How to limit memory usage by libjpeg - ios

Short version: iOS's UIImageJPEGRepresentation() crashes on large images. I'm trying to use & modify libjpeg to respect the max_memory_to_use field, which it's ignoring.
Long version: I'm writing an iOS app which crashes when converting a large image to JPEG after prolonged usage reduces available memory (a trickling leak involving quirks of #autoreleasepool{}, but we're addressing that separately). For images captured by the device camera (normal use, actual size) UIImageJPEGRepresentation() can require up to 200MB (!), crashing if not available. This is a problem with UIImageJPEGRepresentation() which a web search shows goes back for years and seems unsolved; filing a tech support request with Apple elicits "file a bug report" which doesn't solve my immediate customer needs.
To resolve this, I'm bypassing UIImageJPEGRepresentation() by using libjpeg (http://www.ijg.org) and digging into its operation, which shows exactly the same problem (presumably Apple uses it in iOS). libjpeg does provide a means to specify maximum memory usage via the parameter max_memory_to_use a la:
struct jpeg_compress_struct cinco;
cinfo.mem->max_memory_to_use = 10*1024*1024;
which would be used by the libjpeg function jpeg_mem_available (j_common_ptr cinfo, long min_bytes_needed, long max_bytes_needed, long already_allocated) (in jmemnobs.c) but, in the standard implementation, is completely ignored (comment even says Here we always say, "we got all you want bud!"). Blender has altered the function (http://download.blender.org/source/chest/blender_2.03_tree/jpeg/jmemmac.c) to respect the parameter, but seems I'm missing something to make it work in my app or it's just being ignored anyway elsewhere.
So: how does one modify jmemnobs.c in libjpeg to actually & seriously respect memory limitations, rather than jokingly ignore them?

Related

Some gif are taking too much memory

I know it's a very common problem and this link is clearly explained because this happens.
It struck me a lot that react-native-flanimatedimage exists, since, it seems that it solved the problem using FLAnimatedImage which is a very famous module for native IOS.
The truth is that the module fulfills what it promises, but in exchange for conserving memory, completely destroys the animation of the gif, causing it to be seen in slow motion.
Even within the issues of the module many people report this same
https://github.com/Flipboard/FLAnimatedImage/issues?utf8=%E2%9C%93&q=slow
The problem is that some solutions that I have tried do not work or are simply solutions for native IOS workers.
The gif that I am trying to load, increases about 300mb the memory of the device, for each time that i render the gif and in some cases and depending on the device, this is causing a memory crash.
I'm not sure what the clean way to attack this problem is. Release the memory in some way, or if you continue on the path of trying to avoid that the memory is loaded so much, using FLAnimatedImage or some other tool that you can recommend me.

LZMA SDK iOS to show progress

If anyone has used the iOS wrapper for the LZMA SDK available at https://github.com/mdejong/lzmaSDK and have been able to tweak it in order to see the progress of unarchiving, please help.
I am going to use this SDK in iOS to extract a 16MB file, which uncompresses to a 150MB file, and this takes around 40seconds to complete. It would be good to have some kind of callback for showing the progress of uncompression.
Help is greatly appreciated.
Thanks
So, I looked at this issue quite a bit recently, and honestly the best you are going to be able to do is look for all the files in a specific tmp dir where decompression is going on and then count them and compare to a known size N. The problem with attempting to do this in the library is that it spans multiple runtimes and the callback idea makes the code a mess. Also, a callback would not help that much because of the way 7z compression works. To decode, one needs to build up the decompression dictionary before specific files can be decompressed, and that process of building up the dictionary takes a long time before the first file can even be written. So, if you put a "percent done" counter in your app showing how much was done, it would show 0% done for a long time, then jump to 50% and then 90 or 100 %. Basically, it would not be that useful even if it was implemented.
You could try C++ port of the latest LZMA SDK(15.06) without described above limitations(C version). Memory allocations and IO read/write can be tuned in runtime, plus work with password encrypted archives, smoothed progress, Lzma & Lzma2 archive types etc.
GitHub: https://github.com/OlehKulykov/LzmaSDKObjC

UIImagePickerController in source type Camera with allowsEditing to YES causes a “Terminated due to memory pressure” in iOS 7? [duplicate]

