I want to make a program that takes an MP3 file and breaks it into many smaller mp3 files based on 1-2 seconds of no sound (silence).
What is the easiest way to do this in c#?
Bass library. Bass has everything you need. It can access, record and edit media streams like mp3s, allowing you to sample the volume at different time points. It has a .net api, so you can use it in c#. Unfortunately it does cost money if you are using it for a commercial application, but they do provide a free non-commercial license.
Sox is a command-line tool which has an option to split an mp3 on n seconds of silence. You could always use the system command to call sox from c#.
Other related links.
Ripping a CD to mp3 in C# - third party component or api out there?
Audio Libraries for MP3 editing
How do I merge/join mp3 files with c#
This code shows a way to make a CD
ripper in C#. There are APIs from some
vendors that allow reading audio CD
tracks but it is also possible to do
it using APIs that allow low level
access to CD drives such as ASPI from
Adaptec or IOCTL control codes. The
latter method is used in this case,
because there is no need to install
any third party software, it is
completely covered by Win32 API
functions.
http://www.codeproject.com/KB/cs/csharpripper.aspx
Splitting the MP3 stream will be difficult to do with any degree of precision. The compressed MP3 data exists as sequential chunks of audio data comprised of many samples. The easiest way to perform this would be to decode the stream either progressively or in its entirety, perform your manipulation, then re-encode it (which as I understand is how most jukebox software does it)
Having a solid knowledge of the file's binary format would be a good place to start. That done, you'll know what silence looks like in the file. You may have to define exactly what silence is. Presuming that, like most audio, it started from an analog source, there's almost certainly some noise buried in the "silence". What will your tolerance for ambient/background noise be?
Once you know what you're looking for, just scan through the file, looking for "it".
Simple ...
A program to do this already exists:
http://mp3splt.sourceforge.net/mp3splt_page/home.php
Related
I have a video analytics program that processes assorted frames from a video. (Several hours long)
The video is likely going to be an MP4 but may be other formats going forwards.
At the moment, I have a C# wrapper around an ffmpeg call to extract an individual frame at the requested time. (I'm using the ffmpeg.exe binary. Not the libraries directly)
At the moment, this all works. But it's slow. Very slow.
I've found ways to improve the speed by storing the extracted frames in a ramdisk while they're being processed. Changing the stored image format etc...
I just wanted to check if anyone could think of any way to pull individual frames out. At split-second accuracy.
I know this is probably possible with DShow etc... I went straight to FFMPEG as I've used it before. But if DShow is likely to be faster I'll gladly change!
In Windows you have native APIs to process, and in particular read from, media files:
DirectShow
Media Foundation
Both provide support for MP4 (H.264 video), DirectShow as a framework extended by third party MP4 Demultiplexer and H.264 decoder (of needed, also Windows 7 provides build it), and Media Foundation - natively or extended by third party extensions depending on OS version.
Both can be interfaced from .NET via open source wrappers DirectShow.NET and Media Foundation .NET respectively. This works out way faster then FFmpeg CLI for individual frames. Also note that you would be able to obtain frames incrementally without need to locate specific time and do excessive duplicated work, not even to mention process startup/initialization overhead. Alternatively you could use FFmpeg/Libav binaries through wrapper into C# and get similar performance.
You can change the position of the offset parameters. The order matters for the speed if the video contains valid meta data you can seek through the video faster.
If you put the offset before the input file the offset will be calculated with the bit rate with is not every time exactly (in case of a variable bit rate), but it is much faster. The correct way is to walk through the video (offset parameter is after the input file) but this takes time.
I want to develop a desktop application by programming in C# and using the .Net framework 4.
The goal of my application is to extract a MP3 audio stream from a supplied AVI file.
I have learned from the Internet that an AVI file is a container and it might contain different audio streams.
If the supplied AVI file contains one MP3 audio stream at least then I want to extract it and split it.
I want to split the MP3 audio stream into MP3 audio parts identified with a start time and an end time.
I have looked on the Internet for any .Net library I could use but without success.
Does someone know what documented .Net library would be useful ?
Maybe you can try this:
Simple C# Wrapper for the AviFile Library
It is targeted at AVI video but there might be some clues as how to use the same methods to extract the audio only.
Either use it as-is or use the example to incorporate what you need into your own code.
Since tools for this task already exist, I see no point in creating another one unless you're curious about how to do this yourself and learn something new.
