Why does my iOS app compress so well? - ios

I'm baffled by how Xcode is managing to compress my iOS app so effectively. All of my images and sound files combined add up to 282 MB for about 3000 items. However, the .app is somehow only 126 MB! Further, the file sizes inside the .app package contents are the same, yet the folder sizes are all roughly half size. How is this possible?

The main reason is probably that all your images (assuming images make up the majority of the 282 MBs in your app) are compressed using pngcrush as a build step in your application. You can actually watch this by looking at at the build log from xcode.
The special version of pngcrush that is used in the iOS SDK cause the PNG images to be non-standard (making them unviewable on the Mac or any other standard program for that matter). Instead, they are adapted to the display hardware of the iOS devices which means that they will load faster as well.

Related

".ipa" file size issues -xcode archive

I have created an project of size nearly 5 MB, but after archiving app from xworkspace it increases upto 194Mb and IPA file size upto 70 MB.
Will it fine to have a large size "ipa" for normal application ?
Thank you
It is fine as long as the IPA file size is less than 100 MB. Once the file size becomes larger than 100MB, then it won't be available to download from the Appstore on Cellular Internet. It will be available to download only on WiFi.
I would recommend you inspect the Xcode project to find large dependencies that are causing the file size to increase.
If your entire project is only 5Mb size, you may have a dependency or copy build path resources problem.
Double check :
do you need all frameworks linked to the project ?
do you have a build phase which copy to final resources path unused or unwanted files ?
if you use dependency manager suche as cocoapod or carthage: are all the pulled external frameworks necessary ?
If you want to know what are the big files, it's pretty easy once you have the IPA file: rename your ipa with "zip" extension, unarchive, explore
Bonus: Even the finder say to you "XX MB", it's not the final size. To know the final size, you can upload your ipa on ituneconnect, even if you don't want to use it. after processing, in builds list. You can have the final size for each devices. ex:
As you can see Universal is quite big compared to the specific build for, for ex, iphone 6 !

Xcode Archive Is Too Large

I have a Unity3D project that I've already released for iOS via Xcode. Previously the archive size was about 30-40Mb which I'm happy with.
I've now changed a few things within the Unity project, and rebuilt it for Xcode. Now when I archive it, the size is around 110Mb, which is huge compared to the previous file size. I only changed the logo, and splash screen design.
Also, when I rebuild the older version, the size isn't 30-40Mb anymore, it's 110Mb too!
So I'm guessing this is something to do with the new Xcode for iOS8? Not 100% sure, hence why Im asking.
Thanks.
Try to turn off BitCode. Open XCode => Build Settings => search Enable BitCode. Set it to No.
Have you read this?
http://docs.unity3d.com/Manual/iphone-playerSizeOptimization.html
Also it can be fault of stripping level, try to use micro mscorlib.
In addition you can take a look at Decrease Your App’s Code Size from Mac App Programming Guide.
https://developer.apple.com/library/mac/documentation/General/Conceptual/MOSXAppProgrammingGuide/Performance/Performance.html#//apple_ref/doc/uid/TP40010543-CH9-SW2
I believe part of what is happening here is the additional overhead for the arm64 slice (unless you were already including the arm64 slice previously). I would not expect that much of an increase in size for the arm64, but it would still be roughly X2 on the app binary (minus the resources).
As of Feb 1, Apple requires arm64 support as well as the app being built with the iOS 8 SDK. The default Xcode build setting enables arm64.
What you can do is Show Package Contents on the xarchive and work your way to the app executable binary. You can then compare the size difference on the app executable binary from before and now. You can also run lipo -info on it to see all the slices from before and now. Note I am assuming you have an older xarchive to compare with.
I would then probably diff the rest of the resources (use something like Araxis merge) to see the differences in the files. This will let you see what resource files changed or got added. If your diff is only the executable, then you have isolated were the size difference has come from.
The 'Estimated App Store Size' reflects the installed app size, not the download size.
I'm basing this off the following test:
(Unity app build) Estimated App Store Size: 140.8 MB, size listed in store: 33.4 MB. The splash images alone inside the package add up to 30 megs uncompressed (all my jpegs were converted to pngs) so there's no way the installed size is 33.4 MB. After install, if I go to settings -> general -> usage -> Manage Storage I see the app is 141 MB installed.
I'm not sure how to estimate the download size, which is what matters if you have an app you want to be downloaded over cellular network and needs to be under 100 MB downloaded.
I added this as a comment to the question, but I wish I had read this as an answer, so here it is.

Decrease iOS Application size to App Store

I am trying to submit an application in App Store, and I need to decrease its memory a little bit, if this is possible. I tried a method which I am gonna describe below to make my app lighter, but with not luck.
Details
I followed these steps to see what was causing this large size
Make an archive of the project
Distribute it
Save for Enterprise or Ad-Hoc Deployment
Select the .ipa file and changed the extension to .zip
Extract it, and open Payload
Show the Package Contents
Contents
I had .png files with 680 Kb (when I added those where 32 kb approximately), I deleted them and I reduced the size of application by 2 MB. There are other files that take space but not considerably, except one executable file that is taking about 90 % of the .ipa's size.
Question
Is it possible to decrease executable file's size? If not then can you give me a hint where I should look to make my app lighter in terms of size.
P.S I use third party libraries like Vuforia SDK and libraries on GitHUB
How can I reduce the size of this executable file
You cannot reduce the size of the executable inside your built app bundle. This is your code! The only ways to reduce its size are:
Cut code. Obviously you can't do that because you would exclude functionality that makes your app work.
Remove an architecture slice. You should not do that because you want to build for all possible architectures.
Having said that... I have never generated an executable inside the app bundle anywhere near this large. Maybe you are measuring / building wrong:
Make sure you are archiving. Nothing else except an archive is worth measuring.
Make sure that you are generating a Release build when you Archive.
Make sure that your Release build settings include the full compiler optimization (smallest, fastest).
Suggestion how to reduce binary size from Reducing the size of my App:
Compiler Options
Setting the Optimization Level build setting to Fastest, Smallest [-Os]; and the Strip Debug Symbols During Copy build setting to Yes (COPY_PHASE_STRIP = YES) can dramatically lower the size of your compiled binary. These settings are the default for the "Release" configuration in Xcode projects.
Assets are almost always the main culprit of large apps sizes.
If you archive your app and export the IPA you will be able to convert it so a .zip by changing the extension and then unzip and look at the contents of the package.
If you sort by file size you will see which files are the largest. Keep in mind images with transparency are larger.
Some more insight as well: http://bjango.com/articles/pngcompression/
If you're truly concerned about the internals of the executable, build with a link map. That shows sizes by segment and by symbol.
e.g.
# Sections:
# Address Size Segment Section
0x0000AB90 0x00711D30 __TEXT __text
0x0071C8C0 0x00028D34 __TEXT __symbol_stub4
0x007455F4 0x00001A58 __TEXT __stub_helper
0x0074704C 0x00057452 __TEXT __cstring
[…]
# Symbols:
# Address Size File Name
0x000122A0 0x00000020 [ 6] ___Block_byref_object_copy_
0x000122C0 0x0000001C [ 6] ___Block_byref_object_dispose_
0x00012320 0x00000028 [ 6] ___copy_helper_block_78
0x00012348 0x0000001C [ 6] ___destroy_helper_block_79
[…]
I came across an article in the web which explains the process in the following 9 points:
Ensure that you have reached the maximum level of iOS stripping, for
more info on iOS stripping, see this post.
Enabling bitcode DOES increase the size of your over-the-air download.
In our case, it was the difference between 130 and 70MB. If you wish
to turn bitcode off, you can do so in your xcode project, or using a
post build attribute such as this one.
The Launch image in your xcode project is NOT optimized. While running
something through a compression algorithm doesn’t work because Unity
decompresses and stores images without much compression in order to
decrease startup time, it does work for the launch images that are
generated by Untiy after project generation.Run all your images
through a lossless compression algorithm in order to save a few MBs
(10 in our case).
If this isn’t enough, it’s time to start looking at your asset logs.
Run your build in Unity and open the Editor log, it’s this
ridiculously small icon next to your console preferences. In our case,
they are already optimized. With a 111MB in uncompressed assets, we
were able to achieve an over-the-air size of 70MB. Go over each asset
and change the resolution to the lowest possible quality that your
users won’t notice. The best compression setting is PVRTC for iOS.
While you are at it, check out Resource Checker in order to see large
textures in-memory. Reducing the resolution on these will also
decrease build size, as well as memory consumption. Also, please use
sprite atlases – you will see the wonders this does!
Check for unused libraries in your project, or libraries that are
using far too much space for their functionality. Commands such as df
and ls -lh might come in useful here, run these in your project files
and see which files really stand out and need to be reduced in size.
Keep in mind that these individual libraries do not necessarily have
the same build effect as your textures – generally, these are compiled
for multiple architectures, and if a library is 20MB, it generally
only affects your build size by about 6MB, due to the fact that
libraries often include architecture support for i386, arm64, and arm7
in the same library
Check that the /Plugins/Android is not included in your iOS project.
See this post for more information.
Make sure you don’t have any unused scenes in your build settings.
Build your project, and check out the archive before you submit it to
iTunes Connect. You can do so by clicking “Product -> Archive”,
letting it archive, and when it’s done, “Window -> Organizer” to pop
up this interface and find the build location.
Under “Products/Applications/game.app” Run the mv command to turn your
.app into a browsable directory.In this directory you’ll be able to
see a lot of the stuff we did, and also find inspiration for more
things you can do.
Now, there are a lot more things that could result in a bigger than
expected build size, and I’m sure there are a lot more things you can
to do get below it also.
If you’d like to add to this list, or have further questions (I’m usually happy to answer questions), leave a comment below with your specific use case, and I’ll try to help!
All the best,
Pim
If you have already checked all your assets (images, audio, etc... ) just check if you need all the external libraries (3rd party libraries out of the iOS sdk) that you import in your app.

