mad-dev

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682 discussions

Re: C++ wrapper
by Erik Jälevik 17 Jan '04

17 Jan '04

I just looked through the archives to find information on MAD and if there was any higher-level way of getting an MP3 decoded and came across the recent post about a C++ wrapper. I'd be very interested in such a thing as I'm not particularly keen on implementing all the different callback functions if I don't have to. All I need is some method for getting one decoded sample at a time for further processing within a beat-tracking application. Samuel, what functionality do you have at the moment? Would it be possible to just send the wrapper a filename and then proceed to call a read() method or such? Does it take care of downsampling to 16-bit, frequency conversion (if necessary), checking endian-ness etc? Erik

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Intensity Stereo and LSF_EXT
by Grigory A. 14 Jan '04

14 Jan '04

Hi! I am sorry for my question. But ... could someone give me link or just send to my e-mail (no big please - up to 1Mb) some audible mp3 bit-streams with Intensity Stereo and Intensity Stereo LSF_EXT stereo data encoding? Thanks. And sorry again. Best regards, Grigory mailto:Ryhor@tut.by

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C++ wrapper
by Samuel Krempp 10 Jan '04

10 Jan '04

Is there interest in a C++ wrapper to mad's API ? and for a simplistic one ? ;-) I'm asking, because I somehow ended up writing a simple C++ wrapper to MAD API. (a strictly C++ one. only ISO C++ headers used, plus shared_ptr from Boost.org, which is a high quality collection of standard-conforming, portable libraries) Atm it's providing access to the most important API features in some high-level way (plus lower level functions provided for finer control). for instance : std::ostream * destination; // a file, a custom stream, whatever.. using namespace MadSam; MadSam_Engine sam_engine; sam_engine.open_mp3("toto.mp3"); bool ok=true; while(ok) { ok = sam_engine.get_synth(); sam_engine.cur_synth_to_16bit_flow( *destination);//16-bit raw output } but it's far from polished (doesnt address all cases, the interface is not polished..). I'm using it in a toy decoder/player I'm writing (playing float samples with the jackit client API) ; and if this wrapper can be useful for MAD (eg as a sample for C++ developpers planning to use MAD, or whatever) I would try to make it as clean and self-explaining as I can. (but I would not spend weeks trying to make it feature-complete, though) BTW : the madlld example client would deserve a link somewhere on MAD's web pages. I think it's the best documentation material for newcomers at this moment, and I only found a reference to it after downloading the whole mail archive. (so I mostly used minimad.c to get into the API, and it wasnt as smooth as it would have been if I had known about madlld.c) -- Samuel

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mad in motorola dsp?
by Kampschreur_FP 11 Dec '03

11 Dec '03

Hello, I am de student from the Netherlands and I am working on a mpeg project. I have to decode mpeg realtime thus not out of a file into de decoder and into a file, but from an satilite into (buffer) the decoder into a DAC so there comes sound out of it. My question is Does enyone know if de libmab source fits into a Motorola DSP 56362 ? This is a 24 bit DSP so I have some problems whit fitting de intergers. thank you, -François-

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urgent: Questions about how to build a ARM based madplay
by Kzhang 11 Dec '03

11 Dec '03

Hi friends, I download both of mad-0.14.2b and madplay-0.15.0b, and I try to build a ARM based player, but I met problem to change gcc to arm-linux-gcc with ./configure command. I work on a ReHat 9.0 PC as host, and use arm cross compiler 2.95.3 toolchain. I try " CC=arm-linux-gcc ./configure" and "env CC=armlinux-gcc", it did not work. Please give me some tips how to build it, I very appreciate for your help. Thanks. Keji Zhang kzhang(a)neomagic.com

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MAD 0.15 Accuracy
by Grigory A. 04 Dec '03

04 Dec '03

Hi! I tested my implementation of some math function for MAD 0.15 library. And I have found this: function mad_fixed_t III_requantize(unsigned int value, signed int exp) in layer3.c file input value=8 exp=-23; that means 8^(4/3)*2(-5.75) correct? result obtained by mad_f_todouble(requantized)is 0.297241 but calculator says >> 8^(4/3)*2^(-5.75) ans = 0.29730177875068 for Q15 format its means ~2 bits difference. >>(0.29730177875068-0.29724100000000)*32768 ans = 1.99159810228230 my Q15 arithmetics gives: 9743/32768=0.29733276367188 >>(0.29730177875068-0.29733276367188)*32768 ans = -1.01531389788215 -1 bit difference And total difference between MAD math and my = 3 bits! Maybe I have to compare my math not with MAD - but with some float point implementation? -- Best regards, Grigory mailto:Ryhor@tut.by

