200 Hz | |||
| ;Pixel encodings and color depth | |||
| There are three different pixel encodings that may be sent across an HDMI cable: ] ], ] 4:2:2 and ] 4:4:4. <br /> | |||
| There are four color depths supported: 24-, 30-, 36- and 48-bits per pixel. | |||
| In HDMI 2.0, it is possible to transmit 4:2:0 chroma subsampling, but only in 4K50 and 4K60 resolution. | |||
| ==See also== | ==See also== | ||
Revision as of 03:59, 7 January 2017
Uncompressed video is digital video that either has never been compressed or was generated by decompressing previously compressed digital video. It is commonly used by video cameras, video recording devices (including general purpose computers), and in video processors that perform functions such as image resizing, image rotation and text and graphics overlay. It is conveyed over various types of baseband digital video interfaces, such as HDMI, DVI, DisplayPort and SDI.
Some HD video cameras output uncompressed video, whereas others compress the video using a lossy compression method such as MPEG or H.264. In the compression process, some of the video information is removed, which creates compression artifacts and reduces the quality of the video when decompressed. When editing video, it is preferred to work with video that has never been compressed as this maintains the best possible quality, with compression performed after completion of editing.
Recording
Standalone recorders
A standalone video recorder is a device that receives uncompressed video and stores it in either uncompressed or compressed form. These devices typically have a video output which can be used to monitor or playback recorded video. When playing back compressed video, the compressed video is uncompressed by the device before being output. Such devices may also have a communication interface, such as Ethernet or USB, which can used to exchange video files with an external computer, and in some cases control the recorder from an external computer as well.
Recording to a computer
Recording to a computer is a relatively inexpensive way to implement a digital video recorder, but the computer and its video storage device (e.g., solid-state drive, RAID) must be fast enough to keep up with the high video data rate, which in some cases may be HD video or multiple video sources, or both. Due to the extreme computational and storage system performance demands of real-time video processing, other unnecessary program activity (e.g., background processes, virus scanners) and asynchronous hardware interfaces (e.g., computer networks) may be disabled, and the process priority of the recording realtime process may be increased, to avoid disruption of the recording process.
Video capture interface
HDMI, DVI and HD-SDI inputs are available as PCI Express (partly multi-channel) or ExpressCard, USB 3.0 and Thunderbolt interface also for 2160p (4K resolution).
Software
Software for uncompressed video is often supplied with suitable hardware or available for free: Ingex (open source).
Wireless transmission
Wireless interfaces such as Wireless LAN (WLAN, Wi-Fi), WiDi, Wireless Home Digital Interface (WHDI), can be used to transmit uncompressed digital video at lower resolutions, but typically not at HD resolutions as even 1920x1080p@24 Hz requires a 1.2 Gbit/s data rate, which exceeds the maximum bandwidth of these interfaces (e.g., IEEE 802.11ac). The WirelessHD interface, however, which uses a 60 GHz wireless link, can transmit uncompressed digital video. The Wireless Gigabit Alliance also aims to use a 60 GHz wireless link. However, any disruption or bandwidth decrease of the wireless connection will reduce quality, or even stop the video recording.
Data rates
Uncompressed video has a constant bitrate that is based on pixel representation, image resolution, and frame rate:
- data rate = color depth * vertical resolution * horizontal resolution * refresh frequency
For example:
- 24-bit, 1080i @ 60 fps: 24 × 1920x1080 × 60/2 = 1.39 Gbit/s
- 24-bit, 1080p @ 60 fps: 24 × 1920x1080 × 60 = 2.78 Gbit/s.
4:2:2 format
The data rates and storage requirements for the widely used YCbCr 4:2:2 chroma subsampling format are listed below:
- NTSC
- 8-bit, 720x486 @ 29.97 fps = 20 MB/s, or 70 GB/h
- 10-bit, 720x486 @ 29.97 fps = 27 MB/s, or 94 GB/h
- PAL
- 8-bit, 720x576 @ 25 fps = 20 MB/s, or 70 GB/h
- 10-bit, 720x576 @ 25 fps = 26 MB/s, or 93 GB/h
- 720p
- 8-bit, 1280x720 @ 59.94 fps = 105 MB/s, or 370 GB/h
- 10-bit, 1280x720 @ 59.94 fps = 140 MB/s, or 494 GB/h
- 1080i and 1080p
- 8-bit, 1920x1080 @ 24 fps = 95 MB/s, or 334 GB/h
- 10-bit, 1920x1080 @ 24 fps = 127 MB/s, or 445 GB/h
- 8-bit, 1920x1080 @ 25 fps = 99 MB/s, or 348 GB/h
- 10-bit, 1920x1080 @ 25 fps = 132 MB/s, or 463 GB/h
- 8-bit, 1920x1080 @ 29.97 fps = 119 MB/s, or 417 GB/h
- 10-bit, 1920x1080 @ 29.97 fps = 158 MB/s, or 556 GB/h
1080i and 1080p RGB (4:4:4)
- 10-bit, 1280x720p @ 60 fps = 211 MB/s, or 742 GB/h
- 10-bit, 1920x1080 @ 24 fps = 190 MB/s, or 667 GB/h
- 10-bit, 1920x1080 @ 50i = 198 MB/s, or 695 GB/h
- 10-bit, 1920x1080 @ 60i = 237 MB/s, or 834 GB/h
See also
- List of video cameras supporting a raw format
- Data compression
- Nikon Expeed Video processor
- Uncompressed audio
- DPX and MXF files – used in professional video files systems
- TIFF files – used in AV and professional video files systems
References
- Using Uncompressed Audio and Video Streams Microsoft
- Compare USB Video Grabbers Epiphan
- Intensity models Blackmagic
- HD-SDI Express/34 Imperx
- OEM video card for 8-10-12-bit HD-SD SDI digital video to PCI Express Deltacast
- Capture Card Series Magewell
- DeckLink models Blackmagic
- Ingex Studio - Multi-camera Tapeless Recording
External links
- Video bitrate calculator Forret
- Uncompressed Digital Video Creative Planet Network
- Uncompressed vs. Compressed Video Creative Planet Network
- Master Guide to Rigging a Nikon D800 or D800E for Video Wolfcrow
Template:DSLR cameras with movie mode
| Video processing | |
|---|---|
| Post-processing | |
| Special processing | |
| High-definition (HD) | |
|---|---|
| Concepts | |
| Resolutions | |
| Analog broadcast (All defunct) | |
| Digital broadcast | |
| Audio | |
| Filming and storage | |
| HD media and compression | |
| Connectors | |
| Deployments | |