mad-dev

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682 discussions

Decode time is longer than song time on ARM EP7312?
by Jimmy Lin 13 May '02

13 May '02

Hi all, I have compiled madplay-0.14.2 for ARM with the special following option: --host=arm-linux --enable-speed --disable-debugging --enable-fpm-arm Because, I don't have sound output device on my target right now , so I tried to run madplay with only DECODE on iPaq (StrongARM 210MHz) and EP7312 (ARM 74MHz) for compare. The test.mp3 is 128kbps, 44100Hz, joint stereo, 1m1.2s long. $ time ./madplay -v --output=wave:/dev/null test.mp3 iPaq: 11.857s EB7312: 1m5.539s What I got wrong? Does it mean my platform can't play mp3 smoothly? Any idea to improve the performance in that case? Thank you for your suggestion! Regards, Jimmy

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Cross compiling again
by Gareth Bransby 06 May '02

06 May '02

Hi, I maganged to get mad cross compiled with with an arm-linux cross compiler but it turs out that is not the wan I should be using. I have jsut built an arm-elf cross compiler and it works fin on simple programs. Now when i do ./configure I get the error : configure: error: can not run test program while cross compiling I understand why it can't run the test program but it never had a problem with the other cross-compiler. I tried giving it the --build=1686-linux along with the --host=arm-elf option so it would _know_ it was cross compiling but this made no difference. Is htere some other optin that i can pass to configure to stop it running test programs?

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Error 0x0101 ... using libmad...
by naso 03 May '02

03 May '02

Hi everybody, I'm Simone from Genoa. I'm using minimad for WinCE, so I had to modify it in some part. Now I believe I've done a good job, because the function "decode" does something... it calls "input" then calls "error". The message I get from "error" is the sequent: "decoding error 0x0101 at byte offset 0" Does someone know what does it means (I've understood only that the error happens at the beginning of the file ".mp3", but the code 0x0101 doesn't tell me nothing...)? Thank you all. ---- Simone

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Equaliser style effect.. i.e visualisation.
by Thomas Rathbone 02 May '02

02 May '02

In what stage of the decoding process can i find the information I would need to create an equaliser (a frequencies bar graph) visualisation? Do I just look at the subband levels or is that totally wrong? Has anybody done this? Much thanks. Tom.

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id3 genre list
by Neil Hodge 01 May '02

01 May '02

All: How can I go about simply scrolling through the list of genres? I can't quite seem to get what I want. Thanks. -- Neil Hodge nhodge(a)attbi.com

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Using minimad.c...
by naso 29 Apr '02

29 Apr '02

Hi everybody, I've some problem because minimad read on the standard input the mp3 file and send the decoded PCM samples to the standard output, but I'm using WinCE, so I have to use an input file and an output file different from the standards. For the input I've done so: int main() { struct stat stat; FILE *test; int file_des; test = _wfopen(TEXT("\\a.mp3"), TEXT("r")); file_des = _fileno(test); fstat(file_des, &stat); /* 1. map input stream into memory */ decode(test, stat.st_size); } and I hope it goes well, but I tried to modify the output function discovering that it apparently never executes!!! I would like to send the PCM samples to a wave file (I already know how to write the chunks...) and play this .wav, but I don't understand how to catch this damned samples, help me, please!!! --- Simone

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How to play mp3 using libmad?
by naso 28 Apr '02

28 Apr '02

Hi everybody, I'm Simone from Genoa (Italy). >From some time I'm using the library mad.h (I compiled the WinCe version); to understand how to use mad.h I downloaded the program "minimad.c" and got the decoding from mp3 to PCM samples. Now I would like to hear this samples using WinCE, but I don't know how... Can You help me? I thank you all for your attention. -- Simone Naso

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Re: mad-dev digest, Vol 1 #149 - 4 msgs
by armin.gerritsen＠philips.com 26 Apr '02

26 Apr '02

>Doesn't make the DShow filter involve linking libmad with core MS libraries? >Isn't this illegal under the terms of the GPL? Why should it? I never saw anything in the GPL licence what would disallow that. BTW using any non-GPL compiler will have non-GPL libs linked in it. This regardless whether it is DShow or anything else. GPL doesn't say anything about that. If it did, you couldn't use GPL with *any* non-GPL compiler. And we all know that is no issue. :-) Armin