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IMDCT accuracy
by Rafael Avila de Espíndola 03 Dec '03

03 Dec '03

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Testing the Rob Leslie implementation of the Szu-Wei Lee algorithm I notice that his modification (multiplying the input of the DCTIV by 2 and dividing the output) generally improves the accuracy but, in some cases, may cause a overflow. I have not found a .mp3 file that triggers a overflow, but the following data does. The present IMDCT implementation in libmad 0.15 return a valid result. 0x442D46F 0x217CC40 0x8E26853 0xF1888C6 0x921BF17 0xD282 0xF060CB8 0x3E82D68 0xBCA6124 0x1217700 0x9500F6D 0x3E9B4B6 0xC4B7675 0x6AE1645 0x56C266C 0x4463FD6 0x7EE5176 0xC408F90 Is there some evidence that no real mp3 may trigger an overflow? Thanks for any help. Rafael Espíndola -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/y2NVLlrfGJ8JUHwRAibvAJ9OtOIAoFi3UlKMqscFYUZIquCeGwCcCFLC 563s6VSqX5vnPxdTZNZAR/g= =yIV7 -----END PGP SIGNATURE-----

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MAD doesn't decode last frame in stream buffer unless it has 8 bytes extra
by Jedediah Smith 03 Dec '03

03 Dec '03

Pass a buffer to mad_stream_buffer which ends exactly on a frame boundary. mad_frame_decode will fail on the last frame and set the error to MAD_ERROR_BUFLEN even though entire frame is there. As much as 7 extra bytes can be added to the end of the buffer and the last frame decode will still fail. If 8 bytes are added, the frame decode will succeed. Is this a bug or by design? If by design, how can I decode the last frame without adding padding after it?

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Problem with this mp3
by starz 02 Dec '03

02 Dec '03

OK, I'm having problems using MPD (http://musicpd.org) or mpg321 with this file http://thelinuxshow.com/archives/2003/tls-11-25-2003.mp3 (actually any of the mp3s in that archive). Alsaplayer plays it fine, and some others have said it plays fine in MPD, which makes me think this is a libao problem, but I have tried this in XMMS with the xmms-mad module and it doesn't seem to work there either. Any ideas? Is this a known bug? Many thanks, sbh P.S. mpg123 and mpg321 report different values for the bitrate and samples... please don't ask me anything too technical as I'm the definition of 'enduser' :) _____________________________________________ Free email with personality! Over 200 domains! http://www.MyOwnEmail.com Looking for friendships,romance and more? http://www.MyOwnFriends.com

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random seeking with MAD
by Jedediah Smith 01 Dec '03

01 Dec '03

How would I implement fast, sample-resolution random seeking with MAD? In other words, I need to be able to reposition the stream to a specific sample and get resynced in constant time and without too much overhead. The MP3 also needs to be streamed from disk rather than loaded entirely in RAM. I imagine the main problem would be reconstructing the bit pool at the seek point. From my understanding of the MP3 format, the furthest back bit pool data can be stored is 9 frames. So here is my idea: 1. On initial load, create an index of all the frame offsets in the mp3 and cache it in RAM 2. When seeking to sample N, calculate the containing frame number F as F=N/1152 3. Use the cached frame index to find the file offset of frame F-9 4. Seek to that offset in the file and begin decoding 5. Decode 9 frames silently, ignoring any MAD_ERROR_BADDATAPTR 6. Begin playing at sample N which is within the current frame Will this work? Is there a faster way that avoids decoding the audio data for the extra 9 frames?

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How to unroll the imdct??
by forks.tw 30 Nov '03

30 Nov '03

The IMDCT function in MAD seems not easy to understand. Rob Leslie says that it is custom unrolled and factorized implementation. But I still don't know how ... Would you please tell me about the IMDCT algorithm in MAD or any reference documents? Thank you very much!! -- forks forks.tw(a)yahoo.com.tw --------------------------------- Do you Yahoo!? Free Pop-Up Blocker - Get it now

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error recovery?
by Gerd Knorr 28 Nov '03

28 Nov '03

Hi, Any hints how to recover from decoding errors, i.e. how to continue after mad_frame_decode() returned MAD_ERROR_LOSTSYNC? Just call mad_stream_buffer() with the next data block and then mad_frame_decode() again seems not to work. In the mad.h header file is a function called "mad_stream_sync", should I call that one? Before calling mad_stream_buffer() or thereafter? Gerd -- You have a new virus in /var/mail/kraxel

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RE: [mad-dev] A question for mmap()
by hank.jan＠billionton.com.tw 27 Nov '03

