I have an application where users can upload images.
This images are usually taken directly from cameras and in 1mb sizes or more.
May I know what is the standard way of compressing this images before saving them to database as BLOB?
The images stored in database are just for viewing, there is no requirement to edit the image.
I have read this:
Compress Image before Saving to disk in Java
But I am wondering there are more standard ways so that the system can be more maintainable.
some codes and links will be greatly appreciated +1
Related
I want to store the images and display the same on the screen using struts. Is it better to store the images in database or on the file system? I have more than 10,000 images.
Storing images in the database as objects like blob or clob is generally not recommended as this will make the database size huge. You may get poor results while processing your resultsets. The better way to do this is have the images get stored in your file system and simply use its references in the databases which is efficient. Using a hash check on the uploaded images will also help in verifying the integrity of the images if they are uploaded to the server from the clients.
File system. It turns out it's quite good at storing files.
I have REST service that allows users to upload images and then serves those images. The images are stored to a database. I'd like to do JPG optimization for these images.
There's several command line tools to do this but I'd like to do it without first saving them to disk and then running some command-line tools. I'd rather use some Java library to directly operate on a binary stream that contains the image data.
What I'm after is a treatment similar to what for example Trimage does:
Remove all EXIF metadata from the image
Losslessy (re)compressed to the highest available compression levels
Is this possible?
It is possible to remove extraneous APPn and COM markers from the data stream. You can do that without expanding and recompressing.
Each time you expand and decompress with different quantization tables, you loose data in JPEG. There is no real point in decompression.
Yes to question #1. No to question #2.
Which is faster, to recieve images as JPG from server, and save it, then show it in a ListView or what ever
OR
receive images in an XML (as encoded String) from server, then decode it, then show it in a ListView (or even save it then show it from memory)
what is the best way (regarding performance) in transfering images FROM a server TO an android device
thanks in advance
That depends on where the limitation is. If the bandwidth of your connection is very small try to transfer as few bytes as possible. However, high compression usually costs more CPU, so if CPU power is limiting you it may be better to use a lower compression.
I am not sure what you mean by "receive images in an XML". Is it some vector format like SVG? That would normally be much smaller than a raster image (especially for large sizes).
To sum up, you will need to do some experiments to find out what works best in your case.
The best way is to get the image URL from the server and then download the image using some image managing library like https://github.com/nostra13/Android-Universal-Image-Loader or google's volley. These kind of libraries highly configurable and taking care of all the aspects of managing a bitmap.
I am in the planning stage of making a database application for android phones. One of my requirements is that I be able able to provide offline access for users. I am wondering what would be the most efficient way of storing a large amount of images (around four hundred-several thousand).
Oh, the images have been pre-compressed/optimized for mobile viewing. The 50mb limit on apk for the market won't be a issue.
You have to develop simple logic.Suppose you have connection then download all images.Now you have two way to access these images while you do not have connection-----
Store all images in data base as blob(But it not feasible to store huge amount
of data to database)
Second..
Store all images in sdcard(by making a folder in it) and now store link of these
images in data base Table.Suppose you donot have connection then first fetch
image path from DB Table then fetch file from sdcard and display
I would suggest storing the image files in sdcard and filename/path in sqlite DB. Store files in /Android/data/your.package.name/cache/ directory. When the user deletes the application, the cache folder will be deleted and also all the stored images.
Application build file(apk) size will be less as tofeeqahmad was suggesting.
I developed a mass file up loader (a swing application) recently.One of the new requirements is to support uploading thousands of documents (GIF,JPG,PNG,DOCX,XLSX), each of these are like 3MB-10MB of size and we don't want to upload these huge files, we generally support TIFF files which has small byte size like 60KB-100KB. We are not concerned about the image quality, all we need to upload these docs for future reference. Right now I don't have any idea how to solve this problem, I started researching it. Please point me in right direction.
-PD
My first approach would be to convert them to pdf files. Everything that can be printed can be converted to pdf. This also allows for image compression. Tiff won't be a good idea for doc/xls I think, it might make them bigger.
a .doc or .xlsx can be gzipped very quickly for decent savings.
Images are more risky, depends on what the data is. Pictures of people? Pictures of text?