I am working on an iOS app in Xcode. Earlier I got it to start and run, up to a limited level of functionality. Then there were compilation failures claiming untouched boilerplate generated code had syntax errors. Copying the source code into a new project gets a different problem.
Right now, I can compile and start running, but it states before even the launch image shows up that the application was closed due to memory pressure. The total visual assets is around 272M, which could be optimized some without hurting graphical richness, and is so far the only area of the program expected to be large. (The assets may or may not be kept in memory; for instance every current loading image is populated and my code never accesses any loading image programmatically.) And it crashes before the loading image has itself loaded.
How can I address this memory issue? I may be able to slim down the way images are handled, but I suspect there is another root cause. Or is this excessive memory consumption?
Thanks,
Review the Performance Tuning section of Apple's iOS Programming documentation. Use Apple's Instruments application to determine how, when, and how much memory your app is using.
One approach you should consider is to disconnect the graphics resources from your application, and add them back one-by-one once you feel they meet the requirements and limitations of iOS.
Now, this part of my answer is opinion: it sounds like your app is a high risk for being rejected from the App Store, in case that is your intended destination for this app.

Determining available video memory

When developing an OpenGL program, is there a way to poll from the system to find out just how many megabytes are available to store textures, etc?
Or is the standard approach these days just allocate memory and forget about everything?
Although the official stance remains "you don't need to know, you don't want to know, and it would not help you anyway", luckily at least two IHVs have shown a little more insight lately and offer extensions to query that information:
NVX_gpu_memory_info
ATI_meminfo
One nice thing about these extensions is that they have a least common denominator which is just what most people need, and you don't need to query extension support or do anything special, as they both work via glGetIntegerv.
In the easiest case, you can just initialize an array of 4 integers to zero (or some minimum default value that you'll assume in case the extensions don't work), then you call glGetIntegerv twice (with GPU_MEMORY_INFO_CURRENT_AVAILABLE_VIDMEM_NVX and TEXTURE_FREE_MEMORY_ATI, respectively), and finally call glGetError to clear the error state. glGetIntegerv does not modify the pointed-to memory if it fails, nor does it crash or any other bad thing -- it merely sets the error state to GL_INVALID_ENUM.
Both extensions return a value in the first array position, the ATI one returns some values in the other 3 too.
n.b.: glAreTexturesResident has not been supported for almost a decade on mainstream hardware, in the same manner as texture priorities. The common mantra is that the driver writer knows much better than you anyway.
OpenGL doesn't give you this information. And frankly: There's only little benefit, simply because today we have multitasking operating systems. The OpenGL driver is responsible for swapping in texture data to/from system memory, if there's demand for it.
What OpenGL can do for you, is tell, if the textures you've uploaded are still resident in fast memory. The function is called "glAreTexturesResident". You can use this to gradually upload stuff to the GPU until you've filled up the GPU's memory. But keep in mind that you're not the only user of the GPU.

