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These smart peripheral protocols suck balls. The VGA->DVI->HDMI chain retained the following simplicity of: 1. Send color of pixel 2. At the end of the line +
by torginus 3mo ago
These smart peripheral protocols suck balls.
The VGA->DVI->HDMI chain retained the following simplicity of: 1. Send color of pixel 2. At the end of the line + blank send a pulse on HSYNC pin 3. At the end of the screen send a signal on the VSYNC pic. That's it (almost, there's EDID). If you can implement this, chances are you can display what's sent down the cable accurately.
Likewise with audio, you just send a voltage level down the cable, if you want to be fancy, you use SPDIF, in which case you send a 16-24 bit number per channel.
That's it, no handshake, no negotiation.
I have a TB dock for my Macbook. Sometimes it doesn't register. Sometimes it reboots for some reason, giving me 10 seconds of black screen. There's a 10% chance on every connect or reboot that it will just plainly not work.
And it's way better than it used to be, but still pretty bad.
- mschuster91 3mo ago> That's it, no handshake, no negotiation. The thing is, the old protocols all have their limitations. Analog audio - unless it's balanced - is highly vulnerable to all sorts of external interference. S/PDIF is normally two channels of PCM audio (that's decently easy), but it can carry up to 8 channels of variously compressed audio and not every sink or source supports all possible codecs (thanks to software patent licensing BS). In either case, 48 kHz sample rate and 20 bits precision are the fundamental limits. For video... analog maps well to CRT displays but reconstructing signals from analog inputs in a TFT/LED screen is inherently a lossy process, and running anything more than 1080p is a gamble and requires good, short cables. And digital video at higher data rates becomes a nasty mess and practically devolves into RF black wizardry at the kind of stuff you can pull off with modern digital video signalling - 4K @ 240 Hz refresh rate, this is utter insanity if you just think how much data is being shovelled around.
- torginus 3mo agoI an not suggesting analog.. HDMI and DVI are fully digital, yet they retain the same dead simple signaling of VGA... at least for sending images, all the added features on HDMI, such as content protection and embedding other signals into the blank period are just as sucky and error prone as other digital protocols.
- mschuster91 3mo ago> HDMI and DVI are fully digital, yet they retain the same dead simple signaling of VGA Not any more, that was my point. HDMI has adopted Display Stream Compression as well.
- wink 3mo agoYeah. HDMI sometimes shows the same signs of whatever is happening as DP. I still miss the old binary (works/doesn't work) nature of D-SUB and DVI. No autonegotiations or any "need to reset the power on the monitor"...