mad-dev April 2002

mad-dev@lists.mars.org

20 participants
13 discussions

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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mad-dev April 2002