mad-dev

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682 discussions

madplay for ucb1200 device
by Sang Hoon Lee 18 Jul '02

18 Jul '02

Dear experts, I installed madplay on StrongArm board using ucb1200 device. I think that the pcm or wav output file is correct, but when I run the madplay for playing mp3 file, the result is somewhat weird. I mean, if I play 30 sec's mp3 file with madplay, the output sound's length is about 28 seconds. So, the voice's frequency in that mp3 file sounds somewhat higher than that of the original. Please give me the light what I'm doing wrong. The followings are my experimental circumstances. compiler : arm-linux-gcc (skiff tool chain) changes : 1) compile with -DFPM_ARM option instead of FPM_INTEL 2) change audio device name in audio_oss.c /dev/dsp(audio?) -> /dev/ucb1200 source file : 44100kHz, stereo,(also tried mono file), 128 kbps, mp3 (When I hear the output pcm sound with other tool, it sounds good. but just only when using madplay for play mode, it sounds some higher (in frequency) and its play time is shorter.) Thanks for reading, and any comment will be welcomed. Best Regards, bawui

2 1

MAIN_DATA buffer
by Kshitiz Malik 12 Jul '02

12 Jul '02

Hi! I have been struggling with MAD's code for quite some time now, and have managed to understand almost all of it - except I haven't been able to figure out the way it manages a buffer of main_data for mp3 files. (I am working solely on the MP3 part of the decoder) The problem is, the function mad_frame_decode(which decodes ONE entire frame, excluding the polyphase filterbank) works as follows: 1) Read the sideinfo(the header's already been decoded) [ I don't know why, but apparently Rob had named all main_data_end pointers as main_data_begin. Of course, main_data_end for one frame is the beginning of main data for the other frame.... but they're slightly misleading ] 2) Depending on the value of main_data_end of the current frame, it collects together the main_data which has been buffered till now in an array, stream->(*main_data). I couldn't figure out how Rob does this. He actually looks at the NEXT frame, reads its main_data_end pointer, calculates a variable named frame_space according to: frame_space = stream->next_frame - mad_bit_nextbyte(&stream->ptr); This is the no. of bytes of main_data(which may belong to ANY of the subsequent frames) present in the current frame. So far, so good. Next up is the statement: md_len = si.main_data_begin + frame_space - next_md_begin; This has me absolutely stumped. ____________________________________________________________________________ ||| header +sideinfo | main_data ||| head + si | main_data ||| ----------------------------------------------------------------------------- ^ ^ si.main_data_begin next_md_begin If frame_space was the length of main data in the second frame above, md_len would be "the no. of main_data bytes in the next frame". But frame_space is the length of the first frame (above), so I don't really know what md_len stands for. Can someone please help me out here??? From this point onward, I absolutely cannot understand the way Rob is bufferring up main_data. I see a couple of memcpy's(), and I can guess what's happenning, but I'm not really sure. Also Rob, how did you manage keeping a main_data buffer without using a circular queue?? 3) After all this is done , III_decode is called, which is passed a pointer named ptr, which happens to point to the beginning of main_data for the current frame. III_decode actually decodes the Huffman bits ....and does the actual decoding. Can somebody please help me out with how the main_data buffer is built up (I know the basics, i.e, main_data of the current frame may be present in any of the previous frames, mani_data_end is a negative offset from the end of the frame...etc...etc) Thanks a lot!! Kshitiz __________________________________________________ Do You Yahoo!? Sign up for SBC Yahoo! Dial - First Month Free http://sbc.yahoo.com

2 1

RVA2 Support
by Ross McKillop 03 Jul '02

03 Jul '02

What is the status of the talked about RVA2 support - I'd heard from others that madplay either DID support it or was going to - is this included yet? Ross