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Vorbis article
by Rob Leslie 26 Apr '02

26 Apr '02

I promised I would send a link for my article on Vorbis once it was posted. The article made the front page of K5. Here it is: http://www.kuro5hin.org/story/2002/4/25/212840/001 Cheers, -rob

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DirectShow filter based on MAD
by armin.gerritsen＠philips.com 25 Apr '02

25 Apr '02

Hello All, I just wanted to let you know I'm working a DirectShow filter implementation for MAD. Basically this is just a wrapper around the MAD library to create a DirectShow Transform Filter. (For those who know the DirectShow names it is clear now. :-) ). The core is finished now and I added a sample property page which displays copyright (and it makes it easier for future updates, since they would only have to focus on the properties and not the framework.) More simple said: the first stable working version is finished and available. I'd like to 'donate' it as should to the GPL world. What would you think is the best way? I though about contacting Rob, but doesn't respond. Probably just because he is very busy. Best regards, Armin -- Philips Semiconductors B.V. Systems Laboratory Eindhoven (PS-SLE) Building BE235, Hurksestraat 19, P.O.Box 218, 5600MD Eindhoven, The Netherlands E-mail: Armin.Gerritsen(a)philips.com

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Re: [mad-dev] DirectShow filter based on MAD
by armin.gerritsen＠philips.com 25 Apr '02

25 Apr '02

>Also I think there is this big question wether a GPL DShow filter is >considered as a program or as a library. Program .... It is "reasonably considered independent and separate work" :-) There is no way a COM writer can know or predict how and when its component is going to be used. It is 100% dynamic during runtime. In the COM philosophy it should also be considered independent to be flexible and re-usable. That is the whole idea of COM. For those who are not convinced: look at CORBA. I've been working on CORBVA for a few years before I started working on COM. You have GPL and non-GPL implementations. They operate however together and servers created by GPL cannot see the difference between a client created with a GPL implementation and a client created with a non-GPL version. Since COM is nothing more than a localised version of DCOM and the latter is sometimes called the Microsoft version of CORBA, the resemblance should be clear. Still not convinced! :-) See the GPL OpenDivX filter. > In the second case that means >you should be able to use it from other projects than GPL (or GPL >compatible). For example Windows Media Player is not allowed. But AFAIK >you can't deny this access to different programs while the Filter is >installed on the computer... I think in the GPL world a definition should be made once and for all about things like COM, CORBA, etc. Or actually, one should clear out that these things do indeed qualify as a program an not as a library. Now this topic keeps poping up again and again for no reason. But to keep back to the subject. I think I'm just going to wait for Rob's reply. And in case he - to my surprise - isn't interested I'm going to put up a SourceForge page or so. Regards, Armin

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Re: [mad-user] rendering using libid3tag
by Rob Leslie 23 Apr '02

