What is the Best Audio Codec for Online Video Streaming?
When we think of high quality sound in video streaming, we tend to first think about the visual aspect. However, while it should go without saying, the audio is just as if not more important. Without high quality audio, the viewer experience is massively degraded. What’s more, many people enjoy watching to live streams while on the go when they may not be able to watch at moments but can still listen. Furthermore, some people listen exclusively while attending to other things.
To get the best audio quality, you need the best audio codecs. In this article, we’ll cover the basics and help solidify your knowledge. We’ll detail what the best audio codec settings are for online video streaming to get the best sound quality. Additionally, we’ll discuss audio settings such as audio bitrate, channels and more.
Armed with this knowledge, you’ll better understand which audio codecs to use for streaming live video.
What is an Audio Codec?
The word “codec” is short for “coder/decoder.”
The term codec is a portmanteau that combines the words “coder” and “decoder.” A codec is a standard or tool for encoding and decoding multimedia files.
“RAW” or uncompressed audio files are recorded using techniques that capture as much audio data as as possible. This provides very high quality but results in very large file sizes that aren’t practical for live streaming
To make audio files smaller and easier to distribute, we use a codec.
The first thing a codec does is encode an audio file. This encoding involves tossing out extra information to reduce the file size in sizes while maintaining as much quality as possible. This process involves a sequence of complex mathematical functions.
The second role of a codec is decoding, which is essentially playing back an audio file that has previously been encoded. To make a complex process very simple, this means reversing the math done during the encoding step.
In short, an audio codec is a protocol for compressing digital audio to save space and for playing back with the video.
Common Audio Codecs
There are several common audio codecs available for use. However, MP3 and ACC are the most common.
There is a wide range of audio codecs available today. However, not all audio codecs are equally supported by audio devices.
Some devices may support one audio codec, but not another. Some provide better quality, while others focus on compression above all else.
These are important considerations when it comes to deciding on the best audio codec for a given situation. Let’s go over a few of the most common and best audio codecs.
The most well-known audio format is probably MP3, which is technically called MPEG-2 Audio Layer III.
Originally introduced in the 1990s, MP3 revolutionized digital audio. Files were much smaller than the previous audio formats used, allowing them to be streamed and downloaded over the internet.
MP3 also helped push the era of portable digital music past the CD era by enabling iPods and other early “MP3 players.” It is still widely used today.
Developed a few years after MP3, AAC built on the success of that format but increased compression efficiency.
AAC generally provides better audio quality at the same bitrate as MP3 or comparable quality at lower bitrates.
AAC has been upgraded several times. The latest version of the standard is HE-AAC. It is a closed source format but is probably the most widely used audio codec on the internet today. It is supported by most video streaming platforms
3. WAV (LPCM)
WAV, which is short for “Waveform Audio File Format,” was originally released more than 25 years ago.
It is known to be primarily used on Windows computers to store uncompressed audio in the LPCM format.
AIFF is a Mac format that’s similar to WAV. It stores uncompressed audio using the PCM (Pulse-Code Modulation).
Like WAV files, AIFF files are very large—around 10 MB for one minute of a standard audio recording.
Another codec on the market, albeit one that is becoming less common, is WMA—Windows Media Audio. This codec was developed as an alternative to MP3 but has become somewhat of a niche product.
The final audio codec we’ll take a look at is Opus. Opus isn’t in wide use yet, but it’s considered a next-generation codec. It provides higher audio quality at all bitrates compared to every other codec listed here. Opus also has the added advantage of being royalty-free and open source.
Both iOS and Android now natively support Opus playback. We’ll likely see Opus getting wider use in the future.
The Best Audio Codec
ACC is currently the best audio codec for professional broadcasting.
We believe that AAC is the best audio codec for most situations. AAC is supported by a wide range of devices and software platforms, including iOS, Android, macOS, Windows, and Linux. Other devices such as Smart TVs and set-top boxes also support AAC.
Besides wide support, AAC also has the advantage of better audio quality compared to MP3. Blind listening tests generally show that AAC is the best codec available for general use.
This may change in the future as Opus becomes more broadly supported. However, hardware and software changes move slowly. That day is likely still a few years away.
For internet video, AAC is the best audio codec for live streaming as well as video on demand. This is generally configured via settings in your hardware or software encoder
Recommended Audio Bitrate for Streaming
Bitrate refers to the amount of data contained in a digital media file per second of that media. Typically measured in Kbps (Kilobits per second), the audio bitrate can often be a stand-in for quality.
All else being equal, an AAC audio file that’s encoded at a bitrate of 192 Kbps will sound better than one encoded at 64 Kbps.
Our recommended audio bitrates for video, when using AAC, our recommendation for the best audio codec, are as follows:
- For 360p (low quality) video, use 64 Kbps audio bitrate
- With 480p and 720p video, use 128 Kbps audio bitrate
- For 1080p video, use 256 Kbps audio
Related Audio Encoding Settings
Aside from codecs, there are a number of other encoding settings that are important for the audio portion of any live stream or video on demand.
We’re going to briefly cover channels, audio sample rates, and video codecs.
Recommended Channels (Stereo vs. Mono)
You may also notice a setting for audio channels in your audio encoding settings. There will be two settings here: stereo, and mono. Mono refers to “one,” a setting that should be used only for low-quality video. Using mono reduces bitrate.
Generally, you should use stereo audio for all video recordings and broadcasts at 480p and above. This will provide a superior listening experience.
Recommended Audio Sample Rate
The sample rate is another setting related to audio quality. It simply refers to the number of audio measurements taken per second with a given recording. More samples per second will record a fuller, richer palette of tones, but will result in more data.
