
AIFF & AIFC
AIFF
Audio Interchange File Format (AIFF) is an audio file format standard that was co-developed by Apple Computer in 1988 based on Electronic Arts' Interchange File Format (IFF, widely used on Amiga systems) and is most commonly used on Apple Macintosh computer systems. The audio data in a standard AIFF file is uncompressed pulse-code modulation (PCM). There is also a compressed variant of AIFF known as AIFF-C or AIFC, with various defined compression codecs. Standard AIFF is a leading format used by professional-level audio and video applications, and unlike the better-known lossy MP3 format, it is non-compressed and lossless.
AIFC
The AIFC file is in fact an AIFF file designed to hold compressed audio data as well as uncompressed data. It is an extension of the AIFF file and was meant to replace it altogether. When a file is imported or exported from iTunes or Quicktime in "AIFF" format, it is actually AIFC that is being used. Pro Audio Converter is capable of creating AIFC files with lossless Linear PCM data as well as the following compressed data formats:
Here are some paramaters that can be configured when creating AIFF or AIFC files with Linear PCM audio data:
Sample Rate
Sample rate is the number of samples of audio carried per second, measured in Hz or kHz (1000 Hz). 44.1 kHz is the sampling rate of audio CDs and 48.0 kHz is commonly used for professional video. Higher sample rates result in higher quality audio with larger file sizes. Setting this to Auto will create an output file with the same sample rate as the input file. If the output file does not support the sample rate of the input file, Pro Audio Converter will use the greatest sample rate that is supported.
Bit Depth
Bit Depth defines the numer of bits (1's and 0's) used to represent each sample.
By increasing the bit depth, quantization noise is reduced improving the signal to noise ratio. For each 1-bit increment in bit depth, the S/N will increase by 6dB. 24-bit digital audio has a theoretical maximum S/N of 144 dB, compared to 96 dB for 16-bit. Audio CDs use a bit depth of 16 bits. 24-bit is common in professional audio and video environments.
Endianness
Endianness referes to the byte-order of each sample.
Big Endian stores the most significant byte first, and Little Endian stores the least significant byte first. By definition AIFF and AIFC files are always Big Endian.
Channels
This defines the number of audio channels contained in the output file. Setting this to Auto will attempt to create an output file with the same number of channels as the input file, if it is possible. You can also manually set it to output Stereo (2 channels) or Mono (1 channel).
Quality
The Good setting is optimized for the highest-speed encoding, for higher-quality choose Better or Best (optimal for 24-bit source). The tradeoff is between encoding speed and audio quality.