Hunting down EOutOfResources

Question:
Is there an easy way to get a list of types of resources that leak in a running application? IOW by connecting to an application ?
I know memproof can do it, but it slows down so much that the application won't even last a minute. Most taskmanager likes can show the number, but not the type.
It is not a problem that the check itself is catastrophic (halts the app process), since I can check with a taskmgr if I'm getting close (or at least I hope)
Any other insights on resource leak hunting (so not memory) is also welcomed.
Background:
I've an Delphi 7/2006/2009 app (compiles with all three) and after about a few week it starts acting funny. However only on one of the places it runs, on several other systems it runs till the power goes out.
I've tried to put in some debug code to narrow the problem down. and found out that the exception is EOutofResources on a save of a file. (the file save can happen thousands of times a day).
I have tried to reason out memory leaks (with fastmm), but since the dataflow is quite high (60MByte/s from gigabit industrial camera's), I can only rule out "creeping" memory leaks with fastmm, not quick flashes of memoryleaks that exhaust memory around the time it happens. If something goes wrong, the app fills memory in under half a minute.,
Main suspects are filehandles that are somehow left on some error and TMetafiles (which are streamed to these files). Minor suspects are VST, popupmenu and tframes
Updates:
Another possible tip: It ran fine for two years with D7, and now the problems are with Turbo Explorer (which I use for stable projects not converted to D2009 ).
Paul-Jan: Since it only happens once a week (and that can happen at night), information acquisition is slow. Which is why I ask this question, need to combine stuff for when I'm there thursday. In short: no I don't know 100% sure. I intend to bring the entire Systemtools collection to see if I can find something (because then it will be running for days). There is also a chance that I see open files. (maybe should try to find some mingw lsof and schedule it)
But the app sees very little GUI action (it is an machine vision inspection app), except screen refresh +/- 15/s which is tbitmap stretchdraw + tmetafile, but I get this error when saving to disk (TFileStream) handles are probably really exhausted. However in the same stream, TMetafile is also savetostreamed, something which later apps don't have anymore, and they can run from months.
------------------- UPDATE
I've searched and searched and searched, and managed to reproduce the problems in-vitro two or three times. The problems happened when memusage was +/- 256MB (the systems have 2GB), user objects 200, gdi objects 500, not one file more open than expected ).
This is not really exceptional. I do notice that I leak small amounts of handles, probably due to reparenting frames (something in the VCL seems to leak HPalette's), but I suspect the core cause is a different problem. I reuse TMetafile, and .clear it inbetween. I think clearing the metafile doesn't really (always?) resize the resource, eventually each metafile in the entire pool of tmetafile at maximum size, and with 20-40+ tmetafiles (which can be several 100ks each) this will hit the desktop heap limit.
That's theory, but I'll try to verify this by setting the desktop limit to 10MB at the customers, but it will be several weeks before I have confirmation if this changes anything. This theory also confirms why this machine is special (it's possible that this machine naturally has slightly larger metafiles on average). Occasionally freeing and recreating a tmetafile in the pool might also help.
Luckily all these problems (both tmetafile and reparenting) have already been designed out in newer generations of the apps.
Due to the special circumstances (and the fact that I have very limited test windows), this is going to be a while, but I decided to accept the desktop heap as an example for now (though the GDILeaks stuff was also somewhat useful).
Another thing that the audit revealed GDI-types usage in a thread (though only saving tmetafiles (that weren't used or connected otherwise) to streams.
------------- Update 2.
Increasing the desktop limit only seemed to minorly increase the time till the problem occurred.
Unfortunately, I won't be able to follow up on this further, since the machines were updated to a newer version of the framework that doesn't have the problem.
In summary I can only state what the three core modifications were going from the old to the new framework:
I no longer change screens by reparenting frames. I now work with forms that I hide and show. I changed this since I also had very rare crashes or exceptions (that could be clicked away) due to this. The crashes were all while operating the GUI though, not spontaneously like the main problem
The routine where the crash happened dealt with TMetafile. TMetafile has been designed out, and replace by a simpler own made format. (basically arrays with Opengl vertices)
Drawing no longer happened with tbitmap with a tmetafile overlay strechdrawn over it, but using OpenGL.
Of course it could be something else too, that got changed in the rewrite of the above parts, fixing some very nasty detail bug. It would have to be an extremely bad one, since I analysed the above system as much as I could.
Updated nov 2012 after some private mail discussion: In retrospect, the next step would have been adding a counter to the metafiles objects, and simply reinstantiate them every x * 1000 uses or so, and see if that changes anything. If you have similar problems, try to see if you can somewhat regularly destroy and reinitialize long living resources that are dynamically allocated.
There is a slim chance that the error is misleading. The VCL naively reports EOutOfResources if it is unable to obtain a DC for a window (see TWinControl.GetDeviceContext in Controls.pas).
I say "naively" because there are other reasons why GetDC() might return a NULL handle and the VCL should report the OS error, not assume an out of resources condition (there is a Windows version check required for this to be reliably possible, but the VCL could and should take of that too).
