Apple Watch is encoding each frame as PNG

#1

Post by vzaliva » Sat, Dec 05, 2015, 5:35 PM UTC

Apple Watch is encoding each frame as PNG
lionet.livejournal.com

Re: Apple Watch is encoding each frame as PNG

#2

Post by Trisell » Sat, Dec 05, 2015, 6:15 PM UTC

I think I'm more impressed that LiveJournal is still around 10 years after it first came out.

Re: Apple Watch is encoding each frame as PNG

#3

Post by colinramsay » Sat, Dec 05, 2015, 6:26 PM UTC

Trisell wrote: post #2

I think I'm more impressed that LiveJournal is still around 10 years after it first came out.

LiveJournal is older than that; it was launched in 1999.

Re: Apple Watch is encoding each frame as PNG

#4

Post by kiddico » Sat, Dec 05, 2015, 6:28 PM UTC

Trisell wrote: post #2

I think I'm more impressed that LiveJournal is still around 10 years after it first came out.

It's the small accomplishments I appreciate.

Re: Apple Watch is encoding each frame as PNG

#5

Post by thought_alarm » Sat, Dec 05, 2015, 6:30 PM UTC

Trisell wrote: post #2

I think I'm more impressed that LiveJournal is still around 10 years after it first came out.

10 years after it died, you mean.

Re: Apple Watch is encoding each frame as PNG

#6

Post by herf » Sat, Dec 05, 2015, 6:32 PM UTC

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.

Re: Apple Watch is encoding each frame as PNG

#7

Post by donohoe » Sat, Dec 05, 2015, 6:35 PM UTC

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.

Re: Apple Watch is encoding each frame as PNG

#8

Post by dilap » Sat, Dec 05, 2015, 6:36 PM UTC

This is for 3rd party apps -- despite the "native" 2.0 SDK, where all your code runs on the watch, it's still split clumsily into app (which you can only control by providing interface templates) and extension, which is where your code runs. The extension can control the app only through a very limited SDK that has to do IPC to effect changes in the main app.

Apple's own apps don't have this restriction, and I can't see a good one for 3rd party apps to have it, either -- hopefully they'll open up a full API in the future.

Re: Apple Watch is encoding each frame as PNG

#9

Post by mrshoe » Sat, Dec 05, 2015, 6:38 PM UTC

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 device. Just like any platform, you have to understand at least the basics of the underlying architecture if you want to write efficient code.

I happened to make the built-in Stopwatch app on the watch, which displays an animated graph very similar to his. Suffice it to say, I did not use a CADisplayLink and CoreGraphics at 60fps. Especially considering my graph is horizontally scrollable by the user.

Even if WatchKit still doesn't provide a more efficient way to do this (I don't know; I've never used WatchKit), rest assured that Apple's apps certainly don't use this method, so the week-long battery life claim is just a dream, unfortunately.

Re: Apple Watch is encoding each frame as PNG

#10

Post by DiabloD3 » Sat, Dec 05, 2015, 6:41 PM UTC

donohoe wrote: 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.