Sidecar in macOS Catalina is limited to newer Macs, but there's a work-around

AppleInsiderAppleInsider
Posted:
in macOS edited August 2020
Sidecar, a feature in macOS 10.15 Catalina that can turn an iPad into a second monitor for a Mac, may be limited to only a small selection of newer Macs at first, with the first beta of the operating system preventing it from being used on a large number of older Macs.




Introduced on Monday as part of macOS Catalina, Sidecar is a feature of both macOS and iPadOS that extends the macOS desktop to the iPad's display. Able to be used both via a cable and wirelessly, the feature can make the iPad a mirrored display or a second screen, including effectively turning it into a graphics tablet when used with the Apple Pencil.

On Wednesday, developer Steve Trougton-Smith posted to Twitter the results of an exploration of the first macOS Catalina developer beta, including a list of devices that Sidecar will be supported on, as well as a blacklist for other hardware.

According to Troughton-Smith, Sidecar supports the 27-inch iMac from Late 2015, the 2016 MacBook Pro, 2018 Mac mini, the new Mac Pro, the 2018 MacBook Air, the Early 216 MacBook and newer models of each device.






While there is a blacklist preventing Sidecar's usage on older models, Troughton-Smith notes there is a terminal command that is supposed to enable it on earlier Macs running the beta, but it is apparently not guaranteed to work. The command reads:
defaults write com.apple.sidecar.display allowAllDevices -bool YES
It is unclear exactly why Apple is limiting the availability of Sidecar to newer devices, but as it is just the first beta, it is possible that Apple could open up support to earlier models ahead of macOS Catalina's release this fall.

AppleInsider will be reporting live throughout WWDC 2019, starting with the keynote on Monday, June 3. Get every announcement as it happens by downloading the AppleInsider app for iOS, and by making sure to follow us on YouTube, Twitter @appleinsider, Facebook and Instagram.
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Comments

  • Reply 1 of 27
    AppleZuluAppleZulu Posts: 2,007member
    One could imagine that older models might introduce additional variables to the mix. So it's probably easier in the first beta to keep it limited and resolve the first round of issues before introducing the possibility of additional problems. It's probably a good way to isolate issues.
    llamacaladanian
  • Reply 2 of 27
    ivanhivanh Posts: 597member
    It’s predictable and seemingly planned, like airdrop. Why giving you something new as free lunch?  That’s why Apple has to split into hardware, software and services individuals. 
  • Reply 3 of 27
    saareksaarek Posts: 1,523member
    I remember how I couldn’t get AirPlay to work on my 2010 iMac, but the knockoff application called AirParrot handled the task with ease.

    There won’t be a real technical reason, just Apple trying to push people to newer machines.
    ednl
  • Reply 4 of 27
    dempsondempson Posts: 62member
    The listed models have one feature in common: all have a Skylake or newer processor.

    Skylake adds hardware encode/decode support for HEVC, so this might just be a case of the Sidecar feature being implemented with HEVC rather than H.264 to reduce bandwidth requirements or allow a higher frame rate. Older Mac models would have to do HEVC encode in software, so enabling the workaround might impose a significant CPU performance load when the display is rapidly changing.

    If I'm right, this could impose a similar requirement on the receiving iPad: basic HEVC hardware decode is a feature of the A9 and later processors, so A8 models that can run iOS 13 (iPad Air 2 and iPad mini 4) may be unable to act as a sidecar receiver as they would have to decode the video stream in software.

    There was a similar cutoff with the introduction of AirPlay video support: it required a Sandy Bridge or later processor to get H.264 hardware encode support. Third party software (AirParrot) implemented that feature on older Macs by doing the H.264 encode in software, but it caused a fair amount of CPU overhead.
    edited June 2019 emoellersocalbrianracerhomie3netroxStrangeDayschasm
  • Reply 5 of 27
    aieronimoaieronimo Posts: 11member
    dempson said:
    The listed models have one feature in common: all have a Skylake or newer processor.

    Skylake adds hardware encode/decode support for HEVC, so this might just be a case of the Sidecar feature being implemented with HEVC rather than H.264 to reduce bandwidth requirements or allow a higher frame rate. Older Mac models would have to do HEVC encode in software, so enabling the workaround might impose a significant CPU performance load when the display is rapidly changing.

    I have a late 2015 iMac 27-inch, which is listed as one of the supported models for Sidecar, and I am pretty sure that it does not have HEVC encode/decode in hardware.  I think hardware support for HEVC encode/decode started with the 2017 iMac.
  • Reply 6 of 27
    nguyenhm16nguyenhm16 Posts: 203member
    aieronimo said:
    dempson said:
    The listed models have one feature in common: all have a Skylake or newer processor.