I had a situation where I was getting the EOutOfResources error as the result of a window handle becoming invalid. Once I'd discovered the true problem, finding the cause and fixing it was simple, but I wasted many, many hours trying to find a non-existent resource leak.
If possible I would examine the stack trace leading to this exception - if it is coming from TWinControl.GetDeviceContext then the problem may not be what you think (it's impossible to say what it might be of course, but eliminating the impossible is always the first step toward discovering the solution, no matter how improbable).
If they are GDI handle leaks you can have a look at MSDN Magazine January 2003 which uses the tool GDILeaks. Other tools are GDIObj or GDIView. Also see here.
Another source of EOutOfResources could be that the Desktop Heap is full. I've had that issue on busy terminal servers with large screens.
If there are lots of file handles you are leaking you could check out Process Explorer and have a look at the open file handles of your process and see any out of the ordinary. Or use WinDbg with the !htrace command.
I've run into this problem before. From what I've been able to tell, Delphi may throw an EOutOfResources any time the Windows API returns ERROR_NOT_ENOUGH_MEMORY, and (as the other answers here discuss) Windows may return ERROR_NOT_ENOUGH_MEMORY for a variety of conditions.
In my case, EOutOfResources was being caused by a TBitmap - in particular, TBitmap's call to CreateCompatibleBitmap, which it uses with its default PixelFormat of pfDevice. Apparently Windows may enforce fairly strict systemwide limits on the memory available for device-dependent bitmaps (see, e.g, this discussion), even if your system otherwise has plenty of memory and plenty of GDI resources. (These systemwide limits are apparently because Windows may allocate device-dependent bitmaps in the video card's memory.)
The solution is simply to use device-independent bitmaps (DIBs) instead (although these may not offer quite as good of a performance). To do this in Delphi, set TBitmap.PixelFormat to anything other than pfDevice. This KB article describes how to pick the optimal DIB format for a device, although I generally just use pf32Bit instead of trying to determine the optimal format for each of the monitors the application is displayed on.
Most of the times I saw EOutOfResources, it was some sort of handle leak.
Did you try something like MadExcept?
--jeroen
"I've tried to put in some debug code to narrow the problem down. and found out that the exception is EOutofResources on a save of a file. (the file save can happen thousands of times a day)."
I'm shooting in the dark here, but could it be that you're using the Windows API to (GetTempFileName) create a temp file and you're blowing out some file system indexes or forgetting to close a file handle?
Either way, I do agree that with your supposition about it being a file handle problem. That seems to be the most likely thing given your symptoms and diagnosis.
Also try to check handle count for the application with Process Explorer from SysInternals. Handle leaks can be very dangerous and they build slowly through time.
I am currently having this problem, in software that is clearly not leaking any handles in my own code, so if there are leaks they could be happening in a component's source code or the VCL sourcecode itself.
The handle count and GDI and user object counts are not increasing, nor is anything being created. Deltic's answer shows corner cases where the message is kind of a red-herring, and Allen suggests that even a file write can cause this error.
So far, The best strategy I have found for hunting them down is to use either JCL JCLDEBUG stack tracebacks, or the exception report save features in MadExcept to generate the context information to find out what is actually failing.
Secondly, AQTime contains many tools to help you, including a resource profiler that can keep the links between where the code that created the resources is, and how it was called, along with counts of the total numbers of handles. It can grab results MID RUN and so it is not limited to detecting unfreed resources after you exit. So, run AQTime, do a results capture in mid run, wait several hours, and capture again, and you should have two points in time to compare handle counts. Just in case it is the obvious thing. But as Deltics wisely points out, this exception class is raised in cases where it probably shouldn't have been.
I spent all of today chasing this issue down. I found plenty of helpful resources pointing me in the direction of GDI, with the fact that I'm using GDI+ to produce high-speed animations directly onto the main form via timer/invalidate/onpaint (animation performed in separate thread). I also have a panel in this form with some dynamically created controls for the user to make changes to the animation.
It was extremely random and spontaneous. It wouldn't break anywhere in my code, and when the error dialog appeared, the animation on the main form would continue to work. At one point, two of these errors popped up at the same time (as opposed to sequential).
I carefully observed my code and made sure I wasn't leaking any handles related to GDI. In fact, my entire application tends to keep less than 300 handles, according to Task Manager. Regardless, this error would randomly pop up. And it would always correspond with the simplest UI related action, such as just moving the mouse over a standard VCL control.
Solution
I believe I have solved it by changing the logic to performing the drawing within a custom control, rather than directly to the main form as I had been doing before. I think the fact that I was rapidly drawing on the same form canvas which shared other controls, somehow they interfered. Now that it has its own dedicated canvas to draw on, it seems to be perfectly fixed.
That is with about 1 hour of vigorous testing at least.
[Fingers crossed]

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