2 1

Re: [mad-dev] The BIG picture
by Umar Qureshey 03 Jul '02

03 Jul '02

Hi Rob, My board uses the Cirrus CS4340 DAC. I guess what I'd like to know is would I need to come up with a driver which will take the data from a system file (such as /dev/dsp) and feed it to the DAC or is there some sort of generic implementation out there which I can tweak? Is OSS such a generic implementation? Thanks, Umar On Monday, July 1, 2002, at 03:46 PM, Umar Qureshey wrote: > I am working on a custom EP7212-based board running on Linux 2.4.18. I > would like to know what the "big picture" is of running mp3s on my > ARM-based board. From what I have gathered, I'd need to output mad's raw > PCS streams to a device in the /dev directory which would be linked to > the DAC. Is this correct? How would I create this link? Getting application PCM samples to your DAC is the business of the operating system's audio driver; the details depend on which driver you plan to use. If you use OSS, the interface is usually through /dev/dsp or /dev/sound/dsp. Actually the name is unimportant; what matters are the device major/minor numbers. Under Linux, /dev/dsp should be a character device with major number 14 and minor number 3; it can be created with `mknod' if it doesn't already exist. The device numbers link the node to the audio driver in the kernel, which then passes your PCM samples to your sound hardware. > Also, is there any special hardware initialization that needs to be done > to preset the board for decoding? If someone can outline the general > sequence before I delve into the details, that'll be very useful. Thank > you! I'm not familiar with the EP7212 in particular, so I'm not sure I can answer this question. However, if the board is running Linux, I imagine most of the details are handled for you by the OS. -- Rob Leslie rob(a)mars.org

1 0

The BIG picture
by Umar Qureshey 02 Jul '02

02 Jul '02

Hi, I am working on a custom EP7212-based board running on Linux 2.4.18. I would like to know what the "big picture" is of running mp3s on my ARM-based board. From what I have gathered, I'd need to output mad's raw PCS streams to a device in the /dev directory which would be linked to the DAC. Is this correct? How would I create this link? Also, is there any special hardware initialization that needs to be done to preset the board for decoding? If someone can outline the general sequence before I delve into the details, that'll be very useful. Thank you! Regards, Umar

2 1

low-level vs high-level API
by Mike Shea 02 Jul '02

02 Jul '02

Hi, I've been using MAD's high-level API (the one where you give it some call-back functions to use for output and input and stuff) for the past while. However, this API is not great for doing certain types of tasks. I'm wondering if there is any documentation or FAQs or anything of that sort out there on how to use the low-level API? Thanks, Mike Shea.

2 1

mad server, madplay resume problem
by Eric Lyons 28 Jun '02

28 Jun '02

Hi, sorry for a long initial post. I'm trying to adapt madplay as a server, with simplified settings (always stereo, no resampling, etc). The simplest form of this server (though perhaps not the one to implement) *continuously* decodes a stream read from a named pipe. If the read of the pipe fails, it decodes silence. Another named pipe is used to check the size of the server's buffer and to cause it to be flushed (and maybe shutdown/stop the server). This could be done by having the input callback always return data (either from the pipe or silence), never returning MAD_FLOW_STOP. But I'm wondering about ASYNC mode, and whether using it would somehow be better/similar. Having trouble figuring out how async mode works and its application. Any comments on the best way to do this? Secondarily, my madplay (x86 Linux,mad-0.14.2b with and without MMAP support) seems to barf after resuming from pause/stop. Just get noise (interesting noise, but not musical noise) out the audio device. Anyone else seen this behavior? Eric. __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com

2 1

Updating with libid3tag...
by Pigeon 24 Jun '02

24 Jun '02

Dear all, Hi... I've been following the e-mail archives about using libid3tag, like the http://www.mars.org/mailman/public/mad-dev/2002-January/000439.html and all those related threads. I'm wondering how I should be using it to update/change the information for, say, an mp3 file. I've been trying to do it using those id3_field_set* functions and then eventaully id3_tag_attachframe and id3_file_update. I have a brief look in the libid3tag source code and I'm not sure what I should be doing. And also I'm wondering if libid3tag can actually update the the file for me? Or I have to actually write to the write myself? Thanks a lot. Pigeon.