Why are PNG images larger in the iOS app bundle than in my project?

I am in the process of updating Hungry Helga (iPhone and iPad versions) for iOS 6, and all of the PNG files in my new app bundle archives are between 20 and 40 percent larger than they were in my past releases. Of course, this is putting me over the 3G download limit of 50 MB so I'd really like to figure out what's going on.
I am currently using version 4.5 of Xcode on OSX 10.7.5. If I recall correctly the previous version was built with Xcode 4.2. I tried turning on and off PNG compression in the build settings but that had no effect on the image sizes in the bundle.
To give a concrete example, my largest PNG image is 1.9 MB as a source asset. It is 2.1 MB in the old app bundle, and 2.5 MB in the new app bundle.
Did Apple change the way the PNG compressor works or is there maybe a setting that I'm missing or something?
I do not work for Apple nor do I have any inside information - however, I did poke around and have some theories. If you use terminal you can cd into the Xcode.app and find pngcrush there:
$ find . -name pngcrush
./Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/pngcrush
If you then run:
./pngcrush -?
you find some interesting tidbits:
| It was compiled with LLVM 4.2.1 Compatible Apple Clang 4.0
(tags/Apple/clang-420.0.12) and modified by Apple as indicated in the
sources.
and
-iphone (optimize for iPhone OS)
Since I too saw that some large pngs where also much larger in the bundle than the original (which I had previously crushed myself!), I wanted to see how Xcode uses pngcrush. I used an old UNIX trick:
move pngcrush to xpngcrush
create a new executable shell file that calls pngcrush with the same argument list
log the arguments into a text file in /tmp
What I found was that Apple calls pngcrush as:
pngcrush -q -iphone oldFile newFile
One can infer from this that this Apple specific feature of pngrush was designed specifically to tailor the image for iOS. I say tailor, not crush.
Does Apple really care if your png is the smallest possible file, to save the greatest amount of space? I'd argue, not really - the devices have fairly large file storage space. Do they really care if your app downloads really fast? Again, I'd argue not really, since the user is going to assume the time is related to the size of the app, and that that is under the control of the developers.
However, what the user is going to hold Apple accountable for is the launch speed. From the first tap to when the app starts doing something - people will believe that is all the speed of the device (which we developers know is not strictly true). With the new iPad3, some of the launch images are now really big, so what can be done to make loading them as fast as possible?
I don't know the answer to that question, but I can imagine that Apple decompresses the original image, then re-compresses it with settings that make loading it in the device as fast as possible.
PS:
1) I just disabled the crush option, and observed Xcode 4.5 copying my png files without modification.
2) To get your app size down, have you tried using JPEGs with a high quality setting - even 1? Such images will look very good and be much much smaller. Virtually all images in my app are JPEGs. You can experiment with Preview to do the conversions.
EDIT: it occurred to me there may be an elegant solution to this. That is, for really important images - ones that you want to appear as fast as possible - then use pngcrush with the '-iphone' flag. For others, use more standard pngcrush options.
One way to do this is to create a new image directory, and write a shell file that pre-processes every png with a real crusher or tje '-iphone' flag, putting the output in the original image folder (where Xcode can get them). Then turn off the automatic 'Crush PNG Files' option.
EDIT2: I entered a bug at bugreporter.apple.com and posted on the Xcode listserv - if you have an interest in this bookmark the question and come back when its updated.
EDIT3: someone gave me a link that explains in more detail the how and why of Apple's '-iphone' option ImageOptim
EDIT4: Apple responded to my bug report, confirming that they modify the images for easier processing by iOS, which may make them larger, by intent.
Xcode 5 now got changes in image compressions. the best and compressed way is to use asset catalogs.
If even using Xcode 5 and asset catalogs doesn't result well for your app, check the other relative post PNG optimization issue using pngcrush tool for more answers could be helpful
Using David H's script, I found that Xcode is also passing the command line parameter "-f 0" to pngcrush. The man page indicates that the "-f 0" will disable any IDAT filtering before compression which can result in a larger PNG file. Testing on my 1.9 MB example file from above confirms:
pngcrush -iphone in.png out.png gives the 2.1 MB result that I am looking for
pngcrush -iphone -f 0 in.png out.png yields the undesired 2.5 MB result
Now the questions are: Why did Apple change this? Will it break image loading in some way if I work around it? If not, is there a setting for this in Xcode or will I always have to use a script to filter out the "-f 0" argument?