27 Nov '03

Hi, The explanation is very clear. Thanks a lot. Regards, Hank -----Original Message----- From: Jesse McGrew [mailto:jmcgrew@hansprestige.com] Sent: Thursday, November 27, 2003 3:12 PM To: mad-dev(a)lists.mars.org Subject: Re: [mad-dev] A question for mmap() On Thu, 27 Nov 2003 14:57:11 +0800, <hank.jan(a)billionton.com.tw> wrote: > I have a question about mmap(), hope someone can clarify for me. > As I know, mmap() maps the whole file into memory, so OS can access the > source file directly from memory. > However there should be a restriction to memory size on the embedded > system. > > In my test, I compile madplay with mmap supported, and then play a mp3 > file > of 43MB, and it plays well. > But my question is I only get 32MB SDRAM on my development board. > It seems that the memory size is not large enough to store all the data. > How does mmap() work? mmap() maps pages of memory to correspond to the file, but it doesn't actually load the file into memory. The file is loaded on demand. When you access one of the mapped pages, the OS loads the correct part of the file into memory. The effect is similar to virtual memory, where pages are swapped to and from the disk when they're needed. Thus, if you're using a 32 bit CPU, you may be able to map up to 4 GB with mmap(), even if you only have 32 MB of RAM. Adding more RAM will allow you to keep more of the file in memory at once, so random access will be faster, but it doesn't affect the size of the file you can map.

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A question for mmap()
by hank.jan＠billionton.com.tw 27 Nov '03

27 Nov '03

Hi, I have a question about mmap(), hope someone can clarify for me. As I know, mmap() maps the whole file into memory, so OS can access the source file directly from memory. However there should be a restriction to memory size on the embedded system. In my test, I compile madplay with mmap supported, and then play a mp3 file of 43MB, and it plays well. But my question is I only get 32MB SDRAM on my development board. It seems that the memory size is not large enough to store all the data. How does mmap() work? Besides, I want to implement the fast forward/rewind function. But it is a little slow to rewind, because it needs to search the location from the first frame, if mmap() isn't enabled. (Maybe there are other better methods, but I don't know...) If mmap() works, then it should be faster than without mmap(), shouldn't it? Sorry for any unclear expression. Thanks for help. Regards, Hank

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Re: [mad-user] Build problem with cygwin/mingw
by Jedediah Smith 17 Nov '03

17 Nov '03

This doesn't work.. error looks like this: /usr/bin/install -c .libs/libmad.lai c:\source\vc\mixer\libmad/lib/libmad.la /usr/bin/install: cannot create regular file `c:sourcevcmixerlibmad/lib/libmad.la': No such file or directory Those windows paths just aren't making it through everything without getting mangled. How exactly would I install manually? Just copy libmad.a? On Fri, 14 Nov 2003 14:22:02 -0800, Rob Leslie <rob(a)mars.org> wrote: > [Note Reply-To.] > > On Nov 14, 2003, at 12:52 PM, Jedediah Smith wrote: >> Following steps were followed: >> >> ./configure --host=mingw32 --prefix==/cygdrive/c/source/vc/mixer/libmad >> >> Configure step goes fine. The prefix is the dir I want to install to >> e.g. c:\source\vc\mixer\libmad which already exists. > [...] >> ranlib /cygdrive/c/source/vc/mixer/libmad/lib/libmad.a >> c:\mingw\bin\ranlib.exe: >> /cygdrive/c/source/vc/mixer/libmad/lib/libmad.a: No such file or >> directory > [...] >> It looks like ranlib is being passed the cygwin version of the path but >> it doesn't recognize it as it's part of mingw and only allows normal >> Windows paths. What shall I do about this? > > I think both Cygwin and Mingw understand Windows paths, so try: > > ./configure --host=mingw32 --prefix='C:\\source\\vc\\mixer\\libmad' > > If not you can just install the library by hand; libmad doesn't hardcode > any paths from the configured prefix, so it's safe to omit. >

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how must I align buffers passed to mad_stream_buffer?
by Jedediah Smith 17 Nov '03

17 Nov '03

My decoder uses an arbitrary buffer length and passes data blocks of this size, read from the MP3 file, to mad_stream_buffer. However, MAD throws a "lost synchronization" error immediately after returning from the input callback which feeds the data to mad_stream_buffer. The resulting decoded audio has artifacts at the equivelant locations. Clearly mad expects the MP3 data to be aligned, perhaps on frame boundaries, but I can't find any mention of this in the source comments.

