Download MP3 vs M4A (AAC-LC, AAC-HE v1, & AAC-HE v2) vs Opus Audio Quality Comparison MP3 Song Free

Official Description & Notes

xHE-AAC now beats HE-AAC v2 for the best codec at low bitrates! Watch (hear?!) me compare the two at 12 kbps and 24 kbps: https://youtu.be/74SsKOUHgvo

*64 kbps COMPARISONS*
0:00 WAV (1411 kbps)
0:18 MP3-64
0:36 AAC-LC-64
0:54 AAC-HE-v1-64
1:12 AAC-HE-v2-64
1:30 Opus-64

1:48 Difference MP3-64 vs. WAV
2:06 Difference AAC-LC-64 vs. WAV
2:24 Difference AAC-HE-v1-64 vs. WAV
2:42 Difference AAC-HE-v2-64 vs. WAV
3:00 Difference Opus-64 vs. WAV


*48 kbps COMPARISONS*
3:18 WAV (1411 kbps) (again)
3:36 MP3-48
3:54 AAC-LC-48
4:12 AAC-HE-v1-48
4:30 AAC-HE-v2-48
4:48 Opus-48

5:06 Difference MP3-48 vs. WAV
5:24 Difference AAC-LC-48 vs. WAV
5:42 Difference AAC-HE-v1-48 vs. WAV
6:00 Difference AAC-HE-v2-48 vs. WAV
6:18 Difference Opus-48 vs. WAV


*24 kbps COMPARISONS*
6:36 WAV (1411 kbps) (again)
6:54 MP3-24
7:12 AAC-LC-24
7:30 AAC-HE-v1-24
7:48 AAC-HE-v2-24
8:06 Opus-24

8:24 Difference MP3-24 vs. WAV
8:42 Difference AAC-LC-24 vs. WAV
9:00 Difference AAC-HE-v1-24 vs. WAV
9:18 Difference AAC-HE-v2-24 vs. WAV
9:36 Difference Opus-24 vs. WAV


*12 kbps COMPARISONS*
9:54 WAV (1411 kbps) (again)
10:12 MP3-12
10:30 AAC-LC-12
10:48 AAC-HE-v1-12
11:06 AAC-HE-v2-12
11:24 Opus-12

11:42 Difference MP3-12 vs. WAV
12:00 Difference AAC-LC-12 vs. WAV
12:18 Difference AAC-HE-v1-12 vs. WAV
12:36 Difference AAC-HE-v2-12 vs. WAV
12:54 Difference Opus-12 vs. WAV


I decided to make a follow-up video to a previous one where I compare MP3 and M4A ( https://youtu.be/-wg6LjhfHZ8 ). I will acknowledge a few errors in judgment with the previous video. In that video I compared the formats at 320 kbps, which was really quite pointless because most people can't tell the difference at that bitrate and YouTube compresses audio to about 128 kbps anyways. In this video, I compare the formats at lower bitrates (64, 48, 24, and 12 kbps). In my previous video, I found the difference between the MP3 and M4A, which was misleading because you can't tell which audio was lost from each format. A better comparison is to find the difference between the lossless source (WAV) and each lossy format, which I do in this video.

The technique to find the 'difference' between the WAV and each compressed format is the same as used in this video... https://youtu.be/MmecPiKClHk

FIVE THINGS TO NOTE:

[1] Spectral band replication (SBR) discards the top half of the audible spectrum when encoding. The discarded audio is then "predicted" based on the bottom half of the spectrum when the file is decoded. Some side information is added to the file to assist with the reconstruction of the upper frequency band. At low bitrates, higher quality can be achieved since only about half of the data needs to be encoded. At higher bitrates, however, files with SBR can sound worse since the upper half of the spectrum is "fudged" when the file is played back. For more details, visit https://en.wikipedia.org/wiki/Spectral_band_replication

[2] Parametric stereo (PS) collapses the audio to mono when it is encoded. Some side information is added to the file to provide the decoder with instructions on how to pan frequency bands when the file is played back. At low bitrates, this technique can increase quality since only one channel needs to be encoded. At higher bitrates, however, files with PS can sound worse since the stereo image is "fudged" upon playback, much like the upper band is with SBR. For more details, visit https://en.wikipedia.org/wiki/Parametric_Stereo

[3] Strangely, the 64 kbps AAC-HE v2 has a bandwidth of ~16 kHz while the 48 kbps AAC-HE v2 has a bandwidth of ~20 kHz (this can be seen in the video). Thinking it was an error, I encoded the files again and got the same result. I am assuming that the 16-20 kHz band of the 48 kbps file only contains distortion/compression artifacts.

[4] MP3 files were encoded with LAME v3.1, all AAC variants were encoded with Nero AAC Codec 1.5.4, and Opus files were encoded with Opus Audio Encoder v1.3.1. I used the program fre:ac to assist me with the encoding process. The bitrate stated in the video is the bitrate the encoder was set to. I used average bitrate mode for all formats, so the actual bitrates of the files deviated slightly from what is stated.

[5] YouTube recompresses video and audio after they are uploaded, reducing the quality slightly. The original audio files used in this video are available at https://drive.google.com/open?id=15aBgEsJtUJ76weeBQV7Szh9A8jgo0bkA

The music used is this video is "Give It Up (Start Again)" by Snowflake feat. Subliminal. The track is licensed by Creative Commons. Download it for free at https://bandcamp.musikpiraten-ev.de/track/give-it-up-start-again-feat-subliminal

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