3 2

Porting to TI DSP C54xx series
by robert hung 22 Jun '02

22 Jun '02

Hi there, Have MADPLAY been ported to any TI DSP c54xx series? Thanks robert

3 3

DOS port
by Roger 21 Jun '02

21 Jun '02

Hi all, I'm new to the sourceforge thing, seen it about, and found some interesting code, but never really gone too far with anything. I found the mad project, and I've got it working under DOS (using the DJGPP toolset). I need something which can gracefully handle a power down at any point. I've played with FreeBSD/Linux, and read only file systems. But the boot time is just way too long. Anyway I originally ported the mpg123 library to DOS (see http://www.fareham.org/mpg123/index.htm ) but it's handling of VBR and unusual formats is poor (to be polite). I've got the MAD library working, and I'm just tidying up the audio initialisation and closedown code. At startup and shutdown there are still a few pops and crackles, also I need to move some buffer management code into the interrupt routine. Just a shout out to make sure that I'm not duplicating work done (or in progress) by anyone else. Also how do I go about getting this back into the code base (like the msvc++ tree) ? Thanks, Roger.

2 1

Help for using the MAD library
by Frédéric Aguilar 09 Jun '02

09 Jun '02

Good morning, I am planning to develop a MP3 player under ARM PDA (Pocket PC 2002) usable by blind people with speech synthesizer support. I think that it would be very interesting for them. I always have written original code. Unfortunately, I have never used third party library or code. So, I am a little lost. I have no idea how to use it. I have tried to compile it and I have lot of compilation errors. Furthermore, I don't understand the API structure. Would there be anyone to help me? Thanks in advance. Frédéric Aguilar.

1 0

Adding full streaming support to MAD WinAmp plugin
by Brian G. 09 Jun '02

09 Jun '02

Is anyone working on adding full streaming support to the MAD WinAmp plugin? If not, I would be willing to implement it. __________________________________________________ Do You Yahoo!? Yahoo! Tax Center - online filing with TurboTax http://taxes.yahoo.com/

1 0

Compiling for ARM7DI (not TDMI)
by Gareth Bransby 06 Jun '02

06 Jun '02

I have compiled the library for an ARM7TDMI core and it works fine in the ARM simulator, when the simulator is set up to act like an ARM7TDMI (Not surprising...) Sadly the hardware we have is an ARM7DI, it does not have an extened multiply unit and therefore has a baby when we put the code into it. Tried to force the compiler to compile for an ARM7DI target, but at the end of comilation received a host of errors, all relating to the SMULL instruction, only supported by the TDMI range of cores. (USed the -mcpu=ARM7DI flag in the makefile to set the target platform) Is there a way to compile the library without incurring the SMULL instructions? I recall something to do with a generic C file that was slower than the optimised assemly, but was platform independant, I just can't remember enough details to dig it out and get it working. Does anyone know anything about this mysterious C file? Many thanks

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Code size on ARM
by Gareth 05 Jun '02

05 Jun '02

I have got mad running on an ARM development board with no operating system using an arm-elf compiler and newlib that i built from source. I have modified minimad.c slightly to suit the application. It no longer takes command line arguments. The mp3 is compiled into the binary in an array so decode() is just passed the start address of this array. The output is still sent to stdout for now. mman.h is no longer needed. My problem is the compiled binary is 381K. The mp3 array is only 21K so this is not what is making it big. Are there any options i can pass to configure to optimise the code for size? This is what i passs to configure : --enable-speed --disable-debugging --enable-fpm=arm --disable-nls --disable-mmap --host=arm-elf The onnoying thing is a week ago the binary was compiling to about 220K. Now when i come back to it a week later after changing nothing it suddenly increases by 160K. Lastly, I am still not certain what this 'stat' struct is for. If I am passing the array to decode() can i replace stat.st_size with the size of the array? This is my main finction : { struct stat stat; unsigned char *fdm = &music[0]; //printf("Started :\n"); decode(fdm, stat.st_size); return 0; } Thanks