23 Apr '02

[This thread belongs on mad-dev; note Reply-To. Dominic, I'm not sure whether you're subscribed there...] On Wednesday, April 10, 2002, at 10:26 PM, Dominic Mazzoni wrote: > I'd like to also switch over to using libid3tag. We had > been using id3lib, but it's buggy and has trouble compiling > on a lot of systems. > > Our needs are minimal. We're not trying to be the ultimate > ID3 editor; we just want to be able to read and write > the most common tags for convenience. > > I didn't see any documentation on libid3tag...did I miss > something? The sample code only uses a small subset > of its features. I documented some of the interface here: http://www.mars.org/mailman/public/mad-dev/2002-January/000439.html Although this doesn't cover rendering tags, it may answer some questions about the data structures. > Anyway, I was able to figure out how to use libid3tag > to import tags from a file. But I'm stuck trying to > render them using id3_tag_render. > > 1. First of all, the only way I was able to figure out to > add new frames was to muck around in the data structures. > Is this correct? It might be nice if there were more > API functions to make it easier... > > For example, id3lib has a "simple API" which provides > functions that let you add and/or query the most common > tags (Title, Artist, etc.), without mucking in the > data structure at all. You shouldn't need to muck with the data structures. The general approach to adding a frame is: frame = id3_frame_new("XXXX"); id3_tag_attachframe(tag, frame); By indicating the frame ID ("XXXX" above), libid3tag knows automatically which fields to create in the frame. For text frames, there are two fields, a text encoding and a string list. If you're using Unicode, you should be sure to set the text encoding accordingly: id3_field_settextencoding(&frame->fields[0], ID3_FIELD_TEXTENCODING_UTF_16); To manipulate the string list field, you can either make an array of id3_ucs4_t pointers and call id3_field_setstrings(), or you can call id3_field_addstring() once for each string. In either case, the strings you pass are copied, so it is your responsibility to dispose of them. > 2. What's the proper way to convert an ASCII string to > an id3_ucs4_t string? (I used a for loop, casting > chars to longs...is that OK?) Instead of your own loop, you can call id3_latin1_decode(). > 3. When I try to enable the ID3_TAG_OPTION_ID3V1, > the rendering fails. Is it supported? Yes, it is supported. Probably it failed for you because mucking around in the data structures corrupted them... > 4. Finally, I do get some bytes back from id3_tag_render > without the ID3V1 option, but when I prepend them to > the beginning of my MP3 file, programs don't recognize > them. In fact even libid3tag doesn't even load any > tags from the resulting file. Is there something else > I need to do to the id3_tag_render output? Nope; again I think the problem stems from corrupt data structures. > I'm including some of my source code below. Thanks for > any help anyone can offer. Your ::ExportID3() looks good; try the following MakeID3Frame() instead: struct id3_frame *MakeID3Frame(const char *name, const char *data) { struct id3_frame *frame; id3_latin1_t *latin1; id3_ucs4_t *ucs4; frame = id3_frame_new(name); latin1 = data; ucs4 = malloc((id3_latin1_length(latin1) + 1) * sizeof(*ucs4)); if (ucs4) { id3_latin1_decode(latin1, ucs4); id3_field_setstrings(&frame->fields[1], 1, &ucs4); free(ucs4); } return frame; } -- Rob Leslie rob(a)mars.org

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libid3tag DLLs for Win32
by Robert Kaye 18 Apr '02

18 Apr '02

Hi! First off, a big thanks to Rob for the cool decoder and the new Id3 lib implementation. I am going to dump the original and crappy Id3lib implementation from all of my projects as soon as I can. Hence the reason for my e-mail -- is there an MSVC++ build project available for building an id3tag.dll? I've got a Borland C++ Builder project that I'm trying to convert away from the classic ID3lib, and C++ Builder does not like working with .lib files generated with MSVC++. I've even tried creating my own DLL, but they don't seem to work correctly - - none of the text fields ever load any strings. Where I would expect a string, I get an int32 field. :-( I suspect that I missed some compilation settings somewhere... This also holds true for the madlib -- it would be nice to have a DLL of that as well -- I'll probably dump the Xing decoder from FreeAmp and use the Madlib instead. BTW: Check out http://www.musicbrainz.org to see what I am working on... -- --ruaok Freezerburn! All else is only icing. -- Soul Coughing Robert Kaye -- rob(a)eorbit.net -- http://www.mayhem-chaos.net

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mp3 information library
by Neil Hodge 17 Apr '02

17 Apr '02

All: I was wondering if anyone on the list knows of a good mp3 information (bitrate, sampling rate, total frames, etc) library, written in C, or a nice clean program that is conducive to being hacked up. Thanks. -- Neil Hodge nhodge(a)attbi.com

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api
by Henning, Brian 16 Apr '02

16 Apr '02

Hello- I have compiled the mad library on my windows 2000 machine using mingw. I have the libraries and headers now. Can someone guide me to some documentation for the mad api? Is it online? I didn't find it on the website but, maybe I just missed it. I would like to write a simple program that reads in mp3 frames and prints to the screen some info in the headers. Is there any example programs in the documentation? I would like to see a simple example of some code to read a frame/header and print it to the screen. thanks for any help!!! brian

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frame decoding question
by Haig C Didizian 11 Apr '02

