Do Audio Converters Make A Difference?

Quality matters when converting audio files. This remains an issue when converting between digital and analog audio representations. But time and effort are valuable too. After all, is it worth the extra effort or cost to increase conversion quality?

File format audio converters may vary in their choice of codec, which leads to different encoding qualities. However, the practical distinction between most formats’ modern codecs is typically negligible. Dedicated analog/digital audio conversion hardware isn’t worth it for the average listener.

The role of codecs in file format conversion varies significantly, like between MP3 versus Opus versus WAV. On the hardware side, the priority afforded to A/D converters differs, but the situation has evolved remarkably. These two sides of the audio conversion coin are covered in parts one and two.

Part I: Do Audio Codecs Make A Difference?

The choice of audio codecs for a given format conversion can sometimes make a significant difference. However, this varies by format, compression methods, bit rates, the track itself, and more. All audio conversion tools use codecs behind the scenes, although some are more transparent about which they use compared to others.

Codecs are routines that allow for the encoding and decoding of audio data to and from a particular format. These are software programs or “libraries” that media players and converters use to support different audio formats. The developers will often provide a reference codec, although third parties may offer competing options as well, especially for popular formats.

When Are Audio Codecs Important?

Audio codecs matter most when the encoding process is nontrivial. For example, WAV contains raw, uncompressed, linear audio samples. This makes it very simple, and thus the differences between encoders will be next to nothing.

On the other hand, lossy compression is a tough tradeoff between saving as many bits as possible and sacrificing as little audio quality as possible. This is challenging to get right over a practical range of sounds, and leaps and bounds have been made since MP3 started making waves – pun intended.

The two most popular formats employing lossy compression for consumer use are MP3 and AAC. Other formats, such as Opus and Vorbis, also have various implementations of their respective standards. However, the variation for Opus is lower: both libopus and FFmpeg are modern.

The Differences Between MP3 Codecs

The original release of the MP3 format was a specification. It  was (cleverly) stringent about the nature of the decoding process but left much of the encoding up in the air. This has allowed for many significant encoding improvements over the years while maintaining compatibility with the MPEG standards.

The specification used patented algorithms and techniques. Therefore, producers of the codecs would need to obtain a license. One patent owner was the Fraunhofer Society, releasing the first available software encoder L3enc. Previously, only prohibitively expensive hardware encoders existed. The program was shareware, but it locked higher-bitrate encoding behind a $250 fee.

Many companies would develop applications and tools to encode and decode MP3s, but one notable project stood out. LAME (standing for LAME Ain’t an MP3 Encoder). Contrary to its acronym, it is an open-source MP3 encoder. But it was initially released in 1998, before the patents encumbering MP3 expired. Thus, LAME claimed to merely be an educational demonstration of how to make an MP3 codec and was distributed as source code only.

LAME received its first stable release in 2017, soon after the last of MP3’s patents expired, and it outperforms L3enc and the “gold standard” successor, MP3enc. With its improved psychoacoustic model, better default parameters, and implementation of more advanced features like VBR, it is used in many different programs, such as FFmpeg and Audacity.

Unfortunately, it’s challenging to find out which encoders are used by most commercial software or cloud conversion services. However, as an example, the VLC media player employs its own MP3 codec. Still, the VLC wiki recommends LAME as a better alternative for creating/converting to MP3 files.

The Differences Between AAC Codecs

AAC is another popular format, developed as a successor to MP3, and serves as one of the best lossy audio formats. AAC was similarly developed at a joint effort. While supported across all major platforms, it has seen particularly high adoption within the Apple ecosystem.

AAC’s main codecs include

  • Apple AAC, the codec integrated into Apple operating systems (available for Windows)
  • Fraunhofer Development Kit AAC codec (cross-platform)
  • Fraunhofer “FgH” AAC codec (binary-only distribution under Winamp for Windows)
  • FFmpeg AAC codec (cross-platform and open source)

These are roughly in order of quality of the results (ratio of fidelity against compression). On the other hand, they should give similar results in constant bit rate mode. Note that FFmpeg has poor variable bit rate AAC support.

Once again, it’s tough to know which codecs are used by a user-friendly converter. Often this information isn’t public, or they may implement their own codec. If you need the best results, learn how to take advantage of the best codecs directly. Otherwise, trying a few converters and comparing the results is best. Although, without good audio equipment, the difference may be inaudible.

What Actually Makes A Difference To Audio Conversion?

Unless you have the appropriate Hi-Fi equipment, the difference between modern encoders will often be hard, if not impossible, to hear. Crucially, however, you will find that you’ll get very different results when using other converters. So what’s going on here?

Different encoders use different default settings. One of the most important settings is bit rate – the amount of data used for the audio stream per second. For example, 128 kilobits per second or 128 kbps (kilo- means “thousand”). The more bits, the more information you keep, thus the better the quality. However, the file will be larger.

Typical bit rates vary between 64 kbps (relatively poor quality) to 320 kbps (well within transparency, where perceiving the loss is nearly impossible). Many converters will allow you to configure the bit rate. These days, we have a lot more space to store files compared to the 1990s, so it’s recommended to err higher for better results.

Part II: Do A/D Audio Converters Make A Difference?

A/D (Analog/Digital) audio converters are typically dedicated hardware devices that convert streams of digital bits into analog signals or vice versa. Your computer, phone, and other playback-capable devices already have one built-in.

However, unlike the small chip that likely costs manufacturers a few cents apiece, dedicated audio converters can be bought for hundreds of dollars. Are they worth it?

The Differences Between A/D Audio Converters

The quality difference between modern A/D audio converters is generally small. With consumer setups, some enthusiasts might find that a dedicated sound card in a desktop PC, combined with high-end headphones, will give them improved results. However, A/D converters are usually not the weakest link.

In fact, A/D converters are generally a low priority even for audio professionals with complex audio processing pipelines – cables running between separate, dedicated hardware to perform each step with high fidelity in real-time.

While the one in your phone likely isn’t going to cut it, it’s often not worth going for a high-end converter over upgrades to other hardware, even if you’re a serious audiophile or produce music. Typically, the differences are primarily in their features once you start looking higher than mid-grade devices.

Conclusion

Generally speaking, as long as you’re using modern conversion software and devices, the average listener, and even casual audiophiles, won’t stand to gain much from being picky about codecs. Instead, your choice of format and bitrate are far more consequential.

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