7 ms·

Novocaine: painless high-performance audio on iOS and OS X

109 points by alexbw 14y ago

guscost 14y ago
I just finished making my own version of this! What unfortunate timing, but kudos to you.
- melloclello 14y ago
  Is it open source? I'd love to check it out.
  - guscost 14y ago
    I'm thinking of abstracting out some of the quirks and open-sourcing the audio engine at some point, but it isn't nearly as intuitive or compatible as this library as it was developed recently along with the application that uses it... On top of that, no vector operations or ring buffers are currently implemented, so I wouldn't be surprised if this library has significantly better performance. I do have a bit of a wish list of features to add to my code after taking a look at some of the techniques used here. It's complicated work, but I've never had a better experience learning a complicated system. My implementation basically added a playback and mixing interface to the audio engine from this sample mixer project: http://developer.apple.com/library/ios/#samplecode/MixerHost/Introduction/Intro.html http://developer.apple.com/library/ios/#samplecode/MixerHost...
    - andyzweb 14y ago
      By vector operations do you mean using something like the Accelerate framework? or SSE/NEON primitives? or just retooling your code so that your compiler can make attempts to vectorize when possible?
      - guscost 14y ago
        I'm a bit new to this stuff, so I'm not exactly sure to be honest! It looks like he is piping several array operations through Accelerate, and I suspect there is at least one part of my render callback function that would finish faster with appropriate vectorization. If anyone has any relevant tips about how the Obj-C LLVM or whatever it is actually works and what it means for low-latency audio, please do share. My current strategy is ruthless and minimal static allocation but I don't know what is best.
deleted 14y ago
[deleted]
kscottz 14y ago
This looks great. Most audio and image processing libraries are a pain and I always end up wrapping them in something like this. It is nice to see someone open source a well written wrapper.
melloclello 14y ago
Oh my god. I just spent the last month on and off trying to wrap my head around CoreAudio. I'm flabbergasted, thank you so much.
- melloclello 14y ago
  Update: worksforme on Mac and iOS, going to start playing with this tonight
ianloic 14y ago
Is this open source? The source files say All Rights Reserved.
- alexbw 14y ago
  Fixed.
bludwype 14y ago
just bought all your apps. any other useful and/or interesting and/or fun audio analysis apps out there anyone can recommend??
- guscost 14y ago
  Stay tuned...
- kennywinker 14y ago
  http://itunes.apple.com/ca/artist/audioforge-labs-inc./id305996692 http://itunes.apple.com/ca/artist/audioforge-labs-inc./id305... Made by a developer I met at WWDC. Good stuff and he puts a whole lot of love into them.
SpiderX 14y ago
Absolutely hate the name.
- bigiain 14y ago
  I guess I'm showing my age here, but I've now got the song Novocaine by The Eels running around my head: http://www.youtube.com/watch?v=V2yy141q8HQ http://www.youtube.com/watch?v=V2yy141q8HQ That seems like a pretty good "hook" to hang your audio library off (I guess targeting your audio library marketing to people who were listening to pop music in 1996 is a questionable tactic though…)
- BrandonBT 14y ago
  Why do you hate it?
  - SpiderX 14y ago
    Because it gives you absolutely no idea what the product actually does, and it's un-googleable. Try googling novocaine - guess what, you won't find this in the first page of results. Good luck with it. I'm sure it may be one awesome piece of software, but the name is just dumb.
    - elithrar 14y ago
      > Try googling novocaine - guess what, you won't find this in the first page of results. Good luck with it. I'm sure it may be one awesome piece of software, but the name is just dumb. A lot of web projects are "un-googleable", especially when they are first kicking off. Django would be a good example of this—searching for "Django" would often return results about Django Reinhardt, a jazz musician, instead of the web framework. I think it's a fair assumption to say that an interested programmer might think to append github[1] or audio[2] to their search, in which case the result is in the top 3. [1] https://duckduckgo.com/?q=novocaine+github https://duckduckgo.com/?q=novocaine+github [2] https://duckduckgo.com/?q=novocaine+audio https://duckduckgo.com/?q=novocaine+audio
      - 14y ago
radarsat1 14y ago
Ah, interesting, reminds me of RtAudio. (Similar thing for C++, though this seems to require even less boilerplate.. on the other hand RtAudio is cross-platform.)
alexbw 14y ago
Hey everybody, Novocaine is my baby, and it's completely awesome to see folks already using it. For the record, it's open-source, I just forgot to stick the MIT license at the top. Or would folks prefer BSD? Let me know, I'm flexible. The only thing I care about is that people use it to make awesome software. If anybody's a Boston local, I'll be talking about iOS audio (both novocaine and some fancier frequency analysis, I hope) at the Berklee College of Music CS club tomorrow, 6-8pm, at 150 Mass Ave, room 118. And, if you dig novocaine, check out the apps I made with it: http://itunes.apple.com/us/artist/alex-wiltschko/id344345862 http://itunes.apple.com/us/artist/alex-wiltschko/id344345862
- cwb71 14y ago
  Alright fine, you just sold me a copy of Octave! Thanks for releasing this.
- podperson 14y ago
  Your timing couldn't be better. I was literally in the process of trying to figure out how the heck the SpeakHere demo actually works -- now maybe I don't have to. It would be nice to have a little more documentation. How do you set audio sample formats? (I assume you can.)
  - alexbw 14y ago
    Documentation will be forthcoming. What do you mean by audio sample formats? One of the things I tried to do was make sure that you never, ever, EVER have to think about anything but floating point audio. In my experience, audio comes in as either float or SInt16s (I've never seen fixed-point coming in by default, but I haven't done an enormous amount of odd-peripheral Mac audio), and novocaine just handles it for you.
    - Tloewald 14y ago
      I'm working on a VoIP app and the back end requires specific audio formats.
vecter 14y ago
Whoa this look great! I haven't had a chance to dig through, but is it possible to capture the audio that's being played? I'm thinking of recording gameplay audio. Thanks!
deleted 14y ago
[deleted]
hackermom 14y ago
Correct me if I'm wrong, but isn't Novocaine still an abstraction layer that interfaces with Core Audio (I haven't had a moment to look at the sources yet)? I understand that it's simpler to deal with, but how is it more "high-performant" than working with Core Audio directly?
- kennywinker 14y ago
  I think he means "painless" in comparison with working directly with audio units, and "high-performance" in comparison with the higher-level abstractions provided by Apple. Having tried my hand at core audio code a few times, this is an amazingly simple API. I've got some app ideas I'd like to use this in.
psych 14y ago
Is it possible with Novocaine to mix for example in app audio and mic recording into one sound file? Cheers