11 Apr '02

Hello - I hope this question doesn't fall outside this list's domain, but I figure there's probably a ton of mp3 know-how in this group... :) Anyway, I was looking at the mp3 headers from a file, and my calculation of the frame length appears to be wrong, but I can't figure out why. The first frame of the file looks like this: ff f3 68 64 which tells me that this is a 48kbps MPEG2 Layer-3 file at 16000Hz in joint-stereo, which is true based on what madplay says. I'd like to calculate the frame size based on this info, and using this equation for Layer-III files from http://www.dv.co.yu/mpgscript/mpeghdr.htm - FrameLengthInBytes = 144 * BitRate / SampleRate + Padding I calculate that the frame size is 432 bytes. When I scan through the file given this information, I find a total of 1924 frames. When madplay scans through the file, though, it finds twice as many, 3848 frames. So it seems that my frame length is 2x too big. Why does this equation hold for my 128kbps version of the same file, but not for this version (or am I missing something obvious)? On that note, does anyone have any suggestions for an mp3 frame-related resource? The one I mentioned above seems decent, but if there are any better ones, I'd love to know... Thanks for any help, Haig

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Static and dynamic linking
by Gareth 11 Apr '02

11 Apr '02

Hi, Once I had compiled minimad for ARM using the Lart cross compiler I used the 'file' command to see some stats on the resulting executable. It tells me that the file is an ELF arm executable, dynamicly linked (uses shared libraries) and a few other things. Now shared libraried are linked at runtime, right? So when I take the minimad executable and dowload it onto the arm evaluator board the shared libraries will be left behind and it will not work. Is this reasoning correct or am i missing something? If I am correct how do I go about telling the compiler to do static linking? Thanks Gareth

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Recalculate CRC checksum
by Dirk Nehring 31 Mar '02

31 Mar '02

Hi, I'm writing a program to correct bad MP3 files (by dropping bad frames, dropping IDv2 tags on demand, etc.) by using libmad. One point is that I want to add an CRC-16 checksum to the header. Can I use the libmad low level interface for this (i.e. set protection bit, and call mad_frame_decode(), get crc-checksum from header->crc_target)? Any ideas? Dirk

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configure scripts and cross-compiling
by Tripp Lilley 29 Mar '02

29 Mar '02

In many places, the configure scripts do tests like this: case "$host" in ... Should those be changed to: case "$target" in ... ? I find, in trying to cross-compile for arm-linux from i686-linux (for the Rio Receiver), that the configure doesn't "do the right thing", which is what leads to the fix-make script in Jeff Mock's patch here: http://www.mock.com/receiver/demo/ I'd rather get the configure scripts "corrected" (if I am, in fact, right about the host vs. target bit) in the sources :) While I'm at it :) what would it take to get Jeff's Rio Receiver audio device patches applied? Thanks!

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Re: [mad-dev] MAD Licence and Static link
by armin.gerritsen＠philips.com 28 Mar '02

28 Mar '02

>You forgot the most important one: to qualify for this exemption, you >must "distribute [the non-GPL linking parts] as separate works." OK, but that is also no problem for me. The non-GPL part will be distributed only through and by the company and the generic part that uses MAD will be on some public non-company related server available to the whole world. Thanks for claring this up. I think I'm going to wrap the MAD in a GPL DirectShow COM component which will use an as generic possible setup (which for those who know DirectShow know, means basicly using standard MEDIATYPE definitions). That way there is no doubt about it that it is indeed independant and seperate from any other program ever using it. (So something similar to what they did with LAME.) Regards, Armin

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MAD Licence and Static link
by armin.gerritsen＠philips.com 28 Mar '02

28 Mar '02

Hello, I want to use MAD in a commercial product (COM component) on Windows and Windows CE. I understood, that if I link MAD as a seperate library (DLL), I would not break GPL. However, now I was wondering if I would link MAD staticaly, but make sure all calls are in one seperate source-file and distribute with the product that seperate source-file together with all documentation related to that file, giving credit to MAD, etc., and keep the rest of the source closed, I would still not break GPL. I'm actually only using MAD in the body of a function as in the following pseudo code: STATUS DecodeBuffer( inbuffer, outbuffer ) ; { /* Using MAD to decode the buffer */ } Maybe I get my company to make the whole product GPL, but I'm afraid that they'll not agree. :-) Using a DLL is of course an option, but I'd prefer to distribute just one object. But I definitly don't want to break GPL or so. Regards, Armin PS When will MAD support MP3pro? The MP3pro files I decode now, are played at too 'high speed'. I seems to get the bitrate incorrect.

