AAC Vs. MP3 Bitrate Equivalent
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AAC and MP3 are the two most prolific audio formats. Both offer a compromise between sound quality and file size, especially in the choice of bitrate. This can obscure their benefits, so how do the bitrates of each format compare to each other?
AAC and MP3 audio at equivalent bitrates are similar, but AAC is able to achieve higher fidelity for a given bitrate. AAC is an improvement on the MP3 codec, built to be its successor. It is generally a better format at any given bitrate than MP3, compatibility aside.
Both AAC and MP3 have their ups and downs. While AAC may offer superior sound quality, MP3 is still widely supported and used. There are many other factors you may need to consider, among other alternatives.
AAC Vs. MP3 At Equal Bitrate
AAC (Advanced Audio Codec) is technically superior to MP3 (MPEG-I Layer III). AAC typically gives similar or better results than MP3 at a given bitrate. AAC was developed as a successor to MP3, building off of the work leading to the development of MP3 while avoiding key pitfalls.
MP3 is among the most widely supported audio formats and is the most popular. Suppose you use old MP3 players or very old phones. In that case, you may be stuck with it. Make sure to stick with as high a bitrate as you can store if audio quality is a priority. Otherwise, if you use modern devices, there is usually no need for MP3, and other formats such as Opus or AAC are better, should you get the choice.
The Apple ecosystem is notable here for supporting AAC, ALAC, and AIFF over formats more common for other platforms, such as MP3, FLAC, and WAV. iTunes, in particular, is known to be picky regarding formats that are otherwise industry-standard.
Comparing Sound Quality: AAC Vs. MP3 At Different Bitrates
The difference in the sound quality of AAC and MP3 varies across different bitrates. In general, AAC offers better fidelity, but this is often a surprisingly negligible factor.
At a bitrate of 128 kbps and lower, an AAC file will usually sound better than an MP3 file of the same bitrate. However, as you compare higher bitrates, the difference in sound quality between the two formats becomes less noticeable. At 256 kbps or higher, the difference in quality between AAC and MP3 is minimal to the point that it’s difficult for the average listener to tell the difference.
This is only a rule of thumb. Differences in sound quality can also be affected by the following:
- The content of what you’re listening to, as formats encode, sounds better than others.
- The recording equipment or audio mastering is poor, as the information is bad.
A modus operandi in the distribution of audio is MP3 files encoded at 256 kbps or 320 kbps. This is at the point where transparency is reached, and so the effect of the lossy compression is hardly perceptible, and using AAC instead would inconvenience the occasional user with compatibility issues.
Storage is not at the premium it was back in the 1990s, so sticking with high bitrates is usually easier than worrying about the differences between codecs, features, and compatibility permitting.
The Technical Advantages of AAC Over MP3
AAC sets itself apart from MP3 in a variety of ways, including the much-improved encoding:
- AAC scraps the FFT component of MP3’s encoding process, using only MDCT
- AAC increases the encoding block size for gains in data efficiency
- AAC uses a more efficient and simpler filter bank
- AAC encodes higher frequencies much better
- AAC is far more modular, giving codecs more room to optimize encodings
AAC’s improvements over MP3 did not stop at the encoding of data:
- AAC supports a broader range of sample frequencies
- MP3 only supports mono, stereo, and 5.1 channels, whereas AAC allows for 48 channel
Overall, if the choice is yours, AAC is the better pick. However, keep in mind that if you already have an MP3 file, converting it to AAC won’t recover anything that MP3 lost. It’s usually best to avoid converting between lossy codecs unless necessary for compatibility.
Understanding The Purpose Of AAC and MP3
The AAC and MP3 formats are similar in many ways, which helps put their use and trade-offs into perspective and why the difference can be important. To do so, it’s helpful to understand what audio quality and bitrate really mean.
What Does Audio Quality Mean?
Audio quality is generally equivalent to audio fidelity, which is the degree to which the audio is faithful to the original sound. Poor fidelity is thus a poor capacity to recreate the sound. To play sound back accurately, we need as much information about the original sound wave as possible.
What Does Bitrate Mean?
Second, bitrate is the number of bits per unit of time. This can be measured in kilobits per second (kilo means 1000) or kbps. The length of a given track isn’t changed significantly between formats, so the bitrate is proportional to the amount of data. Hence, a higher bitrate means a bigger file.
What Does This Mean For AAC and MP3?
We want AAC- and MP3-encoded data to hold as much information as possible while minimizing the amount of data we need to store that information. An essential insight into MP3 and AAC is that both are lossy formats. More specifically, both use information-discarding compression to reduce audio file size. This is why some MP3 files sound worse than others: some hold more information.
Both the AAC and MP3 formats use algorithms that eliminate unimportant information. Unimportant information doesn’t affect what you hear much. The lower the bitrate, the fewer data the MP3 or AAC encoder has to work with, so the more it will need to throw away. There is a soft limit to how well you can do this, and it involves many compromises.
AAC makes these trade-offs better than MP3. The engineers and scientists working on AAC found many flaws in MP3 and improved and expanded upon them to create the AAC standard. As a result, you will often find that even though the bitrates of an MP3 file and an AAC file might be similar, the AAC file can store more useful information and will thus sound better.
Opus: The Best Lossy Codec
For most purposes, Opus (the codec) is the best general-purpose lossy codec available by the ratio of quality to bitrate. You can do better than AAC if you’re less worried about compatibility. Ogg Opus (the file format) has garnered much more support since its standardization in 2012, but most people haven’t heard of it.
Opus is a successor to Speex, a special-purpose codec for speech. Xiph and the open-source community, as a free and open standard and reference implementation, develop Opus.
On the other hand, is it that much better than AAC? No. The difference between AAC and Opus is far smaller than the difference between AAC and MP3 for bitrates around and below 128 kbps. Diminishing returns are available to newer codecs, so don’t expect them to take off without the push of large content platforms.
Family Compatibility: MP3’s Support Vs. AAC’s Advanced Codec
When it comes to compatibility, MP3 and AAC are like that one weird uncle and the tech-savvy cousin at your family reunion. Sure, they’re related, but they go about things differently.
MP3 is like that uncle who’s been around forever and is a staple at family gatherings. His format has been around for decades and is supported by almost every device on the market. From your grandma’s old CD player to the newest smartphones, MP3 is the format that’s always invited to the party.
On the other hand, AAC is like the tech-savvy cousin of the next generation and is constantly experimenting with the latest gadgets and apps. He’s the newer, more advanced codec that offers better sound quality and smaller file sizes. But he still needs to be more widely supported than MP3 and might not be compatible with older devices.
So, do you want to play it safe and stick with the uncle everyone knows and loves, or take a chance on the tech-savvy cousin? It’s all about considering the pros and cons and deciding which is best for your specific needs and preferences.
Conclusion
The choice of audio format in a modern context is generally a personal preference. When bitrates are high and modern platforms support both, it won’t affect the average user much. However, for those looking to get a bit more out of every bit: stay well away from MP3.
References
Various views on the topic: quora.com | superuser.com | hydrogenaud.io
Writing ideas on MP3 and ACC bitrate: lifewire.com | tritondigitalcommunity.force.com | multimedia.easeus.com
Ideas on ACC compared to MP3: whathifi.com | winxdvd.com | diffen.com
