That won't be a problem if you measure the correlation locally, but how exactly? Certainly anything outside the cross-fade region should be excluded from the measurement. And inside it matters most wherever the mixing ratio is close to 50-50, as in that cases phase difference of the two signals gives the greatest contribution to the resulting measurable volume envelope of the mixed signal. Probably the data should be windowed for measurement of correlation (and volume), depending on the mixing function...
-olli On Fri, Jul 15, 2011 at 2:24 PM, Wen Xue <xue....@eecs.qmul.ac.uk> wrote: > I have the following made-up scenarios - > 1) If I twist the 2nd half of some x(t) by 180 degrees then it becomes > orthogonal to the original x(t). How do we cross-fade it with x(t)? > 2) If I twist the 1st third of x(t) by 180 degrees and 3rd third by 90 > degrees? > 3) If I twist 2nd and 4th and quarters of x(t) by 180 degrees? > In all such cases the correlation is 0. Do we cross-fade them in the same > way? > > Xue > > > > -----Original Message----- > My objective has not been to find a method for automatic splicing, but > to do nice cross-fades at given splice points. > > There were multiple objectives: > * Intuitive definition of the cross-fade shape. Mixing ratio as a > function of time is a good definition. > * For stationary signals, there should be no clicks or transients > produced. This is taken care of by the smoothness of the cross-fade > envelopes. > * For stationary signals, the resulting measurable transition from the > volume level of signal 1 to volume level of signal 2 should follow the > chosen cross-fade shape. This can be accomplished knowing the volume > levels of the two signals and the correlation coefficient between the > two signals. > > -olli > > -- > dupswapdrop -- the music-dsp mailing list and website: > subscription info, FAQ, source code archive, list archive, book reviews, dsp > links > http://music.columbia.edu/cmc/music-dsp > http://music.columbia.edu/mailman/listinfo/music-dsp > -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp
