I am looking to analyze a given piece of music using C, reading from mp3 files, and outputs the tempo, pitch, key etc.
Is there an open source project already written for this or a way to just program it myself? I tried PortAudio, but it did not look correct for the test.
Mabe aubio (written in C) or Essentia (written in C++) fit your needs?
Related
I am working on a project to generate G-Code for 3D Model in STL Format.
Suggest me how I can do it
Basically this generated G-Code will be used with Milling CNC.
You need CAM Software, a program that has an algorithm that extracts the path of the STL drawing and based in the type of your machine, generate the correct CNC commands.
There are several proprietary programs for this on the market and it really depends on your machine type and tools. Maybe this link will help you get some ideas.
If you want to develop your own CAM, I warn you that this is not a trivial job...
I want to start on a hobby project that focuses on displaying audio files in a folder in a certain fashion and has the ability to play such an audio file and shows basic control options for playing. However, i'm struggling to find a fit programming language for this.
The displaying part shouldn't be too hard and can probably be done in most of the programming languages. The audio part is what concerns me the most since it's not the main focus of the project and should only do limited things (so it shouldn't be too hard) and i do not know anything about sound support in the programming languages i currently know. (Java, C and C++)
Specifically i would like to be able to do these things:
Play a sound file
Stop/pause a playing song
Adjust volume
Show a bar that displays the current position in the song
Most files will be .mp3 files but being able to process other formats is certainly a plus. Since this is just a small project it's ok if it runs just on Windows. Scalabilty would be nice but not required.
It would be nice to have a small overview of audio support/audio libraries of programming languages (i'm always up for something new) that can accomplish these simple things, in a not too complicated way, aswell as personal experiences.
In this way i hope to create a better understanding of which programming language fits my project best. (i would very much like to not have to change language mid-way the project)
--
Edit:
This is only for a later stage of the project if the first part was successfull: i will want to change the file names of the audio files that are displayed. (to make them follow a specific format)
I haven't written audio processing programs much, but I know a lot of them exist for C and C++. For Java perhaps, too, but I don't know Java. I had used audio with SDL in a game, but that doesn't have that many features and I don't recommend it.
There's this question asking for a library in C, and there are a couple of similar questions that SO brings up on the side. You may want to take a look at those.
You would also need to look for a library that loads different file types. SDL at least, only opens .wav files, which I believe most of the playback libraries would support. For MP3, you will most likely need an additional library. I know Audacity uses LAME Mp3 so I'm guessing that should be good.
Some of the functionalities you want is also doable by yourself. For example, knowing the length of the music and the amount you have already read, you will know how far in the audio you are. Adjusting the volume is also a multiplication (in the simplest case) that you can do on the audio data if the library doesn't provide it.
A very good choice seems to be PortAudio which is used by Audacity, and also recommended in the accepted answer of the question I mentioned above.
I've done audio apps in both Java and C++. Java development goes way faster because it's a more powerful language and has garbage collection, but JavaSound is a pretty awful solution for audio. Of course, there are wrappers for FFMPEG and other stuff, so you can get a lot of things working. Here's an example of a Java audio app: http://www.indabamusic.com/help/mantis
OTOH, C++ gives you lots of control, low latency and wealth of libraries. (another answer mentioned Portaudio, which is, indeed, great.) But you will definitely find it also has a much longer development cycle.
You can certainly do everything you want to do with either language.
I'd like to play a sound and have some way of reliably telling how much of it has thus far been played.
I've looked at several sound libraries but they are all horribly underdocumented and only seem to export a "PlaySound, no questions asked" routine.
I.e, I want this:
a = Sound(filename)
PlaySound(a);
while true:
print a.miliseconds_elapsed, a.length
sleep(1)
C, C++ or Python solutions preferred.
Thank you.
I use BASS Audio Library (http://www.un4seen.com/)
BASS is an audio library for use in Windows and Mac OSX software. Its purpose is to provide developers with powerful and efficient sample, stream (MP3, MP2, MP1, OGG, WAV, AIFF, custom generated, and more via add-ons), MOD music (XM, IT, S3M, MOD, MTM, UMX), MO3 music (MP3/OGG compressed MODs), and recording functions. All in a tiny DLL, under 100KB in size.*
A C program using BASS is as simple as
HSTREAM str;
BASS_Init(-1,44100,0,0,NULL);
BASS_Start();
str=BASS_StreamCreateFile(FALSE,filename,0,0,0);
BASS_ChannelPlay(str,FALSE);
while (BASS_ChannelIsActive(str)==BASS_ACTIVE_PLAYING) {
pos=BASS_ChannelGetPosition(str,BASS_POS_BYTE);
}
BASS_Stop();
BASS_Free();
This is most likely going to be both hardware-dependent (sound card etc) and OS-dependent (size of buffers used by OS etc).
