Ask HN: Guitar tabs online
We do want to change the way people get guitar tabs (chords). You submit mp3 and get guitar tabs back for it. Tabs will be synchronized to your song and could be inserted to any page as flash object.
You can get one file for free in 24 hours. Processing is FIFO based, so expect your chords to be ready in couple of hours, depending on the load, unless you will pay for speedup processing :)
Small history. We had introduced Chords! Winamp quite a while ago, and general comment was additional players/OS, so we decided to go purely web, without any software installation.
Try it http://chords.fm/online/web
Any comments are be welcome.
23 comments
[ 5.1 ms ] story [ 73.1 ms ] threadHow accurate is it ?
Possible other output channel (if you got this far) would be automated mp3 to midi transcription.
You must have had some spectacular headaches to deal with, especially with multiple instruments playing through one-another.
Tangent: Given your expertise, do you think it would be theoretically possible to write a program that attempts to detects the '1' beat in Latin/Afro-Cuban music, using your techniques, live, in real-time? Maybe using clave detection. Thanks in advance.
There is some literature out there on real-time beat following but the precision is poor so far
I'd love it if you added bass tabs. I don't expect the market is large enough to justify it, but I thought I'd ask.
You could e-mail me at kos@cbmsnetworks.com if HTTP problem will persist.
If you will have this problem constantly just e-mail me at kos@cbmsnetworks.com
We can't find page you have requested.
1) Recognizing the musical notes. From here (http://www.owlnet.rice.edu/~elec301/Projects02/realTime/301P...): "Fourier analysis allows us to decompose any such pressure function into a sum of sinusoids. Therefore, any sound can be represented as a sum of sinusoids. If the sound has a pressure function that is aperiodic with respect to time, decomposition into sinusoids is quite complicated. However, if the sound is periodic with respect to time, it can be easily decomposed and transferred to the frequency domain using a computer and the Fast Fourier Transform." And since each note has a unique frequency/octave associated with it, it could be easily identified via a frequency to note database.
2) Recognizing the time-measure of the song (i.e., whether the song is 4/4 or 3/5), since this is required to do straight-forward Fourier transform and also perhaps to mark chord changes. I'm guessing this is either done by simple analysis of any periodic and consistent rises in the sound frequency of the song. Or perhaps, this is done via the same Fourier transform analysis of the sound waves and mapping out where the peaks fall.
3) Recognizing the chords; once you have figured out the notes and beat measure. The rest follows pretty easily, you have a chord database of all of the note-triads to chords and map out the chords accordingly. But the challenge there is, what if you have a rhythm guitar going at the same time while there's a solo? How do you map which notes to which guitar. Perhaps, the instruments are recorded onto different channels and you group on notes according on the degree to which they pan to the left, to the right, etc.
4) Separating out the instruments from one another; Maybe grouping notes via panning is not enough. Perhaps, you need to do some timbre analysis to group the notes that sound like a guitar vs. notes that sound like a bass guitar. Since each instrument has a distinct harmonics and overtone. You guys have some type of classification algorithm that classifies what portion of the sound belongs to what timbre of the instrument.
Any comments/response is appreciated.
There's some further information as to how it's achieved in the comments, as well as link to the academic paper the product is based on.