mad-dev June 2003

mad-dev@lists.mars.org

8 participants
8 discussions

mad_frame subbands and filtering
by Bill Zissimopoulos 08 Jul '03

08 Jul '03

I need to process frame subbands before synthesis occurs. Libmad conveniently makes them available through its filtering feature. However the information around filtering is rather limited. I have studied the source code in filter.c and (think that I) have read all the relevant articles in this list, so I understand the basics, however I do have a few more questions: 1. What are the units and range of values for each subband? Must these values be scaled before they can be used? [I saw in a list article that subband values range from -MAD_F_ONE to MAD_F_ONE. Have these values been scaled?] 2. What are the frequency ranges that each subband covers? Many thanks. Bill

3 2

mad ogg support
by Joe Drew 03 Jul '03

03 Jul '03

Hi Rob, I remember you mentioning that you might implement a sort of mad-ogg which was a integer-only ogg vorbis decoder, but you were stymied by the lack of a proper specification for the ogg vorbis format. Now that Tremor has been released, do you still plan on making such a project? Thanks, Joe

4 3

help for missing files !! Urgent !!
by Bhumika 23 Jun '03

23 Jun '03

Hi, We are trying to build the VLC code in WinCE. We are not able to bulid as some of the files are missing in MAD library. Following files are missing, 1. libmad.c 2. layer1.c 3. layer2.c 4. errno.h 5. math.c These 5 files are being used in VLC source code. We checked the source code available in FTP as well as in Mirror site. But we didnt fine these files there also. If we get these files it will be helpful for us to compile and build the source code. Please help us as it very urgent for us. Thanks, Bhumika

3 3

24 bit PCM output
by alok 23 Jun '03

23 Jun '03

Hi All, I am new to MAD Mpeg Decoder. I just want to know from which part of source code i can come to know that output will be 24 bit PCM. Regards,

2 1

Porting to PocketPC
by Tyler Montbriand 19 Jun '03

19 Jun '03

I've been attempting to port MAD to Windows CE running under ARM... it's tricky going, so far. I'm trying to convert the tons of macros that the FPM_ARM option uses to function calls, and having some limited success. The biggest problem is that Embedded Visual C++, quite simply, does NOT support inline assembler. Ever. Despite what their own docs say. Another problem is that the macros aren't documented well; they don't explicitly state what kind of arguments they take or what they return. Fortunately, EvC DOES support *external* assembly code; you can assemble an .asm file into an .obj file, turn it into a .lib then link it in with the rest of the C code. Even more fortunately, EvC is capable of converting C code to assembly code. This lets me write up a blank framework, compile it, and modify the resulting .asm file to do what I want. So now I'm down to deciphering just exactly what each macro does to the arguments. It looks like mad_f_mul(x,y) takes two mad_fixed_t arguments and returns a mad_fixed_t value, that's simple enough; but it's unclear how the others are using their arguments. Are the macro parameters for MAD_F_MLX, MAD_F_MLA, MAD_F_MLN, and mad_f_scale64 used ONLY as input parameters? 'cause if not, there's no way in heck to duplicate the full functionality of the macro in a function without operator overloading and hidden pointers; and MAD is a C project, not a C++ one.

2 1

help for missing files !! Urgent !!
by Bhumika 18 Jun '03

18 Jun '03

1 0

x86 speedup diff for libmad 0.15.0b uploaded
by Felix von Leitner 06 Jun '03

06 Jun '03

I ported my x86 speedup diff to libmad 0.15.0b. It is a trivial diff that only touches the x86 assembly and replaces shrd with two faster instructions. shrd is slow as hell on today's x86 implementations because of the not normally used semantics regarding the CPU flags. On my Athlon, Pentium 3 and VIA C3 it is about 30% faster. http://www.fefe.de/diffs/libmad-0.15.0b-speedup.diff.gz Felix

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MAD suite 0.15.0b released
by Rob Leslie 05 Jun '03

05 Jun '03

At long last, MAD 0.15.0b is now available. This release is a bit different from previous releases: there are now independent packages for libmad, libid3tag, and madplay. There is not at this time an update to the MAD plug-in for Winamp; 0.14.2b is still the current release for the plug-in. Here is a summary of the important changes: General - Shared libraries are now built by default. - Cygwin builds have reverted to Cygwin dependency by default; MinGW builds are still possible with the --host=mingw32 option to 'configure'. libmad - Minor compatibility enhancements: 64th entry to Layer I/Layer II scalefactor table; allow reserved emphasis value in frame headers. - Bug fix for ARM mad_f_scale64() that was tickled by certain optimization options. - API additions: mad_f_div(), MAD_EMPHASIS_RESERVED. - Rewritten PPC fixed-point assembly. libid3tag - Numerous API additions: id3_tag_version(), id3_tag_options(), id3_tag_setlength(), id3_frame_field(), id3_field_getlatin1(), id3_field_getfulllatin1(), id3_genre_index(), id3_genre_number(), id3_latin1_ucs4duplicate(), id3_utf16_ucs4duplicate(), id3_utf8_ucs4duplicate(). - Fixed missing interfaces for other API routines. - Bug fix for segfault rendering ID3v1 tags. - Bug fix for reading ID3v2.2 frames. - Other miscellaneous improvements. madplay - Support for arbitrary resampling ratios (--sample-rate). - Support for RVA2 (relative volume adjustment) ID3 tag frames. - Keyboard controls for dynamic volume control (+/-). - Support for ancillary data output (--ancillary-output). - New audio_qnx, audio_alsa modules (untested). - New audio_carbon module (tested, for Mac OS X). - Other miscellaneous improvements. For complete details, see the CHANGES file in each package. Be sure also to review the README in each package for modified build/install instructions. You will find the new releases here: ftp://ftp.mars.org/pub/mpeg/ Windows developers who need zlib (no longer included with the above) can find a convenient package here: ftp://ftp.mars.org/pub/mpeg/extra/ (Note that zlib is already available as part of Cygwin, so you may only need this package if you are using MSVC++ or want to use MinGW to eliminate the Cygwin dependency.) Enjoy, -- Rob Leslie rob(a)mars.org

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mad-dev June 2003