ITU-T G.719: A New Low-Complexity Full-Band (20KHZ ... - Polycom

2009 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics October 18-21, 2009, New Paltz, NY
was that the G.719 candidate codec at 32, 48, and 64kbps be
proven “Not Worse Than” the reference codec at 40, 56, and 64
kbps, respectively, with a 95% statistical confidence level. In
addition, the G.719 candidate codec at 64 kbps was also tested
against the G.722.1C codecs at 48 kbps for Experiment 2.
The subjective test results for the G.719 codec are shown in
Figures 3-6. Statistical analysis of the results showed that the
G.719 codec met all performance requirements specified for the
subjective Optimization/Characterization test. For experiment 1
the G.719 codec was better than the reference codec at all bit
rates in both languages. For experiment 2 the G.719 codec is
better than the reference codec at the lowest bit rate for all the
items and at the two other bitrates for most of the items.
An additional subjective listening test for the G.719 codec
was conducted later to evaluate the quality of the codec at rates
higher than those described in the ITU-T test plan. Because the
quality expectation of the codec at these high rates is high, a
pre-selection of critical items, for which the quality at the lower
bitrate range was most degraded, was conducted prior to testing.
The test results are shown in Figure 7. It has been proven that
transparency was reached for critical material at 128 kbps.
DMOS
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Ref 40kbps
G.719 32kbps
Ref 56kbps
G.719 48kbps
Ref 64kbps
Speech (North American English)
G.719 64kbps
Ref 40kbps
G.719 32kbps
Ref 56kbps
G.719 48kbps
Ref 64kbps
Clean Reverberant Reverberant and Noisy
Figure 3: Subjective test results – Experiment 1 (English).
DMOS
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Ref 40kbps
G.719 32kbps
Ref 56kbps
G.719 48kbps
Ref 64kbps
G.719 64kbps
Speech (French)
Ref 40kbps
G.719 32kbps
Ref 56kbps
G.719 48kbps
Ref 64kbps
Clean Reverberant Reverberant and Noisy
Figure 4: Subjective test results – Experiment 1 (French).
DMOS
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Ref
40kbps
G.719 64kbps
G.719 64kbps
Ref 40kbps
Ref 40kbps
Mixed-content and Music (North American English)
G.719
32kbps
Ref
56kbps
G.719
48kbps
Ref
64kbps
G.719
64kbps
G.719 32kbps
G.719 32kbps
Ref 56kbps
Ref 56kbps
G.719 48kbps
G.719 48kbps
G.722.1C
48kbps
Ref 64kbps
Ref 64kbps
G.719 64kbps
G.719 64kbps
G.719
64kbps
Figure 5: Subjective test results – Experiment 2 (English).
268
DMOS
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Ref
40kbps
G.719
32kbps
Mixed-content and Music (Spanish)
Ref
56kbps
G.719
48kbps
Ref
64kbps
G.719
64kbps
G.722.1C
48kbps
G.719
64kbps
Figure 6: Subjective test results – Experiment 2 (Spanish).
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
Source
G.719
32kbps
Source
Additional Subjective Test Results (DMOS)
G.719
48kbps
Source
G.719
64kbps
Source
G.719
80kbps
Source
G.719
96kbps
Source
G.719
112kbps
Figure 7: Additional subjective test results.
7. CONCLUSION
This paper has presented the 20 kHz full-band audio coding
algorithm and subjective Optimization/Characterization test
results of ITU-T Recommendation G.719. The G.719 codec
features very high audio quality, extremely low computational
complexity, and low algorithmic delay compared to other stateof-the-art
audio coding codecs. Subjective test results show that
the G.719 codec achieves transparent audio quality at 128 kbps.
The main intended applications for this codec are
videoconferencing and teleconferencing, as well as Internet
streaming.
8. REFERENCES
[1] ITU-T Recommendation G.719, “Low-complexity fullband
audio coding for high-quality conversational
applications,” June 2008.
[2] H. S. Malvar, Signal Processing with Lapped Transforms.
Norwood, MA: Artech House, 1992.
[3] M. Xie, “Lattice Vector Quantization and its Applications
in Speech and Audio Coding,” in Speech Processing in
Modern Communication: Challenges and Perspectives.
Springer, To appear.
[4] J. H. Conway and N. J. A. Sloane, Sphere Packings,
Lattices and Groups. Springer-Verlag, New York, 1988.
[5] C. Lamblin and J.-P. Adoul, “Algorithme de quantification
vectorielle sphérique à partir du réseau de Gosset d’ordre
8,” Annales des Télécommunications, pp. 172-186, 1988.
[6] ITU-T Recommendation G.191, “Software tools for speech
and audio coding standardization,” Sept. 2005.
[7] http://sourceforge.net/project/showfiles.php?group_id=290
&package_id=309.
Source
G.719
128kbps