    Skylake adds hardware encode/decode support for HEVC, so this might just be a case of the Sidecar feature being implemented with HEVC rather than H.264 to reduce bandwidth requirements or allow a higher frame rate. Older Mac models would have to do HEVC encode in software, so enabling the workaround might impose a significant CPU performance load when the display is rapidly changing.

    I have a late 2015 iMac 27-inch, which is listed as one of the supported models for Sidecar, and I am pretty sure that it does not have HEVC encode/decode in hardware.  I think hardware support for HEVC encode/decode started with the 2017 iMac.
    According to everymac, 2015 iMacs use 5th (21.5") or 6th (27") gen CPUs, which do have Quick Sync:
    https://everymac.com/systems/apple/imac/specs/imac-core-i5-2.8-21-inch-aluminum-late-2015-specs.html
    https://ark.intel.com/content/www/us/en/ark/products/87714/intel-core-i5-5575r-processor-4m-cache-up-to-3-30-ghz.html

    https://everymac.com/systems/apple/imac/specs/imac-core-i5-3.2-27-inch-aluminum-retina-5k-late-2015-specs.html
    https://ark.intel.com/content/www/us/en/ark/products/88184/intel-core-i5-6500-processor-6m-cache-up-to-3-60-ghz.html

    racerhomie3toysandme
  • Reply 7 of 27
    Cesar Battistini MazieroCesar Battistini Maziero Posts: 339member
    dempson said:
    The listed models have one feature in common: all have a Skylake or newer processor.

    Skylake adds hardware encode/decode support for HEVC, so this might just be a case of the Sidecar feature being implemented with HEVC rather than H.264 to reduce bandwidth requirements or allow a higher frame rate. Older Mac models would have to do HEVC encode in software, so enabling the workaround might impose a significant CPU performance load when the display is rapidly changing.

    If I'm right, this could impose a similar requirement on the receiving iPad: basic HEVC hardware decode is a feature of the A9 and later processors, so A8 models that can run iOS 13 (iPad Air 2 and iPad mini 4) may be unable to act as a sidecar receiver as they would have to decode the video stream in software.

    There was a similar cutoff with the introduction of AirPlay video support: it required a Sandy Bridge or later processor to get H.264 hardware encode support. Third party software (AirParrot) implemented that feature on older Macs by doing the H.264 encode in software, but it caused a fair amount of CPU overhead.
    You are correct, it always has a reason, Apple is not a mean company trying to make you buy new stuff, if the performance is not going to be ideal, they won't support it.

    A lot of windows features are available to older machines, but run so badly, they become unusable.
    racerhomie3chiatoysandmecaladanianfastasleepStrangeDayschasm
  • Reply 8 of 27
    SoliSoli Posts: 10,035member
    saarek said:
    I remember how I couldn’t get AirPlay to work on my 2010 iMac, but the knockoff application called AirParrot handled the task with ease.

    There won’t be a real technical reason, just Apple trying to push people to newer machines.
    That's not why 3rd-party applications exist. Apple supporting certain features isn't some circuitous move to force you to buy new HW.

    Think about the foolishness of Apple actively supporting old HW going back 4 years with their iPhone but then not including some features that they can't get to work well in all cases for the oldest hardware. If they really wanted to force users into new HW they would limit their OS updates to 3 or 2 or even 1 year old devices, which would be on par with Android.

    Do you think Apple is really that stupid to not realize that offering OS updates to old devices will help keep users on old devices?
    edited June 2019 racerhomie3chiafastasleepStrangeDayschasm
  • Reply 9 of 27
    dempsondempson Posts: 62member
    aieronimo said:
    I have a late 2015 iMac 27-inch, which is listed as one of the supported models for Sidecar, and I am pretty sure that it does not have HEVC encode/decode in hardware.  I think hardware support for HEVC encode/decode started with the 2017 iMac.
    According to Apple's WWDC 2017 introduction of HEVC/HEIF, 8-bit HEVC hardware decode and encode support on a Mac requires a 6th generation or later Intel processor (i.e. Skylake or later). The Late 2015 27-inch Retina 5K iMac has a Skylake processor so should support 8-bit HEVC.

    Skylake does not have hardware decode support for 10-bit HEVC. That was added in Kaby Lake (7th generation), which includes 2017 iMacs.

    As of WWDC 2017 (therefore High Sierra), no Macs were going to use hardware support for 10-bit HEVC encode, but it appears Kaby Lake also added that feature.

    Given the Skylake processor requirement, that probably means Sidecar is using 8-bit HEVC. In theory it could step up to 10-bit HEVC if the Mac and iPad are new enough.
    macgui
  • Reply 10 of 27
    SoliSoli Posts: 10,035member
    This isn't only commonplace, it's expected and par for the course. They can still compete well by offering features that aren't available with the built-in version.

