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It is said, that MP3 frame contains 1152 samples. What is a "sample" then? A pair of values for right AND left channel? Or an individual value fro right OR left channel?
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Audio sampling is the process of transforming a musical source into a digital file. Digital audio recording does this by taking samples of the audio source along the soundwaves at regular intervals.
mp3 Basic Tips Use either 22.05kHz or 44.1kHz (44.1kHz is CD quality and recommended) sample rate. Other sample rates will playback in some players incorrectly, typically making you sound like one of the Chipmunks.
MP3 is a digital sound format, and digital waves are represented as square waves, like each step in a staircase. The higher the sampling rate, the more steps used to approximate the curve, and the closer the digital signal sounds to the original sine wave.
A Sample Rate of 44100 Hz and a Bit Depth of 16/Bit Rate of about 320 kbps is known as the Red Book standard for audio CDs.
The language that is used can get a little bit confusing. The just of it is that each frame will have 1152 (or 384, or 576 depending on MPEG version and layer) per audio channel. How that data actually gets stored is more complicated than a single value for each channel because of compression.
If you want to learn more I would recommend http://blog.bjrn.se/2008/10/lets-build-mp3-decoder.html for a nice, detailed blog that builds up the reader's understanding of the MP3 format for the sake of building a decoder.
You can also see http://wiki.hydrogenaudio.org/index.php?title=MP3#Polyphase_Filterbank_Formula for rather technical information. Link is anchored to a section that says specifically: "Audio is processed by frames of 1152 samples per audio channel" But the whole page describes aspects of the MP3 format.
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