Comments on: Lightweight SWF Header Reader (Java) II

By: ToescaC

ToescaC — Mon, 17 Dec 2012 13:54:05 +0000

Thanks for this component, very usefull.
I’ve noticed un bug with somes swf, where the “SWFDecompressor.java.uncompress” function enter in a infinite loop.

To correct this problem, I’ve replaced the code:

while ( !decompressor.finished())
{
try
{
int count = decompressor.inflate( buffer );//decompress the data into the buffer
stream.write(buffer, 0, count );
}
catch( DataFormatException dfe )
{
dfe.printStackTrace();
}
}

By this one:

int count = 1;
while ( !decompressor.finished()&& (count>0) )
{
try
{
count = decompressor.inflate( buffer );//decompress the data into the buffer
stream.write(buffer, 0, count );
}
catch( DataFormatException dfe )
{
dfe.printStackTrace();
}
}

By: cvg

cvg — Wed, 30 Nov 2011 19:42:33 +0000

very neat :)
thanks

By: Anon

Anon — Tue, 01 Mar 2011 19:43:30 +0000

thx!

By: Ferrero DBGM

Ferrero DBGM — Tue, 02 Feb 2010 20:13:49 +0000

Thank you!! :)

By: Pall Zoltan

Pall Zoltan — Fri, 11 Dec 2009 16:13:09 +0000

sweet sweet code, thank you! i’m porting SWFHeader to AS3, it can be very useful at runtime :)

cheers,
Z.

By: BateRiste

BateRiste — Tue, 28 Apr 2009 17:06:59 +0000

It seems that the jar file won’t work on Java 1.4?

By: Sebastian

Sebastian — Tue, 21 Oct 2008 10:03:41 +0000

Hi there,

this is already a litte old here, but I try…. you mentioned above that you are intrested in reading/writing meta data into the flash,… well I wonder if you ever managed to actually to do that ?!

By: Daniel

Daniel — Tue, 11 Sep 2007 04:08:54 +0000

The SWFHeader.java is not matching the classes in swfheader.jar. In SWFHeader.java it extends SWFCompression, but in the jar there is no SWFCompression, and SWFHeader doesn’t extends SWFCompression. Is the jar the latest one? It would be nice if you could post the current code.
The jar version is also printing some debug info to the output.
Also in both version an IOException it prints to standard error instead of throwing an exception, and at least the source code does the same when it finds an invalid file, and having the code I can just add this improvements.

By: Alexander

Alexander — Fri, 27 Jul 2007 17:15:28 +0000

Hello Andrus!
I tested your useful code with 2 swf files of v.5 and v.7.
It works correct for v.5

But for v.7 of SWF, getWidth and getHeight return wrong values
Those values are double converted from twips.
In the same time maxX and maxY contain correct size in pixels(!)

By: Brooks

Brooks — Sat, 24 Mar 2007 14:32:23 +0000

Yep, I noticed that bug regarding frame count awhile ago and fixed, but I apparently forgot to upload the files. I’ve now checked to make sure that the header reader accurately reads the number of frames up to the swf file format imposed limit of 16000. The files on the website have been updated accordingly.

By: sale gosse

sale gosse — Sat, 24 Mar 2007 14:25:54 +0000

It seems to be ok by remplacing

frameCount = ( frameCount 127 for the second swf[bytePointer] lead to the problem.

By: sale gosse

sale gosse — Sat, 24 Mar 2007 13:49:12 +0000

Ooops, the problem is
swf.getFrameCount() is

By: sale gosse

sale gosse — Sat, 24 Mar 2007 13:46:45 +0000

doesnt work with that one
[link removed]
(I know, this is disgusting but i’m serious)

By: OrtOfOn

OrtOfOn — Wed, 18 Oct 2006 09:33:04 +0000

Very Cool, thx Brooks !!!

OrtOfOn

By: Brooks

Brooks — Tue, 17 Oct 2006 14:25:04 +0000

Yep, I’m aware of that bug and have fixed. I updated the source files on the Web page, but I must not of updated the jar. The issue was the result of using an arbitrary byte position when reading in the packed bit “rectangle” construct the swf format uses.

I’ll compile a new jar, test and post an update.

Brooks

By: OrtOfOn

OrtOfOn — Tue, 17 Oct 2006 13:42:55 +0000

Sorry…. little mistake in my first comment…

The bug appears when youâ€™re trying to get info from an SWF bigger than 819 in width or height.

819 is the limit size of the stage to make the swfheader working.

Thx.

By: OrtOfOn

OrtOfOn — Tue, 17 Oct 2006 13:35:44 +0000

Hello andrus,

I was very happy when you made a JAR version of this tool but I found a bug and I’m not so good with bitwise operators then it’s difficult for me to fix it.

The bug appears when you’re trying to get info from an SWF bigger than 810 in width or height.

Do you know why ?

Thx in advance.

OrtOfOn

By: Anson Chiew

Anson Chiew — Fri, 13 Oct 2006 09:36:58 +0000

As the implementation of unsigned right shift in Java is not as expected, your parseHeader() does not work for all flash files. To fix the problem, simply change the following line

nbits = ( rect[0] >>> 3 );

nbits = (rect[0] & 0xff) >> 3;

For more details:
http://www.cs.utsa.edu/~wagner/laws/Abytes.html