1. Progress Report of Sphinx in Q4 2004 (Sep 1st to Dec 30th)
By Arthur Chan

2. High-light Release of Sphinx 3.5 Further Speed-up of Sphinx 3.5
Adaptation Progress
New tools:
decode_anytopo : the slow decoder
ep: high performance model –based end-pointer
cepview: versatile cepstral viewer
wave2feat: stand-alone tools for converting a wave file to its feature.

3. Release of Sphinx 3.5 Release Candidates Progress Features
Sphinx 3.5 RC II released at Oct 8, 2004
Sphinx 3.5 RC V released at Dec 19
Expected time official release: Beginning of January
Features
Stable live-mode APIs
MLLR
Further speed-up from Sphinx 3.4
Absolute CI GMM Selection
Approximate computation of CI senones
Complete Merging of s3.0 and s3.5 codebases.
Both slow and fast decoders are available in the same codebase.

4. Further technical detail of Sphinx 3.5
Portable across
OSes: Linux/Solaris/Mac OSX/Windows/BSD
Platforms: Alpha/x86/Solaris/PPC
Performance is tested extensively with vocabulary size varies from 10 to 10K
Test was carried out on Linux only
Results are repeatable in Windows/Linux.

5. Performance so far…… Live mode recognition results: TIDIGITS : 0.651%
WSJ 5K : 7.73%
Communicator : 13.0%

6. Further Speed-up of Sphinx 3.5
Absolute CI GMM Selection
Instead of using a beam, only compute a certain number of CD-senones
Results in 20% speed gain on top of 3.4 improvement without loss of accuracy
Speed-up of CI GMM computation
Using fast GMM computation technique on CI as well.
Better lower bound of speed.
Outlook
Implement tricks such as best GMM index and LDA. (ETA: February)

7. Adaptation Progress MLLR is proved to work in With 10-20% gain
RM1
WSJ (NAB)
With 10-20% gain
Experiment in unsupervised speaker adaptation is also performed in RM1 task.
For detail, please read David Huggins-Daines report.

8. New tools for Sphinx 3.5
Merging of Sphinx 3.0 and Sphinx 3.5 are completed.
S3.0 family:
Very accurate batch-mode decoder:
decode_anytopo:
5% better than non-optimized fast decoder
Very slow 4xRT to 10xRT. Useful for batch model processing like in CALO scenario.
Auxillary:
align: aligner
allphone: phoneme recognition
dag: best-path finder in a lattice
astar: n-best generator

9. New tools for Sphinx 3.5 (cont.)
Other tools:
(New!) ep: Speed-up end-pointer of Ziad’s implementation
For detail of ep, please read Ziad’s report.
cepview: cepstral viewer
Originally a standalone tool, now distributed with s3.5
wave2feat: stand-alone feature extraction routine.
Exactly the same as the one in the live-mode decoder.

10. Outlook in Q1 2004 Official Release of s3.5 (ETA January)
Further Improvement in Speed (ETA February)
Refactoring of Sphinx3.X and SphinxTrain (ETA March)
It is time to turn our focus to accuracy.