app on ipad double archive size

Hi guys I have a media heavy app for the iPad and my archive is ~370mb. For what I'm doing, that isn't unreasonable. If i view the xcarchive in finder it is ~391MB, the .ipa is ~388mb, which roughly corresponds to the size of all my assets uncompressed.
So I double-checked the actual usage on my test device and it is 755 megs! This is similar to the "estimated app store" size shown in organizer.
I checked usage on several other test devices and it is the same.
I read the other posts about the organizer estimate tending to be inaccurate, but does that translate to the usage indication on the iPad itself? Shouldn't the iPad just report how much actual space is being used?
370 mb (double) of extra usage can't be anything to do with the executable not compressing, and this shouldn't be a result of PNGs being somehow expanded, I use a ton of jpegs because they are so much smaller.
And the whole compressed/uncompressed discussion feels like a red herring because if I simply get info on the uncompressed assets folder in finder, it is ... 355 mb. So I can't understand how compressing and then uncompressing a bunch of images would double their size.
My only theories are:
- The usage on the development iPad is for some reason no indication of final app size
All my jpegs are somehow being converted to PNGs inside the ipad itself ... ??? really how is that possible??
I have two video files, they could somehow be automatically converted to another format .. ??again, really?? that sounds impossible
the app has in-app purchase capability, it could be somehow allocating disk space in anticipation of future purchases?
I hate all of those theories because none of them make sense. Any of you ever run in to this before?
So write some code in your app that after launch uses nsfilemanager to walk your complete app on the device (or simulator)and tally the totals and log it. This way you will know exactly. Also recall that the file system uses discrete disk blocks of fixed size so 1 byte files actually consume more, but this is probably not your problem.
Also zipping media rarely results in space savings.
This is similar to the "estimated app store" size shown in organizer.
You can check out why by examining the contents of your archive:
Open Organizer, select Archives, select your app, right click on your archive, Show in Finder, right click on the file, Show Package Contents, open Products, open Applications, right click on your app bundle, Show Package Contents.
Also, Xcode might combine retina and non-retina images into a single multipage TIFF file. Check out this answer for more details.

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