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Re: mad-dev digest, Vol 1 #136 - 2 msgs
by armin.gerritsen＠philips.com 27 Mar '02

27 Mar '02

>If you use MAD as a DLL (not sure about the COM object), you have to distribute >your product under the GPL, too. This is not the Library (or lesser) GPL! The >same is for static linking. > >The complete license can be found under >http://www.gnu.org/copyleft/gpl.html Aha, I see there: "... If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. " So I need to make my sure the non-MAD part is - identifiable as sections of that are not derived from MAD - reasonably considered as an independent and separate work in itselve Part 1 is no problem. Part two is a problem when I link statically, even if I give that one source-file free. This means I do have to use my seperate source-file that uses MAD, as a independant module (DLL or even its own COM object as they did with LAME), which I need to make completely GPL too. I can link MAD statically in that DLL of course. That takes care of the 'seperate' part. And if the setup of that MAD-module object (DLL or COM or whatever) is generic enough to be considerred 'independant' from my COM object (in the sence that it is not *just* created for my own COM object), I don't have to give the COM source-code free. This shouldn't be that hard since I'm planning on re-using this MAD-based module in several other completely different projects too. So no static linking. ;-( >I always thought MP3pro is backward compatible? It is, but MAD identifies the bitrate incorrect in some cases. So it is a MAD problem. It is a comon problem that other decoders sometimes also have. Regards, Armin

1 0

MACC instruction
by Gabriel Bouvigne 25 Mar '02

25 Mar '02

Could someone explain why the multiply and accumulate instruction seems so important in Mad? Regards, ---- Gabriel Bouvigne www.mp3-tech.org personal page: http://gabriel.mp3-tech.org

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Decoding partial files (1st 30s)
by iroro 22 Mar '02

22 Mar '02

Hi maddev-group & Rob, I'd like to know the easiest way to decode partial files, for example only the first 30 seconds. for constant bitrate layer 3 encodings, the first 30 seconds can be calculated by time = (size * 8) / (bitrate * 1000)? [from the dev-archive you posted in response to Joe Drew's post: Seeking, frames and time] but to get the bitrate, you have to read @ least one frame and from them can calculate the # of frames necessary for 30seconds ? to make things more tricky ... in reading the CBR layer 3 frames you have to read into the subsequent frames to really know if a current frame has ended or not. I know most of the incremental file descriptor reading action happens "decode_input_read()" ...so if i manage to calculate the # of Frames that correspond to 30 seconds of pcm, what structures do i need to set to stop decoding after the #of frames has been reached? MAD_FLOW_IGNORE? so the more general question is what is the best way for CBR and VBR layer 3 encodings to decode just the first 30 seconds to pcm? especially without having to scan through the whole file ... thanks a lot, iroro -- --o0o------------------------------------------------------o0o-- minimis optime peractis, maxima bene agentur --o0o------------------------------------------------------o0o--

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Re: [mad-dev] how build a standalone mad for arm?
by acen10 19 Mar '02

19 Mar '02

hi Gareth, now i can run minimad and it output file,but what is the output file's format? it may be inputed directly to DAC? the madplay can output raw format file and it can play when i simply add wave format header to it. but minimad'output dont the same as madplay's. On 2002-03-18 11:38:00 Gareth wrote: >> i dont know how to initiate arm and set the start address >> using arm-linux.whether in ctr0.s ? > >I think the function 'decode' will just take a pointer to where the mp3 is. >In minimad.c : decode(fdm, stat.st_size); > >where fdm is the pointer to the mp3 data > >> what do the stdin and stdout refer to ? keyboard and screen? >> in minimad.c : >> int main(int argc, char *argv[]) >> { >> struct stat stat; >> void *fdm; >> >> if (argc != 1) >> return 1; >> .. >> if you run minimad with any parameters it will return doing >> nothing. > >Yes it will normally print the data to the screen so you redirect it to a >file using "> audio.pcm." > >"if (argc != 1)" means return if the arguments are not 1. So if there are no >arguments it will do nothing. > >Have you managed to compile minimad.c for arm yet? Best regards. acen10 acen10(a)263.net

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