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III_decode function question
by Grigory Abuladze 07 Nov '03

07 Nov '03

Hi! I am working with mad-0.15.0 Could someone explain to me this? why in III_decode() - layer3.c the IMDCT processing is split for subBand 0-1 & rest - up to 31? It is look like subBand 0 & 1 is not tested to "nonzero" Is it reason for this split? Thank for Your answers. -- Best regards, Grigory mailto:Ryhor@tut.by

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AM_MAINTAINER_MODE
by Dominic Mazzoni 27 Oct '03

27 Oct '03

For convenience, I have specific versions of libmad and libid3tag checked into the Audacity CVS tree, so that developers can get a known working version of all dependencies easily. However, we've been running into the well-known problem where CVS timestamps interact with "make" poorly; running "make" triggers all of the autotools even though configure.ac and Makefile.am haven't been touched, and this causes the build process to fail when users have incompatible versions of the autotools. It looks like AM_MAINTAINER_MODE may be a solution to this problem. It turns off the rules that call autotools by default, unless specifically enabled as an options to configure. I tried adding AM_MAINTAINER_MODE to configure.ac in libid3tag, but I can't seem to get it to generate a working configure script. After editing configure.ac, if I run aclocal and then autoconf, I get: configure.ac:66: error: possibly undefined macro: AC_PROG_LIBTOOL Running libtoolize doesn't help. If I run automake, I get: Makefile.am:27: Libtool library used but `LIBTOOL' is undefined Can anyone help straighten me out? Note that AM_MAINTAINER_MODE doesn't seem to be the problem; I'm not able to run automake even in a clean download of libid3tag-0.15.0b. Thanks, Dominic P.S. Versions I have installed: autoconf 2.57 automake 1.7.7 libtoolize 1.4.2

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III_requantize question
by Grigory Abuladze 20 Oct '03

20 Oct '03

Hi! I am working with mad-0.15.0 I hope someone may give me answer on this questions: 1. The result of this function III_exponents() in layer3.c file is signed int exponents[39] array. My question - in which format is result presented? 2. Xr = is^(4/3) * 2^(exp) (sign not discussed) What value exp can be and what step? -88.5 <= exp <= 11.5, 0 <= is[i] <= 8207 are this equation true? From III_requantize() it is look like step is 2^(1/4) - where can I take this information? Thank for Your answers. -- Best regards, Grigory mailto:Ryhor@tut.by

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[patch] libdid3tag - getting text encoding value
by Alastair Tse 20 Oct '03

20 Oct '03

Hi, I'm not sure where patches should be sent, so please re-direct me if this is not the best place. I've been writing a small program to help me convert ID3 tags from Big5 encoding to UTF-8 and libid3tag has made it _really_ easy. The API is so much cleaner than id3lib :) Anyway, I came across a bug which prevented me from fetching the text encoding value using id3_field_getint() from a field of type ID3_FIELD_TYPE_TEXTENCODING. Here is a simple one-liner to fix this behaviour. I hope it can be included in the next version. On another note, is there anyone who has python bindings for libid3tag? If not, I'd probably spend a little time writing some. Cheers, -- Alastair 'liquidx' Tse >> Gentoo Developer >> http://www.liquidx.net/ | http://dev.gentoo.org/~liquidx/ >> GPG Key : http://dev.gentoo.org/~liquidx/liquidx_gentoo_org.asc >> FingerPrint : 579A 9B0E 43E8 0E40 EE93 BB1C 38CE 1C7B 3907 14F6

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Can't output to alsa from madplay.
by Thomas Eriksson 18 Oct '03

18 Oct '03

I've been trying out the new madplay 0.15 with alsa compiled in, I cannot seem to get the output working though, The thing is, when I start madplay it doesn't output any error messages but it doesn't start to decode either, complete silence, when using the "madplay -v file.mp3" to go verbose, madplay just stays at starttime: MPEG Audio Decoder 0.15.0 (beta) - Copyright (C) 2000-2003 Robert Leslie et al. 00:00:00 Layer III, 160 kbps, 44100 Hz, joint stereo (LR), no CRC trying to open the alsa device with another program while madplay runs, in my case "ecasound", tells me that the alsa device is busy "madplay --version" shows madplay 0.15.0 (beta) Copyright (C) 2000-2003 Robert Leslie Build options: AUDIO_DEFAULT=audio_alsa ENABLE_NLS `madplay --license' for license and warranty information. I'm usually using madplay to pipe to ecasound to get 24bit percision support, this still works flawlessy. I'm no(t yet a) C programmer so I'm quite unable to resolve this problem myself, if I've omitted some vital information I'd be glad to supply this. /Thomas Eriksson

