Before we dive into this discussion, I want to first say that I will try to be more objective and less subjective about this particular topic. Personally for me, the larger the bitrate, the better sounding the music, of course. However, the purpose of this article is to explore the optimization of MP3 bitrates in accordance to their quality and file sizes.

First of all, if you don’t already know, there are two main types of bitrates: Constant BitRate (CBR) and Variable BitRate (VBR). As their names imply, CBR is basically MP3 encoding that has a consistent bitrate of data, no matter the situation and quality of the music/audio. In this form even the simplest silences and rests in music will be played back at the same bitrate as the most complex segments in a symphony. Thus, the general result is that CBR is simply non-efficient in memory usage.

Thus, to increase music encoding efficiency and to optimize MP3 file sizes, there is another form of audio encoding that follows the form of a Variable BitRate (VBR). To simply put it, VBR has a dynamic set of bitrates that change depending on the complexity of the music. Thus, the simpler the music form, the lower the bitrate as less data is needed to code for silence as opposed to high bitrates for many instruments and sounds being generated at once. To quote Wikipedia, “VBR allows a higher bitrate (and therefore more storage space) to be allocated to the more complex segments of media files while less space is allocated to less complex segments.” In general, when we encode MP3s as VBRs, the VBR that we select will be based on the average VBR as the mean of a music selection with actual bitrates oscillating above and below that value depending on sound complexities.

Now, onto actual differences in music qualities as a function of bitrates.

In the world of music encoding, there is a phrase know as “Near-CD Quality,” which basically refers to the fact that a piece of audio is encoded so well (and perhaps encoded to be lossless) that it sounds like music from a CD, which has very high qualities. Personally, I would say that MP3s coded around 320Kbps (CBR or VBR) is pretty much near-CD quality and pretty much sounds exactly like a CD. However, unless we’re all audiophiles, there’s not really a need to have all our songs stored with 320Kbps. However, we do want to obtain high audio quality while optimizing file sizes. Thus, after doing much research and speaking from personal experience, these are some of the basic MP3 audio bitrates and their experiences:

• 128–160 Kbit/s: Standard Bitrate quality – I personally use this for portable music devices to reduce file sizes.
• 192 Kbit/s: DAB (Digital Audio Broadcasting) quality – This is what I use for the MP3s in my music library. In my opinion, this strikes the perfect balance between size and quality.
• 224–320 Kbit/s: Near CD quality – Obviously, this has a really high quality, but is not optimal in terms of file sizes.

After reviewing through other articles online and polls about this topic, I believe that the general consensus is that A.) 320Kbps (CBR or VBR) is simply not worth the extra memory. However, 192 VBR and anything from 192Kbits to 256Kbits gives unnoticeable differences while improving file sizes.

[Do Higher MO3 Bit Rates Pay Off]

[Poll: What is the best MP3 bitrate for good quality with small file size?]