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Beat Critic: Beat Tracking Octave Error Identification By Metrical Profile Analysis

Leigh M. Smith

Computational models of beat tracking of musical audio have been well explored, however, such systems often make "octave errors", identifying the beat period at double or half the beat rate than that actually recorded in the music. A method is described to detect if octave errors have occurred in beat tracking. Following an initial beat tracking estimation, a feature vector of metrical profile separated by spectral subbands is computed. A measure of subbeat quaver (1/8th note) alternation is used to compare half time and double time measures against the initial beat track estimation and indicate a likely octave error. This error estimate can then be used to re-estimate the beat rate. The performance of the approach is evaluated against the RWC database, showing successful identification of octave errors for an existing beat tracker. Using the octave error detector together with the existing beat tracking model improved beat tracking by reducing octave errors to 43% of the previous error rate.

Rhythmic Similarity Using Metrical Profile Matching

ICMC 2010
Leigh M. Smith

A method for computing the similarity of metrical rhythmic patterns is described as applied to the audio signal of recorded music. For each rhythm, a combined feature vector of metrical profile and syncopation, separated by spectral subbands, hypermetrical profile, and tempo are compared. The descriptive capability of this feature vector is evaluated by it's use in a machine learning rhythm classification task, identifying ballroom dance styles using a support vector machine algorithm. Results indicate that with the full feature vector a result of 67% is achieved. This improves on previous results using rhythmic patterns alone, but does not exceed the best reported results. By evaluating individual features, measures of metrical, syncopation and hypermetrical profile are found to play a greater role than tempo in aiding discrimination.

Obamas score card

In case anyone in the Democratic party is wondering why support disappeared in Massachusetts, perhaps examining the score card of the Obama administration will reveal why some people feel the behaviour of the executive is little different from the war criminal he replaced.

  • Gave money to the banking executives and left the majority of victims of their predatory lending with no support. He should have just nationalised any bank going bust, sacked the executive boards, and established a means to renegotiate usury mortgages.
  • Attacked a country (Pakistan) which had not attacked the U.S. in the first week of taking office. Even Bush took 9 months before he acted like Hitler.

Donating for Haiti

To help the people of Haiti, I recommend donating to Partners in Health that already have offices in Haiti and a long history of provision of aid, without preconditions and excessive bureaucracy. I have donated to them during the flooding that occurred in 2004 and they do great work. They have already provided two trucks of medical equipment into Port-au-Prince from their office in another town.

Of course, if you choose another aid organisation, that's still great.

Climate displacement is happening now

Via Jill, I learned of a documentary that is currently seeking funding, following the people of Carteret Island in the Pacific who are being displaced by rising waters. There are other climate refugees, such as people fleeing the conflict in Darfur, due ultimately to the evaporation of Lake Chad and loss of arable lands. However, the issue of impending loss of low lying islands due to erosion from sea level rise has been raised by many island nations such as Tuvalu and the Maldives. The film illustrates the effect on the people of Carteret island of forced emigration to nearby Bougainville island as the first refugees solely due to climate change. The film is seeking funding online, which is in the form of pledges.

Minuet in E major duet

A Minuet in E major recorded as a double tracked duet by the Baroque composer Adam Falckenhagen.


My letter to the PM: Please pay our climate debt at Copenhagen

Dear Prime Minister,

I urge you to recognise Australia's obligations to the world in it's negotiations at the Copenhagen COP-15 summit. Australia heavily burdens the world with it's continued reliance on coal and natural gas export industries. This is a short-sighted economy which is extremely exposed to changes in production, demand and political influence from multinational corporations. While successive Australian governments have provided enormous taxpayer subsidies to these carbon intensive industries, we have invested relatively tiny amounts of money in renewable energy industries. This is holding back Australian research and development in knowledge intensive renewable technologies.

MusicKit V5.6.2 now available

There is now a new release available of the MusicKit that will run on MacOS 10.4 through to 10.6 and GNUstep. Binaries for MacOS 10.6 Intel only are now also available. Versions of MacOS below 10.4 are no longer officially supported. Please refer to MusicKit_ChangeLog.txt for the official list of changes, but the highlights are:

  • MacOS 10.6 is now supported.

  • Vector hardware on MacOS X is supported for both PPC and Intel.

  • Apple AudioUnits are now built as standard in the SndKit.

My Letter to W.A. Newspapers: Expat climate disbelief

As an expat Aussie living in France and watching the climate debate in Canberra, it is with a sense of shame and disbelief to watch the Labour and Liberal parties obscure the real issues of climate change. Prime minister Rudd's concessions to the Liberal party climate deniers is simply enormous corporate welfare of $5.8 billion to be paid by taxpayers to keep the coal industry polluting. An emissions trading scheme is just permission to pollute by industries who's era is over. Europe has already demonstrated how ineffective an ETS is at reducing carbon, while leading to spiking electricity costs. Australia needs a flat carbon fee that is not able to be manipulated, to properly reflect the cost the country and our children will continue to pay into the future.

Sax Oud Duo

I had the wonderful opportunity to jam with Martha Sparks, an excellent alto saxophonist from Melbourne at my apartment in NYC, early 2001. This is an improvisation between Martha and me on sax and oud (Arabic lute) respectively.

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