Generally, we recommend that you use 44100 Khz as the audio sample rate for all live streaming and online video. This is the standard for most audio equipment and recordings and will function perfectly.
H.264, also known as MPEG-4 Part 10, is a video compression standard for a high-definition digital video.
A live stream or online video requires more than the best audio codec settings. Obviously, video is crucial, advanced audio coding is as well.
To learn more about the best video codec for HTML5 live streaming, this post’s video codec counterpart.
Advantages and Disadvantages of Different Audio Codecs for Video Streaming
- Widely supported and compatible with many devices and platforms.
- Smaller file sizes compared to uncompressed formats, making it suitable for streaming and downloading over the internet.
- Paved the way for the popularity of portable MP3 players.
- Offers better audio quality compared to MP3 at the same bitrate.
- Supported by a wide range of devices and software platforms.
- Efficient compression, balancing quality and file size.
3. WAV (LPCM):
- Uncompressed format retains the highest audio quality.
- Compatibility with Windows-based systems.
- Similar to WAV, it maintains high audio quality with PCM encoding.
- Often used in Mac environments.
- An alternative to MP3, especially for Windows users.
- Offers a balance between audio quality and file size.
- Next-generation codec with superior audio quality at all bitrates.
- Royalty-free and open source, potentially leading to wider adoption.
- Lower audio quality compared to newer codecs like AAC and Opus.
- May not be the best choice for high-quality audio streaming.
- Closed-source format, limiting customization options for developers.
3. WAV (LPCM):
- Large file sizes are impractical for online streaming and distribution.
- Limited compatibility with non-Windows systems.
- Like WAV, it results in large file sizes.
- Less common and becoming somewhat niche, reducing compatibility.
- Limited current adoption, although this is expected to change over time.
Note: While these advantages and disadvantages provide a general overview, the choice of audio codec should be based on specific streaming requirements and compatibility with the target audience’s devices and platforms.
Feel free to integrate this section into your blog article to provide readers with a balanced perspective on the different audio codecs available for video streaming.
1. What is an Audio Codec?
Q: What does the term “codec” stand for? A: The word “codec” is a combination of “coder” and “decoder.” It is a standard or tool used for encoding and decoding multimedia files.
Q: Why do we need audio codecs for video streaming? A: Audio codecs are essential for compressing digital audio, making it more manageable for distribution while preserving quality. They also play a crucial role in decoding audio files during playback.
2. Common Audio Codecs
Q: What are some common audio codecs used for video streaming? A: Common audio codecs include MP3, AAC, WAV, AIFF, WMA, and Opus. Each has its unique characteristics and use cases.
Q: Which audio codec is considered a next-generation codec and why? A: Opus is considered a next-generation codec due to its superior audio quality at all bitrates and its status as royalty-free and open source. It’s gaining wider support for various platforms.
3. The Best Audio Codec
Q: What is currently the best audio codec for professional broadcasting? A: AAC (Advanced Audio Coding) is considered the best audio codec for most situations. It offers wide device and software support, including iOS, Android, macOS, Windows, and Linux, and generally provides better audio quality compared to MP3.
Q: Could the best audio codec change in the future? A: It’s possible that Opus could become more widely supported in the future, potentially altering the landscape. However, such changes typically occur gradually.
4. Recommended Audio Bitrate for Streaming
Q: What is audio bitrate, and how does it affect audio quality? A: Audio bitrate refers to the amount of data in a digital audio file per second, which correlates with audio quality. Higher bitrates generally result in better audio quality.
Q: What are the recommended audio bitrates for different video quality levels? A: For video streaming using AAC, it is recommended to use 64 Kbps audio bitrate for 360p video, 128 Kbps for 480p and 720p, and 256 Kbps for 1080p video.
5. Related Audio Encoding Settings
Q: What are some other important audio encoding settings to consider for video streaming? A: Other crucial settings include stereo vs. mono channels, audio sample rates, and video codecs.
Q: When should I use stereo vs. mono audio channels? A: Stereo audio is recommended for video recordings and broadcasts at 480p and above, as it provides a superior listening experience compared to mono.
Q: What is the recommended audio sample rate for live streaming and online video? A: It is recommended to use a sample rate of 44100 KHz for all live streaming and online video, as it is the standard for most audio equipment and recordings.
Q: What video codec is recommended for video streaming? A: H.264 (MPEG-4 Part 10) is recommended as the video codec for high-definition digital video streaming.
6. Final Thoughts
Q: Why is audio quality important for live streaming? A: High-quality audio is essential for an effective live streaming experience, and understanding audio codecs and related settings is crucial to achieving this.
Q: How can Dacast assist with live streaming? A: Dacast offers a professional-grade platform and services to help businesses worldwide get started with live streaming. They provide a free 14-day trial for testing their feature-rich platform.
Despite how important audio is for live streaming effectively, it’s not well understood. However, we’re confident that after reading this article you’ll better understand the principles of what makes high quality audio.
To recap, we’ve covered how audio codecs, audio bitrates and many other important componants such as the compression algorithm and transmission work together. Combined, the aspects we’ve discussed provide the best live streaming experience for your audience.
Did you know that Dacast helps businesses all over the world get started with live streaming? Our professional-grade platform and services can help you reach new heights using the power of live streaming. With our free 14-day trial, you can test drive Dacast’s feature-rich platform and experience the benefits for yourself.
Thanks for reading. We love to hear from our readers, so if you have any questions or experiences to share, let us know in the comments. For regular tips on live streaming, feel free to join our LinkedIn group…