Maybe it would help if you said a little more about what you're really trying to achieve and also whether we can make any assumptions about what hardware and OS this will run on ?
One possible solution: assume that the sound starts playing more or less immediately and then use a reasonably accurate timer to determine how much of the sound has played (since it will have a known, fixed sample rate).
I'm also looking for a nice Audiolibrary, where i can directly write on the Soundcards Buffer. I didn't have time yet to have a look at it myself, but pyAudio looks pretty nice. If you scroll down on the page you see an example similar like yours.
With help of the buffersize, number of channels and sample rate you can easily calculate the time each loop-step lasts and print it out.
I've searched the net but didn't found anything interesting. Maybe I'm doing something wrong.
I'm looking for sound synthesis API written on C, C++ or even Objective-C, which can synthesize different types of waves, effects are optional.
Here's a complete library/toolkit for FM (Frequency Modulation) synthesis:
link1
link2
If you have time to spare... creating simple sound synthesis from scratch is actually a fun endeavor. If you create a small buffer of 256 16 bit samples which represent either a sine. a sawtooth, block or pulse, you can copy these to a live audiobuffer (e.g. a small buffer (say 16kb)) which constantly loops. By staying ahead of the playposition, and constantly filling up the buffer with new values, you can create the soundoutput.
You can use the small buffers to combine these in interesting ways (simplest is just to add them together (additive synthesis)).
The frequency of the tone can be manipulated by using a bigger or smaller sampling step through the small buffers. Amplitude can be manipulated by scaling the samples before putting them into the output buffer.
Great fun experimenting with this!
If you have this step nailed, you can add more sophisticated effects like filters (low pass, high pass, etc) and effects (reverbs, echoes, etc)
R
Have you looked at the synthesis toolkit (STK)? It's in C++ (I don't think ObjC is the right language for audio synthesis, in fact audio units, Apple's own way of doing audio stuff, including generators/filters/effects... is in C++).
STK will run on Mac OS X, and iOS no problem (CoreAudio is supported), but will also run on Linux and Windows (Direct sound and ASIO), using RtAudio. It's really nicely done and lightweight, these guys have spent a lot of time thinking about it and it will definitely give you a big head start. It can handle loads of different audio file formats + midi (and hopefully OSC soon...).
There is also Create and CLAM which is huge, these include GUI components and many other things which you might or might not want. If you're only interested in doing sound synthesis I really recommend STK.
PortAudio is also a great C API that we used last semester in an audio programming course. It provides an audio callback...what more could you need!?
I haven't tried incorporating it with anything in Objective-C yet, but will report back when I do.
Writing audio synthesis algorithms in C/obj-C is quite difficult in my opinion. I would recommend writing your signal processing algorithms using PureData and then use ZenGarden or libpd to embed and interpret the pd patches in your app.
Another C++ library is nsound:
http://nsound.sourceforge.net
One can generate any kind of modulated signal using the Generator class or using the provided Sine class. Each time-step can have it's own instantaneous frequency and phase offset.
You can also experiment with the Python module to prototype your algorithm quickly, then implement in C++. It can produce pretty matplotlib plots from Python and even from C++!
Have you looked at CSound? It's an incredibly flexible audio generation platform, and can handle everything from simple waveform generation to FM synthesis and all kinds of filters. It also provides MIDI support, and you can extend it by writing custom opcodes. There's a full C API and several C++ APIs as well.
Is there a freely available library to create a MPEG (or any other simple video format) out of an image sequence ?
It must run on Linux too, and ideally have Python bindings.
I know there's mencoder (part of the mplayer project), and ffmpeg, which both can do this.
ffmpeg is a great (open source) program for building all kinds of video, and converting one type of video (a sequence of images in this case) into other types of video.
Usually it is utilized from the command line, but that is really just a wrapper around its internal libraries. It is expressly available to be used from within another program.
There are also python bindings that wrap the c api, though this particular project doesn't seem to be getting the best support (there are probably other projects out there doing the same thing).
There's also this link where someone has used ffmpeg to do something similar to what you're looking for.
GStreamer is a popular choice. It's a full multimedia framework much like DirectShow or QuickTime, has the advantage of having legally licensed codecs available, and has excellent Python bindings.
in c++ OpenCV (open source Computer Vision library from Intel) let you create an AVI file and just push frames inside...
but it's like shooting with a cannon to a fly.
Not a library, but mplayer has the ability to encode JPEG sequences to any kind of format. It runs on Linux, Windows, BSD and other platforms and you can write a python script if you want to use it with python.
ffmpeg has an API and also python bindings, seems to be the way to go !
Thanks
ffmpeg minimal runnable C example
I have provided a full runnable example at: How to resize a picture using ffmpeg's sws_scale()?