Comparing: VGA, DVI, HDMI, DP

A quick walkthrough to understand the technical evolution happening across those standards.

Transcript

1. Comparing: VGA, DVI, HDMI, DP -- Tarek ELDEEB
2. What are the basic video signals? • It all started with the analog TV 1. Line marker (Horizontal sync) 2. Frame marker (Vertical Sync) 3. Color Data for each line • Going Digital needs an extra CLK ◦ Either SRC+Display agree on a frequency (set) ◦ Send the CLK from SRC → Display • What about the audio?
3. VGA • Introduced in 1987: Basic Video, no audio • Initially supporting up to 640×480 ◦ Now 1080p60 and above • Analog color data (0 → 5v), no clear/sharp images • Not hot-pluggable
4. DVI • Introduced 1999, DDWG • Digital and/or Analog Links ◦ Analog is backward compatible with VGA ◦ Digital has 3 differential (TDMS) + 1 Clk ▪ Clock is allowed to vary 25 → 165 MHz • Maximum data rate (including 8b/10b overhead) is 4.95 Gbit/s @ 165 MHz • UXGA (1600 × 1200) @ 60 Hz • I2C for EDID block: ◦ The display's identification ◦ color characteristics (such as gamma value), ◦ and table of supported video modes (resolutions)
5. HDMI • Introduced in 2004, proprietary, actively maintained • Backward compatible with DVI (digital) • Audio + Data streams are interleaved with Video • HDMI 1.4 added HEC: Back audio + Ethernet • Maximum data rate of 42 Gbps • HDMI 2.1 supports 8K@120Hz >> More features: 3D, Content Protection, CEC, .. etc
6. DisplayPort • Introduced on 2008 by VESA (open standard) • Uses 1-4 LVDS channels + 1 data ◦ No clock: Trained using a predefined set ◦ Data streams are packetized (future proof) • Backward compatible with HDMI, but lacks CEC • DP v2.0 supports maximum data rate of 80 Gbps • Supports 16K display @ 60Hz and 30 bpp HDR • Supports compression and multiple devices • Has many variants: mini, micro, embedded, wireless, USB-C ! Lane-0 Lane-1 Lane-2 Lane-3 AUX 3v3 Pwr
7. Comparison Audio Digital EDID Data Cable Length Max Resolution License VGA 45m 1920×1080 @60Hz DVI ✓ (TDMS) ✓ 4.5m 1600×1200 @60Hz HDMI ✓ ✓ (TDMS) ✓ ✓ (HEC,CEC) 15m 7680×4320 @120Hz ❌ DP ✓ ✓ (LVDS, packets) ✓ ✓ (AUX) 1.8m 15360x8460 @60Hz +HDR
8. Other Display Technologies • Mobile Industry Processor Interface (MIPI): DSI & CSI ◦ 1-4 LVDS Channels (like DP) + 1 CLK Channel (like HDMI) ◦ Commonly known as Flat Panel Display: FPD-Link ◦ DSI/CSI-2 released in 2021 supporting Automotive Lidars/Camera ▪ IEEE 2977-2021: A-PHY • Thunderbolt (from Apple/Intel): ◦ Similar to the MiniDP but with 8 LVDS Lanes ◦ Supports PCIe, Newer versions use the USB-C connector • USB-C Alt-Mode (10Gbps + 100W power) ◦ Non-USB data, DisplayPort 1.3 support