Audio files conversion

The application must perform one of the specified activities on every audio file which is located in a certain folder and all subfolders. The results should be saved into the other given folder and create the same structure of subfolders. • Audio files will be in wav format. • It is necessary to support all PCM formats: 8-96 kHz, 8 bit (lin/A-law/u-law) - 16bit lin, mono/stereo. The offer must contain the information which conversions will support stereo (mandatory for conversions 1, 2, 3, 6 and 7). • Tool should be written in C++. • The version for GCC (4.8 or later) and for MS Visual Studio as well (12 or later) is required. Project files should be provided to enable compiling without additional effort. The same goes for external tools accompanied with the source code. If only the executable version of the external tool is used, it should be provided for both Linux and Windows. • The application should be well-written and well-documented, both regarding its use and its source code. Supply plenty of test samples. The following conversions should be provided: 1. Resampling recordings to different sampling frequency (e.g. from 22kHz to 16kHz). Of course, the application of anti-aliasing filter is compulsory. All the other conversions mentioned do not require the change of the sampling frequency. 2. Speedup of the recordings by simply omitting the samples. Besides the speedup, the expected effect is the pitch increase and the spectrum expansion. Speedup should be set in a range that can also be decimal (e.g. 0.4 – which represents the actual length of the file compared to the initial one). 3. Slowing down the recordings by inserting and interpolating samples. Similar comments can be applied here as for the aforementioned point. These two points could be combined into one, with the speed down coefficient being bigger than 1. 4. Speedup and slowdown of the recordings without pitch and spectrum change. Since this is a bit more complex technique, the use of other (free) tools is acceptable, preferably with the source code. This goes for all other transformations as well. 5. Application of a certain compression to the recording and its returning to the original format (wav), with deformities made by the compression. Minimally support the majority of codecs at [login to view URL], as well as mp3. 6. Noise application to all recordings. The noise signals (corresponding wav files) will be available in a separate folder (and its subfolders). These should be selected in random manner. Signal-to-noise ratio (SNR) is an input parameter and it is necessary to make sure that it is always maintained (by changing the intensity of the noise applied). 7. Conversion by applying external tool which would be supplied. So, the application should use that external program for every file which needs processing.