How to convert a raw binary file into an image in C#

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Hello!

I need to find a way in C# to parse a binary file which contains an image in raw data (no headers, metadata, compresssion, etc.) in a 2-2-2-2 format. This is 2 bits for each RGB color and 2 bits for opacity. I need to read it and display the resulting image. I am new to C# and have not been able to find a relevant answer in the posts, any ideas? I am using VS 2008 Prof edition.

AQ

Posted 31-May-11 7:33am

ArmandoQ

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Sergey Alexandrovich Kryukov 31-May-11 13:37pm

Tag it! WPF or System.Drawing? There is no just "binary file". What format?
Basically imaging name space in the library you want to use; and you will get an answer. How come it's a problem?
--SA

ArmandoQ 31-May-11 14:06pm

It is System.Drawing. This is a custom format and it contains 2 bits for each color (RGB) and 2 bits for opacity. I need to read each byte and convert it to a pixel that I can then draw on the screen. I know the image is 800 x 600 and I know the values for each color and Alpha channel.

Sergey Alexandrovich Kryukov 31-May-11 13:38pm

If this is custom format -- tag your library you want to use. It's also easy to answer.
--SA

aidin Tajadod 31-May-11 13:59pm

Do you mean byte or bit?!

ArmandoQ 31-May-11 14:08pm

I have a BYTE that contains 2 BITS for each RGB color and 2 BITS for opacity. This is similar to 8 bpp format but we are using 2-2-2-2 coding.

2 solutions

Solution 1

If you are using System.Drawing then you may create a bitmap of the same size then use the SetPixel method (or, if performance matters, the LockBits one, see Bitmap.Lockbits[^] at MSDN). The straighforward transformation of the RGBA components is the simple multiplication ~~by 64~~ 85 (sorry 64 was plainly wrong :-O, see SAKryukov reply), but you may choose alternatives.

Posted 31-May-11 8:18am

CPallini

Updated 31-May-11 21:12pm

v2

Comments

ArmandoQ 31-May-11 14:24pm

It looks like this is just what I needed. I will code something and post results if it works.

Sergey Alexandrovich Kryukov 31-May-11 19:33pm

Basically, correct, but do not advise SetPixel (I'm afraid to imagine the performance in this case, hardly acceptable). Multiply by 64 is incorrect (surprise? count it! don't forget, 2 is not maximum but number of bits; yesotaso won't let me lie here, please see his comment :-). I voted 4 this time.

Please see my answer.
--SA

yesotaso 31-May-11 21:42pm

With all the good and bad we are mere mortals sir :)

Sergey Alexandrovich Kryukov 31-May-11 21:46pm

And some of us probably even head to hell... :-)
"Memento mori!" (But why you remember it right now? Everything goes all right so far... :-)
Thank you.
--SA

CPallini 1-Jun-11 3:13am

Yes, 85 is the correct factor, thank you for pointing out.

Sergey Alexandrovich Kryukov 1-Jun-11 3:21am

You're very welcome.
(I did not receive e-mail notification on this comment though as I would it you replied under the sub-tree of any my post.)
--SA

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-05-31T13:31:00

Solution 2

First rule. Do not use GetPixel/SetPixel: it's too slow! You can get acceptable performance only when you do it all at once.

Do the following. Create empty bitmap of the class System.Drawing.Bitmap and use System.Drawing.Bitmap.LockBits method. For pixelFormat, use System.Drawing.Imaging.PixelFormat.Format32bppPArgb (precisely this one, this is what you minimally need). Fill in the value of each pixel from your 2-2-2-2 data. Convert your 2-bit components for each color and opacity to 8-bit, so you maximum value of 3 is mapped to 255: byte component8 = component2 * 85 (sic!).

The code sample on this page will give you the idea how to address pixels and move data: http://msdn.microsoft.com/en-us/library/5ey6h79d(v=VS.100).aspx[^]. Pay attention for the use of System.Runtime.InteropServices.Marshal.

That should be enough to solve your problem.

—SA

Posted 31-May-11 13:31pm

Sergey Alexandrovich Kryukov

Comments

Manfred Rudolf Bihy 31-May-11 20:14pm

Sorry SA! Me thinks you got something mixed up.

1 * 64 = 64
2 * 64 = 128
3 * 64 = 192
4 * 64 = 256

Please explain to a mere mortal why you chose 85. Maybe I'm missing out on something here.
Enlighten me! :)

yesotaso 31-May-11 20:52pm

0 -> 0
1 -> 85
2 -> 170
3 -> 255 ?

Manfred Rudolf Bihy 31-May-11 21:08pm

:doh:
Caught, convicted, hanged!
I do feel a little dumb just right now.

Sergey Alexandrovich Kryukov 31-May-11 21:27pm

One lapsus by me, one by you... We mere mortals quit today :-) no big deal at all.
--SA

Manfred Rudolf Bihy 31-May-11 21:45pm

True! :)

Sergey Alexandrovich Kryukov 31-May-11 21:48pm

:-)

Sergey Alexandrovich Kryukov 31-May-11 21:44pm

Exactly. Thank you very much!
--SA

CPallini 1-Jun-11 3:16am

My 5.

Sergey Alexandrovich Kryukov 1-Jun-11 3:19am

Thank you very much.
--SA

ArmandoQ 7-Jun-11 16:11pm

Hello SA. Thanks for the answer, I have played with it and it is just what I needed. However, I still have one question: how do I get my original image.raw file in an array so I can do the bit manipulation. Sorry, but I am an embedded system engineer with extremely little knowledge of C# and object oriented in general.

georgootyVarghese 22-Jul-15 1:51am

Can anybody help me to convert the image raw data into imagebitmap in windows store app. please note that image raw data doesn't contains the header of the image.

Sergey Alexandrovich Kryukov 22-Jul-15 3:23am

You do it by reading my answer above. If you think something is missing, feel free to ask.
—SA