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Embedded Audio Coder (EAC) - Mono Audio

We compare the EAC against the following benchmark audio coders.

The original audio waveform can be found here (29.3MB).

You must download the corresponding decoder before you can listen to the clip. The test clip is pretty long (almost 6 minutes), and consists of different audio content. For best comparison, you may want to first download the clip to the local, decoded it to an editable form(e.g., wav), and listen to the clips in your favoriate player.

All benchmark coders compress the audio waveform directly into the target bitstream. However, for the EAC, only one encoding operation is performed to convert the original audio waveform into a master compressed bitstream and a companion file. The rest of the bitstream is parsed from the master bitstream through the EAC parser. Here is the EAC master bitstream and companion file.

The comparison can be shown with the following table. Within each cell, the noise-mask-ratio (NMR) of the decoded clip is shown. The smaller the NMR value, the better the coding quality. You may access the actual clip by clicking on the link.

Coder	64kbps	48kbps	32kbps	24kbps	16kbps	8kbps	4kbps
EAC	-3.79	-1.59	1.43	3.29	5.20	6.86	7.24
MP3	8.04	9.17	12.75	12.83	15.25	14.72	N/A
MPEG-4	3.33	4.59	5.75	6.44	6.86	7.54	N/A
WINSAC	6.63	6.99	7.47	7.73	8.19	N/A	N/A
Real	3.10	3.89	4.70	5.81	N/A	N/A	N/A
WMA	N/A	0.25	2.94	N/A	5.94	8.87	N/A

Listen to the audio clips yourself. Your comments are welcome. Please contact the author at jinl@microsoft.com should you have any comments or suggestions.