mad-dev February 2001

mad-dev@lists.mars.org

17 participants
14 discussions

Compile libmad on other architecture
by Sunny Chan 28 Feb '01

28 Feb '01

Hello, I am trying to integrate libmad into my MP3 player project - I am trying to presuade make to compile using arm-elf-gcc & co instead of normal gcc - however if I do ./configure --target=arm-elf --enable-fpm=arm The autoconf script didn't change the compiler used by make therefore I can't compile it... How can I change the libmad so that it will use arm-elf-gcc, etc instead of normal gcc? Thanks!

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wrapping MAD (mad rocks)
by Rob Leslie 23 Feb '01

23 Feb '01

FYI -rob Read and respond to this message at: http://sourceforge.net/forum/message.php?msg_id=114204 By: coplan Just thought that everyone might like to know that our project, the SoundBox Project ( http://sourceforge.net/projects/soundbox ), has chosen MAD to be our key command-line MP3 player. For those of you who don't know, SoundBox is a project to turn your old computer parts into a digital audio jukebox for your stereo. It's actually a database front end, and music selection system that will make things easier. Besides, it gives us something to do with our old processors. =) We're only in planning stages now, but we don't mind help when it comes to certain parts of the project. One of the big things is that we're going to be wrapping madplay with a perl script -- and we're going to be throwing songs from the database at madplay on the fly. It'll be an interesting project. MAD rocks -- we're really impressed with the sound quality.

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MAD FreeBSD "Port"
by Jason R Mastaler 23 Feb '01

23 Feb '01

FreeBSD users; MAD is now part of the "Ports" collection which offers simplified software installation. See the `audio/mad' directory within your ports tree or <http://www.freebsd.org/ports/audio.html>. Enjoy.

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Mad with VC++ 6.0
by Guillaume.Delile＠infineon.com 20 Feb '01

20 Feb '01

Hi everybody, I'm a new user of this wonderful mp3 decoder. As anyone port mad under windows (VC++) ? I'm just looking for a simple decoder ( mp3 -> pcm) not a player. Thank you, and again good job ! Guillaume.

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mad performance question
by Gad Hayisraeli 19 Feb '01

19 Feb '01

i'm trying to get the best from madplay (0.2.12b), and my goal is to jump to certain milisecond in the song, when i get an interrupt (keyboard). i use mad_stream_skip within mad_header_dcode() to acheve this. while monitoring the latency between getting the interrupt and having the jump done, i noticed that both in assabet and intel PIII i acheve latency of between 2-50 miliseconds. by saying latency, i mean that while i wanted to jump to X position, i jumped de-facto to X+20ms, for example. can i make it better ? (i want to acheve <10ms or fixed latency up to 40ms) maybe my measure isnt right ? ( i take stream->current_frame time after the skip, when i get into mad_header_decode(), and the latency calculated by: latency=desired time-current time. maybe current time isnt calculated exctly ? mabe i need to use real-time linux kernel ? Gad

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Re: resample problem..
by Rob Leslie 15 Feb '01

15 Feb '01

J.Saravanan wrote: > Thanks for the reply.. > >>> output: sample frequency 44100 Hz not availlable;closest 41666 Hz >>> output: cannot resample 44100 Hz to 41666 Hz >>> >>> And the program quits. >>> Can sombody tell me how to fix this problem. >> >> Currently `madplay' only accepts hardware sampling frequencies within 3% of >> the requested frequency. >> >> You could increase this tolerance to 6% by modifying player.c around line >> 503. > > Is that the line start with 3L * ... > I've changed it with 6L * ... Yes. > The result is little different.. My board completely hangs. After some > time the linux kernel crashes with panic. > > Any other Idea.. Seems to me it is a problem with your sound driver in the kernel. -- Rob Leslie rob(a)mars.org

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MAD 0.12.5b available
by Rob Leslie 13 Feb '01

13 Feb '01

Hot on the heels of 0.12.4b, MAD 0.12.5b is now available with even more performance improvements. This version incorporates the long-awaited Huffman decoding optimization that performs requantization in the same step. Many thanks to Andre McCurdy for his help that led to this release. There are still a few more improvements to be made, but this probably represents the bulk of what can be optimized for significant gains. The source code release: ftp://ftp.mars.org/pub/mpeg/ The MAD plug-in for Winamp: http://www.mars.org/home/rob/proj/mpeg/mad-plugin/ The MAD home page: http://www.mars.org/home/rob/proj/mpeg/ Cheers, -- Rob Leslie rob(a)mars.org

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Re: [mad-user] resample problem..
by Rob Leslie 12 Feb '01

12 Feb '01

"J.Saravanan" wrote: > I've compiled madplay for my arm target ( Its a CLPS7500 evaluation > board). When I try to run the application I get the following error > message... > > output: sample frequency 44100 Hz not availlable;closest 41666 Hz > output: cannot resample 44100 Hz to 41666 Hz > > And the program quits. > Can sombody tell me how to fix this problem. Currently `madplay' only accepts hardware sampling frequencies within 3% of the requested frequency. You could increase this tolerance to 6% by modifying player.c around line 503. (Maybe this is a better tolerance? Follow-ups to mad-dev please...) -- Rob Leslie rob(a)mars.org

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MAD 0.12.4b available
by Rob Leslie 11 Feb '01

11 Feb '01

MAD 0.12.4b is now available. This version incorporates a number of performance improvements for all platforms. It also includes (untested) native fixed-point math support for the PowerPC platform, contributed by David Blythe. Since I've made some significant changes to the way the fixed-point math routines are maintained, I'd appreciate feedback from anyone using MAD on a PPC to make sure I haven't broken anything. Finally, this version changes the way mixed short blocks are handled in Layer III with respect to alias reduction, correcting another apparent ambiguity in ISO/IEC 11172-3. Since mixed blocks are rare (many encoders don't support them) this has until now gone unnoticed. Thanks to H.O. for reporting this. The source code release is here: ftp://ftp.mars.org/pub/mpeg/ Winamp users should notice improved performance in the MAD plug-in: http://www.mars.org/home/rob/proj/mpeg/mad-plugin/ The MAD home page is, of course: http://www.mars.org/home/rob/proj/mpeg/ Cheers, -- Rob Leslie rob(a)mars.org

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alias reduction for mixed short blocks
by Rob Leslie 09 Feb '01

09 Feb '01

A quick note on the alias reduction change for mixed short blocks: Haruhiko Ogasawara informed me that in spite of ISO/IEC 11172-3's claim that "alias reduction is not applied for granules with block_type == 2 (short block)", alias reduction most likely should be applied to the lower two subbands of mixed short blocks, as these are long blocks. Of the decoders that support mixed blocks at all, most indeed apply alias reduction on the lower subbands, including recent FhG implementations. Apparently version 3.0 of FhG's reference decoder l3dec does NOT apply alias reduction here, however, so there's a bit of ambiguity. Consequently, I've added a new option --enable-strict-iso to `configure' to revert to the previous behavior. This is not enabled by default. A few examples of files encoded with alias vs. no alias reduction are here: http://www.geocities.com/nazone2001/ You'll find that the mixed_alias file has aliasing artifacts when decoded with MAD 0.12.3b but not with MAD 0.12.4b, and for the mixed_no_alias file vice versa. Presumably the mixed_alias file is the one which is correctly encoded. I know there are some LAME developers on this list: will the mixed block support coming in LAME perform alias reduction on the lower two subbands of mixed short blocks? -rob

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mad-dev February 2001