Byte array to buffered image conversion slow
bufferedimage, bytearrayinputstream, java, javax.imageio
Solution
I think the problem might be related to the fact that ImageIO by default uses disk caching (to a temp file), even if your source is a `ByteArrayInputStream`. So if your file system is slow, reading will also be slow, regardless of input source.
You can disable the disk caching (at the cost of using more memory) with `ImageIO.setUseCache(false)`. This will still cache your streams (to allow backwards seeking), but only in memory.
It's also possible to set the cache directory to a specific path using `ImageIO.setCacheDirectory(cacheDirectory)`, if you have a faster disk/ramdisk or similar to store your temp files.
That said, your reported read times seems unreasonably high, even for disk cached reads. If the problem persists, I suggest using a profiler to find out where the time is spent, and look at possible optimizations.
PS: I also have a custom `ByteArrayImageInputStream` that might help reduce both disk access and memory consumption, should this really be the problem.
Problem
I have a simple server-side code that receives a byte array representing an image in JPEG format and returns the dimensions of the image. ``` public String processImage(byte[] data) { long startTime = System.currentTimeMillis(); ByteArrayInputStream stream = new ByteArrayInputStream(data); BufferedImage bufferedImage; bufferedImage = ImageIO.read(stream); int height = bufferedImage.getHeight(); int width = bufferedImage.getWidth(); long endTime = System.currentTimeMillis(); return "height="+height+" | width="+width+" | elapsed="+(endTime-startTime); } ``` It works, but the problem is it's unacceptably slow. For an image that's 100KB, it's taking 6s. For an image that's 900KB, it's taking 30s. Is that expected? Is there a way to make byte array to bufferedImage conversion faster? FYI, grabbing height/width isn't the only thing I intend to do. I eventually want to process the bufferedImage. So getting height/width was just an example code.