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.raw file size
by Rafael Avila de Espíndola 27 Sep '03

27 Sep '03

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I have noticed that that the .raw files generated by minimad and madplay differ slightly. For example, decoding a small .mp3 file the result was: 2428416 with madplay 2433024 with minimad What is the reason for this? Thanks. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/cPB/LlrfGJ8JUHwRAqm+AJ9FrsixBLd9wFzNy0xn0s0NaN6logCgnryW n/Y8zwqihqREzsDEPoereV4= =Jvdw -----END PGP SIGNATURE-----

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Need help
by veera malai 26 Sep '03

26 Sep '03

Hi, I have downloaded the free MP3 source code. But I am not able to open the files. The files are in .tar and .tar.gz format. Can anybody help me to open the files? Regards, Veeramalai.R ___________________________________________________ Meet your old school or college friends from 1 Million + database... Click here to reunite www.batchmates.com/rediff.asp

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libid3tag compatibility
by Dominic Mazzoni 25 Sep '03

25 Sep '03

Recently some users of Audacity have noted that when they save ID3v2 tags, most programs do not seem to recognize them. One user specifically tried WinAmp 3, CDEx 1.5, Windows Media Player 6.4, and WMP 7.01. None of them recognized any ID3v2 tags from an MP3 file output by Audacity (which uses libid3tag). ID3v1 tags work fine by all of those programs. I tried the same experiment. I tried saving some MP3 files using the last version of Audacity (which uses libid3tag 0.14.2b) and also a recompiled version using libid3tag 0.15.0b. First of all, ID3v1 tags always worked fine. When I opened the ID3v2-tagged files using Audacity, all of the tags loaded properly. So clearly the tags are being written, and libid3tag is able to open them. iTunes also opens them and parses all of the tags correctly on my Mac. However, I downloaded a few id3lib-based programs for Linux, and none of these were able to parse the ID3v2 files. Not a single tag. XMMS also failed, but I'm not sure it's supposed to have ID3v2 support. I don't use Windows anymore, so I can't repeat the experiment with Windows Media Player or Winamp. If anyone's interested in the Audacity part of the code, here's a pointer: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/audacity/audacity-src/src/Ta… So... 1. Anyone have similar experiences? What level of support does most other software have for ID3v2 tags? 2. Are there any free programs out there you know of that write ID3v2 tags using libid3tag? It would be nice to see if they have the same behavior. It's possible that the bug is in Audacity. 3. Any plans to support writing older, but more compatible, versions of ID3 tags for better compatibility with other programs? Thanks, Dominic

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madplay 0.15b without mmap
by Rafael Avila de Espíndola 24 Sep '03

24 Sep '03

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I tried to compile madplay 0.15b without mmap( ./configure --disable-mmap ). Unfortunately the following error occurred: if gcc -DHAVE_CONFIG_H -I. -I. -I. -Iintl -DLOCALEDIR=\"/usr/local/share/ locale\" -Wall -march=i486 -g -O2 -MT player.o -MD -MP -MF ".deps/ player.Tpo" \ -c -o player.o `test -f 'player.c' || echo './'`player.c; \ then mv -f ".deps/player.Tpo" ".deps/player.Po"; \ else rm -f ".deps/player.Tpo"; exit 1; \ fi player.c: In function `map_file': player.c:302: warning: implicit declaration of function `mmap' player.c:302: error: `PROT_READ' undeclared (first use in this function) player.c:302: error: (Each undeclared identifier is reported only once player.c:302: error: for each function it appears in.) player.c:302: error: `MAP_SHARED' undeclared (first use in this function) player.c:302: warning: assignment makes pointer from integer without a cast player.c:303: error: `MAP_FAILED' undeclared (first use in this function) player.c:307: warning: implicit declaration of function `madvise' player.c:307: error: `MADV_SEQUENTIAL' undeclared (first use in this function) player.c: In function `unmap_file': player.c:320: warning: implicit declaration of function `munmap' make[2]: ** [player.o] Erro 1 make[2]: Leaving directory `/home/rafael/unicamp/iniciacao/madplay-0.15.0b' make[1]: ** [all-recursive] Erro 1 make[1]: Leaving directory `/home/rafael/unicamp/iniciacao/madplay-0.15.0b' make: ** [all] Erro 2 The system is a Debian unstable. Does someone knows what is wrong? Thanks. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQE/cOtdLlrfGJ8JUHwRAl++AJ0W1yWdm13lZNeeWG4qPbxTm4rQowCg0J5Z AnNoXwxyBarhkay3uuJQ/FA= =BAah -----END PGP SIGNATURE-----

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