What has happened to the sound on YouTube?
YouTube was founded in February 2005 by Steve Chen, Chad Hurley and Jawed Karim, three former PayPal employees. The original purpose of YouTube was to provide a way for people to easily upload and share short video clips across the internet. The “Broadcast Yourself” motto drove YouTube’s initial growth, as users leveraged the platform to share slices of life, creative videos, and personal vlogs.
Over the years, YouTube has evolved into a hub for music videos and songs. As broadband internet became more widely available in the late 2000s, YouTube became a popular destination for listening to music. The ability to search for and stream music videos for free made it a disruptive force in the music industry. Today, YouTube has licensing deals with major record labels and is a dominant force in music discovery and consumption. Music charts based on YouTube data, such as YouTube Music Charts, reflect its importance for breaking new artists and tracking current listening trends.
Sources:
https://interestingengineering.com/culture/youtubes-history-and-its-impact-on-the-internet
https://filmlifestyle.com/when-was-youtube-created/
Compression for Streaming
Audio and video files contain a massive amount of data that needs to be compressed to make streaming over the internet feasible. According to the article “The important difference between audio and file compression” on Sound Guys, compression reduces the size of audio files by selectively discarding data that is least likely to be noticed by human ears [1]. This process removes inaudible data and redundancy from the original uncompressed audio, allowing large files like songs and videos to be streamed quickly and efficiently.
While compression enables streaming, it can negatively impact audio quality. The Sound Guys article explains that aggressive compression throws out more data, degrading the listening experience for some. Audiophiles argue compressed formats like MP3 lack the richness and subtle nuances of uncompressed formats like WAV and FLAC. However, for everyday listeners streaming audio and video, the convenience of compression usually outweighs any small reduction in quality.
The Loudness War
The loudness war refers to the trend starting in the 1990s of music being mastered to sound as loud as possible through dynamic range compression. With the advent of CDs, there was no longer a technical limit on loudness like there was with vinyl records. This led to an arms race among music producers to make songs sound as loud as possible to stand out on the radio and streaming playlists.
The downside is that excessive compression ruins the dynamic range of music, fatiguing listeners and compressing the sound into a wall of noise. Unfortunately, YouTube’s early audio algorithms rewarded louder music with higher placements in search results and recommendations. This encouraged masters tailored for streaming to be overly compressed to game the system, leaving little dynamic range. Music mastered quietly would often sound too soft on YouTube. This has trained a generation of listeners to prefer the distorted hyper-compressed sound of the loudness war era.
Normalizing Audio Levels
YouTube utilizes audio normalization and compression to help standardize volume levels across videos. Audio is analyzed and adjusted to hit a consistent target loudness, typically peaking around -14 LUFS (Loudness Units relative to Full Scale). This compression makes quiet sounds louder and louder sounds quieter to achieve more uniform perceived loudness (1).
The benefit of normalization is that it prevents viewers from being blasted by unexpectedly loud videos or having to strain to hear unexpectedly quiet ones. Overall, it can provide a more comfortable and consistent listening experience across YouTube (2).
However, heavy compression can be criticized for reducing audio dynamics, flattening emotion, and making music feel “squashed.” Additionally, normalizing audio based purely on loudness may overlook factors like genre, dynamic range, and artistic intent. Allowing creators some say over how their content is normalized could lead to better results.
In the end, reasonable normalization helps enhance the YouTube experience for most casual listeners. But options for creators and more nuanced approaches could satisfy both loudness consistency and audio quality.
(2) https://www.androidpolice.com/youtube-stable-volume-spotted/
Lossy Audio Codecs
Audio can be compressed using either lossless or lossy compression. Lossless compression reduces file size while maintaining 100% of the original audio quality. Lossy compression like AAC discards some data in order to achieve much greater reductions in file size, at the expense of some loss of quality.1
AAC and other lossy codecs take advantage of auditory masking, the phenomenon where sounds near other sounds are harder for the human ear to hear. The codec analyzes the audio and discards data from parts of the spectrum that are less audible. This allows the codec to heavily reduce the file size while aiming to keep the loss of quality imperceptible.
However, the more the codec discards, the more degraded the audio becomes. At very low bitrates, the lossy compression causes obvious artifacts and muffling of the audio. So while lossy codecs like AAC can produce small files, they inherently reduce audio quality compared to the original uncompressed audio.
Low Bitrate Streaming
One of the main factors impacting YouTube’s audio quality is the relatively low default streaming bitrate of 128kbps. This is significantly lower than the bitrates used for lossless CD audio, which is around 1,411kbps. Such a low streaming bitrate means YouTube audio contains less high frequency detail and lacks the dynamic range of lossless audio.
