16/03/2007, 03:51 AM
This guide is in no way an accurate one. At best, this can only be used as a rough comparison, and general guide.
If you want better comparisons, search for those public double-blind test results.
If you want better comparisons, search for those public double-blind test results.
I decided to test various audio codecs to find out what are ideal quality settings to use. Note, as said above, this isn't accurate. At times, I've even had discrepancies with my own results :S
Just a few notes though:
- I've only tested using one song, which happens to be a 192kbps MP3. This is definitely not a good choice of source, but is fine for my purposes - that is to test codecs at low bitrates
- I'm using the PSP headphones (not a good set of headphones to test either)
- When the encoder offered an option between speed and quality, the highest quality setting was always selected.
- The source file being an MP3 one, the results may favour MP3s...
- This is still somewhat incomplete
Constant Bitrate (CBR) Tests
(out of the two encoding methods, CBR is the most basic and provides the worst compression. However, it's useful for comparison purposes (compatibility shouldn't be an issue) - ie providing a general idea of which codec is better)
Note that OGG Vorbis doesn't support CBR encoding, thus it's not included here.
Encoder/Settings | Bitrate (kbps) | Rating |
Original MP3 file | 192 | 100% |
MPEG-1 Audio Layer 3 (MP3) (Note, JS = Joint Stereo) | ||
LAME (JS) | 64 | 30% |
LAME (JS) | 96 | 70% |
SoundForge (JS) | 112 | 65% |
LAME (JS) | 112 | 80% |
SoundForge | 112 | 60% |
LAME | 112 | 75% |
SoundForge (JS) | 128 | 90% |
LAME (JS) | 128 | 90% |
SoundForge | 128 | 90% |
LAME | 128 | 90% |
WMP 10 | 128 | 90% |
iTunes (JS) | 128 | 82% |
iTunes | 128 | 71% |
SoundForge (JS) | 160 | 100% |
LAME (JS) | 160 | 100% |
SoundForge | 160 | 100% |
LAME | 160 | 100% |
Windows Media Audio 9 Note: the "professional" codec has VERY limited support | ||
WMA9 Std | 96 | 55% |
WMA9 Std | 128 | 94% |
WMA9 Pro | 128 | 95% |
Advanced Audio Coding, Low Complexity (LC-AAC) Note: I found Nero's encoder produced better quality than CT's. But CT did produce better sounding bass than Nero's, but I felt that Nero produced overall better sound. | ||
CodingTechnologies | 64 | 60% |
iTunes | 64 | 64% |
Nero | 64 | 64% |
CodingTechnologies | 80 | 70% |
iTunes | 80 | 72% |
Nero | 80 | 72% |
CodingTechnologies | 96 | 83% |
iTunes | 96 | 85% |
Nero | 96 | 85% |
CodingTechnologies | 112 | 88% |
iTunes | 112 | 90% |
Nero | 112 | 92% |
CodingTechnologies | 128 | 96% |
iTunes | 128 | 97% |
Nero | 128 | 97% |
Advanced Audio Coding, High Efficiency (HE-AAC) | ||
Nero | 24 | 60% |
Nero | 32 | 68% |
Nero | 48 | 88% |
3GPP | 48 | 85% |
CodingTechnologies | 48 | 86% |
Nero | 64 | 92% |
CodingTechnologies | 64 | 92% |
Nero | 80 | 94% |
CodingTechnologies | 80 | 94% |
Nero | 128 | 98% |
CodingTechnologies | 128 | 98% |
HE-AAC with Parametric Stereo (HE-AAC v2) Note, PS seems to increase the quality of HE-AAC only at extremely low bitrates. At higher bitrates, I found that it changed the sound way too much, and actually _reduced_ the quality | ||
Nero | 16 | 40% |
Nero | 24 | 65% |
Nero | 32 | 70% |
Nero | 48 | 72% |
3GPP | 48 | 85% |
CodingTechnologies | 48 | 74% |
Nero | 64 | 73% |
Adaptive Transform Acoustic Coding (ATRAC3plus) I only bothered testing this codec actually because the PSP supports it | ||
SoundForge | 48 | 45% |
SoundForge | 64 | 82% |
SoundForge | 96 | 84% |
SoundForge | 128 | 88% |
SoundForge | 192 | 92% |
Variable Bitrate (VBR) Tests
(VBR will typically produce better quality sounds than CBR with about the same filesize. There are usually two methods, VBR (quantizer/quality) and ABR (average bitrate). VBR will produce better results than ABR, so I've usually opted testing VBR (ABR gives better control over filesize))
Note, the average bitrate is a simple filesize ÷ time calculation.
Quality Setting | Av. Bitrate (kbps) | Rating |
MPEG-1 Audio Layer 3 (MP3) (Note, JS = Joint Stereo) | ||
SoundForge (JS) | ||
15% | 89 | 72% |
20% | 93 | 74% |
50% | 121 | 89% |
75% | 160 | 90% |
LAME (JS) | ||
Q9 | 89 | 75% |
Q8 | 100 | 89% |
Q7 | 109 | 90% |
Q6 | 114 | 92% |
Q5 | 121 | 95% |
Q4 | 145 | 100% |
Q2 | 184 | 100% |
Windows Media Audio 9 Note: the "professional" codec has VERY limited support | ||
WMA9 Standard | ||
75% | 108 | 88% |
90% | 169 | 98% |
98% | 270 | 100% |
WMA9 Professional | ||
75% | 98 | 93% |
90% | 140 | 98% |
98% | 216 | 100% |
OGG Vorbis (OggEnc2) | ||
Q-1 | 43 | 71% |
Q0 | 59 | 88% |
Q1 | 77 | 99% |
Q2 | 85 | 99% |
Q4 | 126 | 100% |
Advanced Audio Coding, Low Complexity (LC-AAC) | ||
Nero | ||
20% | 87 | 86% |
25% | 106 | 90% |
FAAC | ||
"100" (out of 500) | 128 | 96% |
Advanced Audio Coding, High Efficiency (HE-AAC) (Nero) | ||
7% | 21 | 55% |
15% | 40 | 88% |
20% | 50 | 90% |
25% | 63 | 92% |
50% | 112 | 92% |
Yeah, there's quite a few odd results in there, but oh well.
Sound Samples
Note that these are different from the ones I used for the above tests - these are mainly shorter:
LAME VBR Q0 MP3 (reference sound) Preview
LAME CBR 128kbps (JS) MP3 Preview
LAME VBR Q8 (JS) MP3 Preview
WMA9 CBR 64kbps Preview
WMA9 CBR 96kbps Preview
OGG Vorbis VBR Q1 Preview
Nero HE-AAC CBR 48kbps Preview
Nero HE-AAC v2 CBR 48kbps Preview
Nero HE-AAC CBR 24kbps Preview
Nero HE-AAC v2 CBR 24kbps Preview
Nero HE-AAC VBR 15% Preview
LAME CBR 128kbps (JS) MP3 Preview
LAME VBR Q8 (JS) MP3 Preview
WMA9 CBR 64kbps Preview
WMA9 CBR 96kbps Preview
OGG Vorbis VBR Q1 Preview
Nero HE-AAC CBR 48kbps Preview
Nero HE-AAC v2 CBR 48kbps Preview
Nero HE-AAC CBR 24kbps Preview
Nero HE-AAC v2 CBR 24kbps Preview
Nero HE-AAC VBR 15% Preview
Note for HE-AAC and HE-AAC v2 samples, make sure you're using a SBR/PS capable player, such as Winamp. Do not use players which do not decode SBR/PS such as iTunes/QuickTime.
Hope it's of some use :)