do any macs output to 1080i. TL:DR --- NO (as far as i can tell)

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Level 1

4 points

do any macs output to 1080i. TL:DR --- NO (as far as i can tell)

Similar question here, thread was locked so I wanted to provide some findings and save a headache for others.

1080i 50hz outputting as 1080p 25hz - Apple Community

I am also trying to use macs running HDMI into an "older" ATEM (ATEM production studio 4K). For those that don't know, older ATEM models have a limitation that it will only display inputs that match, exactly, the standard that is set in ATEM settings (gear icon, general tab, video).

I tested with 4 mac models and got a whole host of variations. Most interesting thing, even when Mac external display is set to "1920x1080" output resolution (as measured via pass thru with a decimator), is still 2160p at 24,25,30MHz.

I don't fully understand this, but my guess is that, if the Mac video card detects it CAN output a 2160 signal, it does, then modifys the screen to appear as a 1080 size. This is an issue for the ATEM or other monitors that can accept 4K but you don't want them to.

Solution: I converted my ATEM to 1080p 50. It was the only standard that would support all my MAC machines. Thankfully, my windows machines, and my PTZ cams can all output that standard.

I tried using SwitchResX before I went down this path and could not get it to output any other signals. All the settings I wanted were greyed out. It was the trial version, but it claimed to be fully functional for some time.

BMD and Decimator converters will solve these issues, but it would be great if you didn't have to have buy gear. And as of this writing, its all on backorder anyway :0

full test results below for the very technical, this is things that worked with the switcher.

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PTZ cams – 1080i 59.94 (default)

1080p:25, 29.97, 50, 59.94.

1080i: 50, 59.94

Win laptop old – HP Zbook studio G4 – intel i5-7440hQ @2.80ghz – win 10 pro 22H2, build 19045.2846

works with most resolutions (via advanced display tab)

4K: 23.98, 24, 25, 29.97

1080i: 59.94, 50

1080p: 50, 59.94

Wont work: 1080i 60

1080p output shows up as 2160p in decimator for 23.98, 24, 25, 29.97, 30)

Mac laptop new

2160p: 24, 25, 30

1080x: Native NONE - output shows up as 2160p in decimator for 24, 25, 30)

If ran through HDMI--> sdi converter and “forced to hd”: 1080p: 24, 25, 30, 50, 60

Mac laptop old – mac Mojave (13” mid 2012) 2.5ghz i5. 4gb 1600 DDR3

1080p: 24, 25 (not 50)

1080i: 50

Mac mini new – montery 12.3.1 – Mac mini (M1 2020), Apple M1 chip, 16gb ram

2160p: 24, 25 (also outputs 30, 50,60 but ATEM 4K does not support)

1080x: NONE - output shows up as 2160p in decimator for 24, 25, 30)

Mac mini old – montery 12.6.5 – mac mini (late 2014). 2.6ghz dual core intel i5. 8gb memory, DDR3 1600

2160p: 24, 25

1080p: 24, 25, 50

1080i: none that I can find

1920x1080 setting in display properties, displays at 1920x1080 pixels but pushes 2160p to switcher (ie, it sends a 2160 signal and doubles the size of items on screen, or something similar)

Posted on Apr 13, 2023 6:24 PM

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Answer 1

Top-ranking reply

Chance08

Level 2

371 points

Apr 17, 2023 4:37 PM in response to overtony

Based on the information provided in the test results, it appears that none of the Mac laptops or Mac minis tested output a native 1080i signal. The closest standard that some of the Macs can output is 1080p at either 24, 25, 50, or 59.94 Hz. It seems that even when the external display is set to 1920x1080, the output signal is still being sent at 2160p, and the Mac modifies the screen to appear as a 1080 size. This could be an issue for older ATEM models or other monitors that can accept 4K but are not intended for that use. The solution mentioned was to convert the ATEM to 1080p 50, which was the only standard that would support all the Mac machines.

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Answer 2

Sep 18, 2023 10:02 AM in response to Lanny

Plenty of computers output 1080i, including Macs which are able to do this with all versions of MacOS before Big Sur.

While you're right about this being an old standard used with CRTs in mind, you may not be aware that plenty of broadcast-quality digital cameras and vision mixers also use a version of interlacing in order to push sufficient data through to build a 1080 image using half the data each frame to work around the limitations of some slightly older hardware (not necessarily CRTs!). Typically, 1080i is used at 50 frames per second in a way that locks every second frame together, so that the equivalent of 1080p is displayed at 25 frames per second without interlacing artefacts.

It's surprising to me that Apple simply removed support for this widely used standard, but some of the comments here demonstrate how not everyone understands how it's been used!

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Answer 3

overtony Author

Level 1

4 points

Apr 25, 2023 9:38 PM in response to Lanny

The Windows machine i tested above had many options for outputting interlaced signals. See above test results.

The machine I am on now, does not (or possibly the external displays I'm using wont support it). My understanding is it depends on what the display can handle, that determines what the card options will output. But I am not 100% sure of this.

Either way, The windows machine output 1080i 50 + 59.94, and the oldest mac output 1080i 50

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Answer 4

Lanny

Level 6

13,225 points

Apr 18, 2023 8:26 AM in response to overtony

No, AFAIK, no computers output 1080i, it's standard used for old CRT TVs.

Note: 1080i and 1080p are the same resolution, the "i" stands for interlaced used to decrease the bandwidth needed for broadcasting video for TVs that used cathode ray tubes (CRTs).

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Answer 5

Lanny

Level 6

13,225 points

Apr 25, 2023 10:31 PM in response to overtony

Note:

Hertz is abbreviated as Hz, not hz

Giga is abbreviated as G, not g.

Byte is abbreviated as B, not b.

g = gram or the acceleration of gravity

b = bit

The letter's case matters.

Old computers used CRT TVs for monitors, so interlacing would have been needed. But, CRTs specifically designed to be computer monitors were generally capable of at least 480p.

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Answer 6

MEGA49R

Level 2

218 points

Apr 28, 2023 8:50 AM in response to Lanny

Also, all CRT’s emit LOTS of soft X-rays which are VERY harmful… I wouldn’t use CRT’s if I were you. Can lead to cancer and other health problems.

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