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Apple Watch is encoding each frame as PNG

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11–20 of 35 posts

Re: Apple Watch is encoding each frame as PNG

#11
> When Apple realizes how to avoid that, the watch will last for a week instead of hours.

In order for this statement to be true, the CPU would have to be using 85% of the entire watch's power consumption just to shuffle PNGs. I bet the entire CPU doesn't use nearly that much power, once you include the display.

Re: Apple Watch is encoding each frame as PNG

#12
post #7

The big take-away: In the end of the day, the watch battery is there just to shuffle these .PNGs around. When Apple realizes how to avoid that, the watch will last for a week instead of hours.

This is ridiculous. Even if you don't use the screen the watch still only lasts less than 2 days.

Re: Apple Watch is encoding each frame as PNG

#13
post #6

PNG is not cheap on the compression side, due to the lossless coder. It's a little better to decompress: Some benchmarks on iPhone 6 are here: https://browser.primatelabs.com/geekbench3/4423501 e.g., JPEG is 15x faster to compress and 2.5x faster to decompress.

You can always adjust the compression settings on a PNG to make compression faster.

Re: Apple Watch is encoding each frame as PNG

#14
post #7

The big take-away: In the end of the day, the watch battery is there just to shuffle these .PNGs around. When Apple realizes how to avoid that, the watch will last for a week instead of hours.

Except Android Wear watches are built essentially identically, and only get about a days worth of life, and don't do any of this crazy shit.

Yeah. Pebble does get a week of battery life, however. The distinction between them and AppleWatch/AndroidWear is that the Pebble uses an E-ink screen that consumes no power when it doesn't change. That makes me think that the display is the biggest power drain on a smartwatch.

Re: Apple Watch is encoding each frame as PNG

#15
> Constants are defined via let, and variable are allowed to vary through a var. Though constants are lame, as only the binding itself is constant and you can change everything inside them as usual.

That is at best misleading, as it is not true for collections. From the Swift docs:

> If you create an array, a set, or a dictionary, and assign it to a variable, the collection that is created will be mutable. This means that you can change (or mutate) the collection after it is created by adding, removing, or changing items in the collection. If you assign an array, a set, or a dictionary to a constant, that collection is immutable, and its size and contents cannot be changed.

Swift is the only language that I've seen that actually does make a distinction depending on the keyword used.

Re: Apple Watch is encoding each frame as PNG

#16
post #9

I never understand how someone can write an article about their very first foray into something and then, at the end, assert that they know more than the experts already. > In the end of the day, the watch battery is there just to shuffle these .PNGs around. When Apple realizes how to avoid that, the watch will last for a week instead of hours. Drawing every frame using CoreGraphics is a terrible idea, on any iOS dev…

I too was expecting a technical article from an expert, so I closed it after reading the first sentence. While reading the first sentence, a Flash plugin on the page crashed my browser, making the author even less credible of an authority on performance benchmarking.

Re: Apple Watch is encoding each frame as PNG

#17
post #7

The big take-away: In the end of the day, the watch battery is there just to shuffle these .PNGs around. When Apple realizes how to avoid that, the watch will last for a week instead of hours.

Except he provides no evidence this is true, and in fact, it's almost certainly 100% not true ;-)

Hint: the power draw on these watches is not from drawing.

On phones, with powerful CPU's, the display is usually 10x the draw of the CPU (depends on the CPU).

On a watch, what do you think that ratio is?

Re: Apple Watch is encoding each frame as PNG

#18
post #7

The big take-away: In the end of the day, the watch battery is there just to shuffle these .PNGs around. When Apple realizes how to avoid that, the watch will last for a week instead of hours.

Except he provides no evidence this is true, and in fact, it's almost certainly 100% not true ;-) Hint: the power draw on these watches is not from drawing. On phones, with powerful CPU's, the display is usually 10x the draw of the CPU (depends on the CPU). On a watch, what do you think that ratio is?

I have this weird feeling his statement might have been a joke, rather than to be taken literally as an engineering calculation.

Nawh, I'm probably wrong.

Re: Apple Watch is encoding each frame as PNG

#19
post #9

I never understand how someone can write an article about their very first foray into something and then, at the end, assert that they know more than the experts already. > In the end of the day, the watch battery is there just to shuffle these .PNGs around. When Apple realizes how to avoid that, the watch will last for a week instead of hours. Drawing every frame using CoreGraphics is a terrible idea, on any iOS dev…

I too was expecting a technical article from an expert, so I closed it after reading the first sentence. While reading the first sentence, a Flash plugin on the page crashed my browser, making the author even less credible of an authority on performance benchmarking.

It is a hosted blogging service and author has no power over what they do with the flash

Re: Apple Watch is encoding each frame as PNG

#20

Earlier quoted context omitted.

Except Android Wear watches are built essentially identically, and only get about a days worth of life, and don't do any of this crazy shit.

Yeah. Pebble does get a week of battery life, however. The distinction between them and AppleWatch/AndroidWear is that the Pebble uses an E-ink screen that consumes no power when it doesn't change. That makes me think that the display is the biggest power drain on a smartwatch.

It's not E-ink, it's a transflextive LCD
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