Disclaimer: This is an explanation rather than a question. After reading so many posts complaining about the lack of airplay mirroring on unsupported hardware, I feel if I am going to vent about it here, I should at least do it constructively.
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Airplay mirroring is different from airplay. With airplay, videos and music are streamed from one device to the appleTV. This is a very simple process. It's basically just moving data. The only bottleneck is the network.
Airplay mirroring is much more involved. With mirroring, there is no pre-processed file ready to stream to the appleTV. Therefore, the Mac/iPad needs to record what is on the screen and send it to the AppleTV in a format that it understands. This means it must encode. There are 2 different methods of encoding.
Software encoding will run on just about anything. Being software based, tweaks and improvements can be made at any time. It is this flexibility that makes it so appealing and why hardware-based encoding is not used more often. However, it is inefficient, as anyone who has run handbrake before can tell you.
Hardware based encoding is very inflexible. It has set parameters and after release, cannot be tweaked. However, it is able to work much smarter than a software encode. The entire process is streamlined. This makes it work faster while using less power, producing less heat, and placing a lesser strain on your mac.
Since you need to be able to use the mac while this is running, hardware was the way to go. However, there wasn't a practical way to do this yet. Some GPUs could theoretically achieve this, but the implementation varied widely from chip to chip.
Remember airplay mirroring in iOS? An iPad is able to do all of this without breaking a sweat. This is a perfect example of hardware accelerated encoding. It doesn't need to be flexible because it has a very specific purpose. It just needs to be as efficient as possible. On the iPad, encoding is done with the A5 chip, but full-fleged OSX computers don't have that. Enter intel quick-sync!
The same concept that allows the ipad to mirror to the appletv is being used here. Quick-sync is a technology developed by intel specifically to encode videos into h.264 in hardware. Again, work smarter, not harder.
Quick-sync was first used in the intel sandy-bridge processors, and carried over to ivy-bridge. Before this, quick-sync DID NOT EXIST. It is a special function built into the CPU itself and cannot be added to past equipment.
While the same thing could be achieved in software on older hardware (with products like airparrot) system performance would be compromised. Doing the exact same thing in software is ALWAYS more complex than doing it in hardware. It's like a Rube-Goldberg machine.
The reason some of the previous generation apple products do not support airplay mirroring is because they lack quick-sync, and apple isn't about to create a crappy plan-b for older machines to struggle with. If it can't be done well, apple typically doesn't do it at all.
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Airplay mirroring is different from airplay. With airplay, videos and music are streamed from one device to the appleTV. This is a very simple process. It's basically just moving data. The only bottleneck is the network.
Airplay mirroring is much more involved. With mirroring, there is no pre-processed file ready to stream to the appleTV. Therefore, the Mac/iPad needs to record what is on the screen and send it to the AppleTV in a format that it understands. This means it must encode. There are 2 different methods of encoding.
Software encoding will run on just about anything. Being software based, tweaks and improvements can be made at any time. It is this flexibility that makes it so appealing and why hardware-based encoding is not used more often. However, it is inefficient, as anyone who has run handbrake before can tell you.
Hardware based encoding is very inflexible. It has set parameters and after release, cannot be tweaked. However, it is able to work much smarter than a software encode. The entire process is streamlined. This makes it work faster while using less power, producing less heat, and placing a lesser strain on your mac.
Since you need to be able to use the mac while this is running, hardware was the way to go. However, there wasn't a practical way to do this yet. Some GPUs could theoretically achieve this, but the implementation varied widely from chip to chip.
Remember airplay mirroring in iOS? An iPad is able to do all of this without breaking a sweat. This is a perfect example of hardware accelerated encoding. It doesn't need to be flexible because it has a very specific purpose. It just needs to be as efficient as possible. On the iPad, encoding is done with the A5 chip, but full-fleged OSX computers don't have that. Enter intel quick-sync!
The same concept that allows the ipad to mirror to the appletv is being used here. Quick-sync is a technology developed by intel specifically to encode videos into h.264 in hardware. Again, work smarter, not harder.
Quick-sync was first used in the intel sandy-bridge processors, and carried over to ivy-bridge. Before this, quick-sync DID NOT EXIST. It is a special function built into the CPU itself and cannot be added to past equipment.
While the same thing could be achieved in software on older hardware (with products like airparrot) system performance would be compromised. Doing the exact same thing in software is ALWAYS more complex than doing it in hardware. It's like a Rube-Goldberg machine.
The reason some of the previous generation apple products do not support airplay mirroring is because they lack quick-sync, and apple isn't about to create a crappy plan-b for older machines to struggle with. If it can't be done well, apple typically doesn't do it at all.
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