Can FFMPEG or any other project detect an audio file contains only noises? - audio

I have a batch of audio files which recording people's voice. But some of this audio files record only noises or microphone burst. I want to detect these files and jump over them while processing my program.
I'm not sure whether ffmpeg can do this. If yes, could you guys provide me a link of that method? If not, do you know if there is some other software can do this? Or do you have any solution or suggestion to this problem?
Thank you.

I would approach this by looking at peak values and duration. SOX is a program that allows shell scripting which could batch analyze this. There is a large user base and forum as well.
Here is a link to a forum topic discussing it's use on batch discovering peak values and outputting information to a .csv file.

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Linux Audio record and quality comparison

I am starting a project to test the audio performance on linux.
What I need to do is to play the audio on our websystem and check the audio quality (or just check it has audio output) on linux.
I am going to record the audio on linux with ffmpeg. Is there any other better choice?
I don't know how to (automation) check I recorded is what I played, as well as the quality of recorded audio.
I think what you need is PESQ (Perceptual Evaluation of Sound Quality). However I have not found anything which is open source/free and out of the box.
You can download the recommendation from here:
http://www.itu.int/rec/T-REC-P.862-200511-I!Amd2/en
Basically this is the reference implementation of PESQ.
Sevana has an audio quality analyser which is not an ITU standard, it is AQuA:
http://www.sevana.fi/aqua_wiki.php
It is available for linux but I think you have to pay for it.
You can also check the similarities for two audio files with cross-correlation, please refer to here:
https://dsp.stackexchange.com/questions/736/how-do-i-implement-cross-correlation-to-prove-two-audio-files-are-similar
I just learned that lot of people are using Matlab or Octave to generate the necessary data, for example:
http://bagustris.blogspot.ie/2011/11/calculate-time-lag-from-cross.html

automatically trim audio files

I'm trying to extract snippets (3-5 sec.) from a large collection of audio files.
I would like to do this with a shell script. I found basically nothing on the internet, so I'm asking here.
I'm also familiar with perl, php and java - I don't care what language will do, I just want to job done :)
Scenario: I got a large archive of audio files in very high resolution. I need to extract a very short snippet in low resolution for a preview (3 to 5 sec. is extremely short but that's what we need). Being a huge fan of shell scripting, I was hoping to automatize a process that extracts the snippet at RANDOM onset time... is it really too much to ask? :)
Thank you for your ideas!
You can use flash to automatically set lengths on the audio according to this blog:
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/media/Sound.html
Hope it helps.

Searching for audio

I am looking for a toolkit or library to search contents of audio files for am audio sample.
For example I have 5 seconds of speech that I know it exists in hundreds of hours of audio, and I want to find exact file and position of this sub-samples.
The sample is %99 similar but maybe converted to different audio format so it may have minor differences in waveform.
I prefer .NET library if there is such an option.
Thank you.
What you are trying to do is not an easy DSP problem to solve, and there is no one foolproof method. There is however an excellent recent article on audio fingerprinting on codeproject which goes into some depth on an algorithm that searches for duplicate MP3s, with code in C#. You may be able to adapt the algorithm to your needs.

Finding audio peaks in video files

I have a bunch of video files that I want to process. I want to write a program that can find the audio peaks in each file and return the times where those peaks occurred.
I've looked for a lot of different APIs in different languages but couldn't get any of them to work. I am partial to php and java, so if anyone knows any good audio processing libraries in those languages that would be great! But really I don't care too much about the language. I will need to run this program on a cron.
Also, is it possible to use system calls to ffmpeg from within a script to accomplish this? Thanks in advance.
While I've only used this to work directly with audio files, the python wrapper around theechonest's audio analysis service can slurp in the audio from various video files. It uses ffmpegs shared libs to do this, though I find this wrapper much easier to work with via python then the command line.
Of particular interest within the api is echonest.video which is, to quote the docs:
Framework that turns video into silly putty.
I'd add a couple other helpful urls but apparently I can only add one since I don't have a reputation...
anyway, hopefully that's a helpful lead.

Is there open source audio feature extraction software avaliable?

I undertaking a personal project which involves the development of a system which will automatically generate audio thumbnail clips (about 30 seconds in length) from a full length track.
In order to do this I want to look at the energy and pitch of the audio to try and correctly identify its major structural features.
Is there any open source software available that can do energy/pitch extraction? If not I will start looking into alternative methods using MATLAB.
Thanks!
YAAFE (Yet Another Audio Feature Extractor) http://yaafe.sourceforge.net/ does audio feature extraction in MATLAB, Python and C.
You might want to look into the Echo Nest API. It has a lot of audio analysis capabilities, and I know there's a script bundled in the Remix package that can automagically turn songs into shorter or longer versions (I believe the script is called earworm).
Audacity may do it.
Try JAudio which can extract features from an audio.
MARSYAS contains bextract for analysis, can find MFCCs and various other timbral and spectral features. http://marsyas.info/

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