If so, using a ready-made library would defeat the entire idea of learning something which is why I strongly recommend you try implementing the splitter yourself.
You can find descriptions of the AVI file format online, that should get you started.
Where I can found something suitable (library) for .NET 4.0 (C#) capable for following features:
+ Reading mp3/wav samples with direct access to samplebuffer of loaded samples? (for example I want to load mp3 sample and programatically add reverb, chorus, and more custom effects implemented by me)
+ Playing directly audio buffers (arrays of floats)
+ Saving audio buffers to disk as mp3 or wav
Some time ago i found ASIO for .NET and this only works with .NET 3.5, is there something for .NET 4.0? Thank's a lot for your help.
ASIO for .NET won't help you in the cracking of mp3 or wav files. The most modern API in Windows for doing this is Microsoft Media Foundation. These are all COM APIs though, so you're either going to be doing (perhaps painful) COM interop from .NET or (easier) writing a C++/CLI wrapper. If you go the C++/CLI wrapper, you will need to be aware of performance issues (especially with how critical latency is to audio programming).
I'm skeptical that you will get the audio latency you need when programming in .NET. A good audio driver (like ASIO) will get you down to <3ms of latency. So if you are targetting "live audio", you will need to be generating audio buffers quicker than that (unless you are fine with longer latencies). To put it this way, the "time intervals" that the Windows APIs deal with are in 100 nanosecond intervals :).
You likely don't want to have to crack the files yourself. It becomes tedious as it's not only just mp3 and wav. You also have to be aware of how the wav is formatted as well (to account for different bit rates, number of channels, etc.). Using Media Foundation, it will automatically load the write decoder for you, you just give it the file path. Check out this tutorial that shows opening an existing WAV file and writing a new WAV file. I just recently went down this path for a drum sequencer I'm creating, and it's not very painful at all (if you're familiar with COM programming).
The central component in MF that makes this possible is the MFSourceReader.
If you're wanting to play the audio after you modify it, you can look at the sample "RenderExclusiveEventDriven" in the Windows SDK (under "audio" I believe). That's what I did for the drum sequencer as well. Latency won't be an issue and you're just dealing with byte arrays, so manipulating the raw data becomes very easy. Though at this point, you can probably stick with the ASIO .NET route and just use that to play the raw data you get from MFSourceReader.
I don't think there are .NET wrappers around Media Foundation yet (though if somebody has done that work already, feel free to post here as it would be awesome to know).
I want to make a program which takes video and audio and merges them. Video type or audio type is not important for me. How can I make this? Does any library exist for this? I know there are many programs about this topic but I want to learn how to implement such a program.
The technical term for what you are trying to do is 'multiplexing', and commonly referred to as 'muxing'.
FFmpeg is a multiplatform command line tool that does this, and arguable the industry standard. Many projects wrap FFmpeg into libraries and GUIs.
FFmpeg is also open source, so you can download the code and see how they have done it. That siad, it is very big and complex.
If you are interested in the actual mechanics of muxing separate audio and video files together into a destination file, then you will need to learn much about container formats and Codecs.
Look at some sort of FFMPEG wrapper in C#.
An easy way to multiplex audio and video on linux is to use gstreamer. Here's a A/V pipeline that you can create using gst-launch on a shell prompt.
filesrc location=file1.vid ! queue ! mux. filesrc location=file2.aud ! queue ! mux. avimux name=mux ! filesink location=output.avi
Replace file1.vid with the name of your encoded video file and file2.aud with the name of your encoded audio file. output.avi is the container file that you need.
For an application I'm creating, I need to be able to read AAC and MP3 files and get the waveform data (not play it directly, I need to manipulate the data before playing).
Ideally, I should be able to read any MP3/AAC file out there (VBR, different bitrates, etc), or at least anything that could potentially show up in iTunes.
This last point is very important, as Chuck commented. I assumed iTunes would be MP3s, I didn't know they used AAC. In essence, I must be able to read anything that is in iTunes.
What approach do you recommend me to use?
What kind of libraries are out there?
This is for a commercial application that will run on Windows, written in C# 3.0. I can use Open Source libraries, but nothing with a license that will make me release my source code later.
Any pointers are greatly appreciated!
Take a look at mpg123 which is LGPL licenced.
There's also MAD, which is GPL but a commercial license can be negotiated.
For AAC there's FAAD2, but it is GPL. Not sure if other terms are available. Another source of enquiry might be checking the sources and licences used in this list of AAC software on wikipedia.