Specifically, the high frequencies above around 15kHz get cut off entirely at 128kbps. This removes a lot of the crisp detail and airiness from instruments like cymbals, acoustic guitar, and vocals. The low frequencies also suffer, with deep bass lacking punch and extension below around 60Hz. Overall the sound is much more compressed and narrow than a high bitrate source.
While necessary for accessible streaming across varying connections, the tradeoffs are quite noticeable on high fidelity systems. Given many listeners are now accustomed to compressed streaming audio, YouTube has little incentive to increase bitrates significantly. However, platforms like Tidal demonstrate consumer demand for lossless, CD-quality music streaming.
Differences in Playback
Audio quality on YouTube can vary significantly depending on the device used for playback. Laptop and desktop computers with good dedicated sound cards and speakers or headphones generally deliver the best YouTube audio quality. Smartphones and tablets are convenient for watching YouTube videos but have more limited playback capabilities.
Most modern smartphones and tablets can handle audio up to 48 kHz / 24 bit, which matches YouTube’s maximum streaming quality. However, the tiny speakers built into mobile devices severely limit sound reproduction. Headphones offer improved audio quality but may still be bandwidth limited on Bluetooth versions below 5.0.1
Dedicated external speakers connected to a phone or tablet via an audio jack or USB can improve YouTube audio playback quality. But the mobile device’s built-in digital-to-analog conversion and amplification stages remain a limiting factor compared to desktop playback. Ultimately, laptop and desktop computers with high-quality sound cards, digital-to-analog converters, amplifiers, and speakers or headphones deliver the best YouTube audio reproduction.
Listening Habits
YouTube has encouraged passive listening habits when it comes to music. Many people treat YouTube as a place to play music in the background rather than for critical listening. They put on playlists or mixes and let them run while doing other tasks, not paying close attention to the quality of each track.
As one Reddit user noted on r/YoutubeMusic, “In YouTube music, maximum audio quality you can get is 256 kbps AAC, which is equal to 320 kbps MP3 in terms of audio quality.”1 This level of compression is suitable for background listening but falls short of a high-fidelity experience. Other users complained of the poor recommendations from YouTube Music compared to Spotify. 2
With many people treating YouTube as merely “background noise,” there hasn’t been as much demand for YouTube to improve its audio quality. But this passive listening stance means people may be missing out on the full musical experience.
The Rise of Hi-Fi Streaming
In recent years, there has been a push towards higher quality audio streaming services that offer lossless audio quality. Services like Tidal have emerged to provide CD-quality lossless streaming to audiophiles and music enthusiasts. Tidal offers high fidelity streaming up to 9216 kbps, far surpassing the 320 kbps maximum bitrate of other popular services like Spotify and Apple Music.
As bandwidth speeds and storage capacity have improved, more consumers have begun demanding better than compressed, lossy audio quality for their streaming music. While the standard bitrate quality of sites like YouTube and Spotify may have been sufficient in the past, many listeners are now seeking out the highest fidelity experience possible. The success of Tidal and other hi-fi services demonstrates that there is a viable market for high quality streaming.
YouTube and other streaming platforms face increasing pressure to improve their baseline audio quality as consumer expectations rise. At a minimum, offering lossless CD-quality streaming could help YouTube better compete with specialized hi-fi services. Given YouTube’s resources and reach, they have the potential to significantly accelerate the adoption of high fidelity streaming if they choose to prioritize audio quality. The era of compressed, lossy audio may be coming to an end as demand for pristine fidelity streaming continues to grow.
YouTube’s Path Forward
There are a few key steps YouTube could take to improve audio quality on the platform:
Offer lossless streaming options. As noted in this MakeUseOf article, YouTube could introduce a lossless audio streaming option, similar to what other services like Tidal and Amazon Music offer. This would allow for CD-quality or better audio for discerning listeners.
Increase the default streaming bitrate. Currently, YouTube uses the AAC codec at 128kbps for audio in most videos. Increasing this default bitrate to 256kbps or higher would substantially improve audio quality for most listeners without significantly increasing bandwidth requirements.
Support uploading and streaming high-resolution audio and video files. YouTube currently converts all uploads to compressed streaming formats. Allowing content creators to upload lossless audio and high-resolution video masters would enable YouTube to stream higher quality versions in the future.
There are challenges to offering lossless streaming at scale, and concerns around increased bandwidth costs. However, with careful encoding and traffic shaping, YouTube could likely support lossless audio for many users. This, combined with increases to the default bitrate, would go a long way towards improving YouTube’s often lackluster sound quality.