3 4

RE: [mad-dev] Code size on ARM
by Gareth 04 Jun '02

04 Jun '02

No i am not using the -g flag. What does it do? What do you mean i must stop? The code just runs on the board. I use AXD to download it with a multi-ICE interface and then tell it to go! When it is ready it will go in the flash so ther will be no need for a PC to be connected to it. -----Original Message----- From: Reza Naima [mailto:reza@reza.net] Sent: 04 June 2002 11:29 To: Gareth Subject: Re: [mad-dev] Code size on ARM Gareth wrote: > Thanks for the advice. I stripped the file and it is now 170k! That's less > than half the size! What are these symbols that have been stripped out? They > take up a lot of space. They're used for debugging mainly. Are you using the -g flag with gcc? If so, then you probably want to stop. Btw, how are you running your code without an operating system? -Reza

1 0

Upsampling
by armin.gerritsen＠philips.com 30 May '02

30 May '02

Hello, Is is possible to do automatic upsampling of MP3's? I mean, if for instance a MPEG file is 32kHz, the output can be 44,1kHz anyway. Unless I missed it, I had the impression it was not possible and have to go looking for other sources. Regards, Armin

4 3

libid3tag: writing tags to files
by Sam Clegg 30 May '02

30 May '02

I am finishing of the id3 editor for xmms-mad and I am at the point where I would like to add/update tags in files. Does/will libid3tag support writing tags to a file? It looks like id3_file_update is supposed to do this but isn't implemented yet. Line 454 of file.c: /* ... */ Is this the plan (in which case I will wait (or send patches!)) or should I just write my own code that used the render functions and then somehow prepends a v2 tag and appends a v1 tag like the code in audacity? sam -- sam clegg :: samc(a)superduper.net :: http://superduper.net/ :: PGP :: D91EE369 $superduper: .signature,v 1.4 2002/04/27 11:54:02 samc Exp $

2 1

mad on arm processor -- strange problems.
by Reza Naima 30 May '02

30 May '02

I'm trying to write some mp3 playing software (www.reza.net/rio/rrr.html) for the rio receiver using the mad libraries. I've followed the example from minimad, and I've been able to make some progress, but there are some issues I'm having. First though, the system specs : Linux version 2.2.14-rmk4-mercury17-v1.01 (root(a)sticky.mock.com) (gcc version 2.95.2 19991024 (release)) #15 Sun Feb 25 19:24:49 PST 2001 Processor : ARM/VLSI arm720 rev 2 I've compiled the libs using these options : ./configure --enable-fpm=arm --host=armv4l Now, when I to decode it, the following things happen : - input callback called - error callback called (MAD_ERROR_LOSTSYNC at frame 0) * i ignore this and keep processing * This error also occurs with minimad playing - output callback is called multiple times * I get some audio out, music + loud clicks, till it runs out of data to decode - input callback is called - error callback called (MAD_ERROR_LOSTSYNC) - error callback called * the error code varies here, so far I've seen either MAD_ERROR_BADSAMPLERATE or MAD_ERROR_BADDATAPTR - i stop decoding at this point. now, as I'm also getting the MAD_ERROR_LOSTSYNC with minimad, I'm guessing (hoping) that I'm feeding some incorrect compile option to the madlibs. Any thoughts would be greatly appreciated. Reza

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Decode MP3 at tx39
by davidlee 27 May '02

27 May '02

Dear All: I just do some work to make my develope board with tx3911 play MP3 with 22.05K sample rate. But when I use --downsample option to play 44.1Khz MP3, I must use another option -m, else there is terriable distortion. I wonder if somebody can give me some advise to improve the efficiency of my player(madplay). 李大冀 Email: davidlee(a)gv.com.tw

2 2

frame decoding questions
by Russell O'Connor 26 May '02

26 May '02

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 [To: mad-dev(a)lists.mars.org] I'm trying to implement better seeking in my application. First, easy question: I believe after calling mad_decode_header, the amount of (decoded) data in the next frame is: 64*MAD_NSBSAMPLES(&(sync.frame.header))*MAD_NCHANNELS(&(sync.frame.header)) Next question: after calling mad_decode_header, am I allowed to call mad_decode_frame to actually decode the frame? The idea being to seek to where I want be by calling decode_header a bunch of time till I get to where I want to be. I think decode_frame returns -1 after I call decode_header. I'm not sure if this the the behaviour to expect, or if I'm doing something wrong. - -- Russell O'Connor roconnor(a)math.berkeley.edu <http://www.math.berkeley.edu/~roconnor/> ``Later generations will regard set theory as a disease from which one has recovered.'' -- Poincare -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (SunOS) Comment: For info see http://www.gnupg.org iD8DBQE87v6KuZUa0PWVyWQRAnYWAJ9KyLO66lp5wJjSb4pKj0SOWp7tzQCcDubu mQRz82MfkI6fWF85Y97dzCw= =COB6 -----END PGP SIGNATURE-----

2 7

resample library
by Sam Clegg 16 May '02

16 May '02

I have noticed that there are many projects that reproduce the same sample conversion routines for changing sample rate / frequency / endieness / channels. Of the top of my head: esd/arts/xmms/madplay/ libaudiofile. Perhaps there is already such a library, but if not I was hoping that this could warrant the creation of a second 'companion' library to mad (libresample or something). It could also contain down mixing routines for combining channels. just a thought sam -- sam clegg :: samc(a)superduper.net :: http://superduper.net/ :: PGP :: D91EE369 $superduper: .signature,v 1.4 2002/04/27 11:54:02 samc Exp $

3 5

Equaliser style effect.. i.e visualisation.
by Thomas Rathbone 16 May '02

16 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.

2 4

using libmad for Arm processor...
by Simone SN. Naso 15 May '02

15 May '02

Hi all, I'm trying to use libmad under WindowsCE in an ARM system (pocket PC). I've modified minimad.c so it open a file .mp3 and try to write the PCM samples in an output file. I've experienced an error when minimad read the header of the input file, but I've ingored it as Rob Leslie said in an older mail. Now the program don't give me any error, but it writes void PCM samples in the output file. Does someone know what does it mean? Note that the problem is not writing the samples to the output file: the function of libmad that decompress the .mp3 returns all 0 PCM samples!!! Another problem: I would like to write a .wav file, so I need to get various information about the file .mp3 that minimad is reading. For example, I need to know the sample frequency; in the comments of minimad.c there's written: "header->sfreq contains the sample frequency of the input file" So I've used this variable and I've discovered that header->sfreq conteined 0! Is this thing correlated with the former I've written of?

1 0

errors and MAD_RECOVERABLE()
by Thomas Rathbone 14 May '02

14 May '02

Using the high level API. In the error callback if MAD_RECOVERABLE(stream->error) returns true how do I deal with the error? Do I just report the error and return MAD_FLOW_CONTINUE? Will madlib recover the error itself or do I have to fix the error before resuming?

2 1

rio receiver replacement software
by Reza Naima 13 May '02

13 May '02

I'm currently working on an open-source re-write of the client software for the rio receiver (http://www.reza.net/rrr.html). The device is based on a linux ARM processor built by the empeg team. I've noticed the audio_empeg.c file which is probably the way I want to go, but I'm not sure what to use for documentation. I've looked at both minimad.c and madlld.c files, but I still don't have a good feel for the best way to go about implementing the code. I basically have two buffers, one with raw MP3 data, and one where I need to write the post-processed data in empeg-friendly format. Any suggestions for a good reference? Should I go the low-level or high-level route? Thanks, Reza

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