    We also see this go the other way (or un-Sherlocked), as is the case with Back to My Mac pushing many to 3rd-party solutions.
  • Reply 11 of 27
    dempsondempson Posts: 62member

    nguyenhm16 said:
    According to everymac, 2015 iMacs use 5th (21.5") or 6th (27") gen CPUs, which do have Quick Sync:
    The first version of Quick Sync was introduced in Sandy Bridge (2nd gen Core i3/i5/i7), initially supporting H.264, so some variant of Quick Sync exists in almost all 2011-2012 Macs (apart from the 2012 Mac Pro) and all 2013 and later Macs.

    Later processor generations improved Quick Sync and added more video formats. 5th gen (Broadwell) added some VP8 support. 6th gen (Skylake) added 8-bit HEVC encode/decode. The 2015 21.5-inch iMac (5th gen) is excluded from the list of supported models, but the 2015 27-inch iMac (6th gen) is included so Quick Sync in Broadwell does not suffice, implying 8-bit HEVC encode/decode is the required feature.
    Solinguyenhm16macguimbenz1962
  • Reply 12 of 27
    andycandyc Posts: 7member
    So, could we use a Mac mini with iPad and no monitor?
    Solicaladaniandtb200
  • Reply 13 of 27
    SoliSoli Posts: 10,035member
    andyc said:
    So, could we use a Mac mini with iPad and no monitor?
    I like that idea!
    caladanianStrangeDaysdtb200
  • Reply 14 of 27
    macguimacgui Posts: 2,358member
    Soli said:
    andyc said:
    So, could we use a Mac mini with iPad and no monitor?
    I like that idea!
    So do I! It makes a headless Mac or mini a much more practical idea, and gives new life so some unused hardware lying around.
    StrangeDaysdtb200
  • Reply 15 of 27
    macguimacgui Posts: 2,358member

    ivanh said:
    It’s predictable and seemingly planned, like airdrop. Why giving you something new as free lunch?  That’s why Apple has to split into hardware, software and services individuals. 
    You can always count on a list of Apple gear that will make the cut for new tech and/or features to bring out the cynics/haters to play the Greedy Apple card. They're also the same trolls to lambast anybody who demonstrates factual examples to the contrary and call them fanboys or ::shudder:: fanbois! LOL

    And the instant some new feature doesn't work 100% for 100% of the time for 100% of their customers, it become a FAIL! and a -gate. So it makes sense, to anybody with a room temperature or better IQ that Apple would limit a feature to hard where that will support it, and support it well.

    At some point, you have to know when to say 'no'. Just because a feature might work on a older Mac, albeit at 70%, doesn't mean it should.

    But sure, it's a horrible, greedy business model to keep making better hardware, and developing newer software to take advantage of it. That sounds downright evil.
  • Reply 16 of 27
    MacProMacPro Posts: 19,727member
    I am amazed Steam for macOS is not complaint yet. Overall I was surprised how few of my applications were not Catalina ready including some quite old ones.  I'll miss TextWrangler although BareBones already have BBEdit I know.
  • Reply 17 of 27
    MacProMacPro Posts: 19,727member
    andyc said:
    So, could we use a Mac mini with iPad and no monitor?
    Cool although I use Apple RDT or MS RDT tech, my Mac minis have always been headless.
  • Reply 18 of 27
    fastasleepfastasleep Posts: 6,417member
    MacPro said:
    I am amazed Steam for macOS is not complaint yet. Overall I was surprised how few of my applications were not Catalina ready including some quite old ones.  I'll miss TextWrangler although BareBones already have BBEdit I know.
    I’m less concerned about Steam than I am the number of 32 bit Steam games I have. 
  • Reply 19 of 27
    StrangeDaysStrangeDays Posts: 12,877member
    ivanh said:
    It’s predictable and seemingly planned, like airdrop. Why giving you something new as free lunch?  That’s why Apple has to split into hardware, software and services individuals. 
    Tinfoil hat conspiracy nonsense. As almost every one of these hardware requirements has been explained and shown, it's about the minimum hardware required for a high-quality experience. They won't ship it with a janky solution on some machines. 
    shark5150
  • Reply 20 of 27
    StrangeDaysStrangeDays Posts: 12,877member

    macgui said:
    Soli said:
    andyc said:
    So, could we use a Mac mini with iPad and no monitor?
    I like that idea!
    So do I! It makes a headless Mac or mini a much more practical idea, and gives new life so some unused hardware lying around.
    Definitely! Currently using TeamViewer to remote into my headless Mini but would like to try it in SideCar and ditch the third-party...
    dtb200
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