109 points by alexbw 14y ago

guscost 14y ago

I just finished making my own version of this! What unfortunate timing, but kudos to you.

melloclello 14y ago
Is it open source? I'd love to check it out.
- guscost 14y ago
  I'm thinking of abstracting out some of the quirks and open-sourcing the audio engine at some point, but it isn't nearly as intuitive or compatible as this library as it was developed recently along with the application that uses it... On top of that, no vector operations or ring buffers are currently implemented, so I wouldn't be surprised if this library has significantly better performance. I do have a bit of a wish list of features to add to my code after taking a look at some of the techniques used here. It's complicated work, but I've never had a better experience learning a complicated system. My implementation basically added a playback and mixing interface to the audio engine from this sample mixer project: http://developer.apple.com/library/ios/#samplecode/MixerHost/Introduction/Intro.html http://developer.apple.com/library/ios/#samplecode/MixerHost...
  - andyzweb 14y ago
    By vector operations do you mean using something like the Accelerate framework? or SSE/NEON primitives? or just retooling your code so that your compiler can make attempts to vectorize when possible?
    - guscost 14y ago
      I'm a bit new to this stuff, so I'm not exactly sure to be honest! It looks like he is piping several array operations through Accelerate, and I suspect there is at least one part of my render callback function that would finish faster with appropriate vectorization. If anyone has any relevant tips about how the Obj-C LLVM or whatever it is actually works and what it means for low-latency audio, please do share. My current strategy is ruthless and minimal static allocation but I don't know what is best.

deleted 14y ago

[deleted]

kscottz 14y ago

This looks great. Most audio and image processing libraries are a pain and I always end up wrapping them in something like this. It is nice to see someone open source a well written wrapper.

melloclello 14y ago

Oh my god. I just spent the last month on and off trying to wrap my head around CoreAudio. I'm flabbergasted, thank you so much.

melloclello 14y ago
Update: worksforme on Mac and iOS, going to start playing with this tonight

ianloic 14y ago

alexbw 14y ago
Fixed.

bludwype 14y ago

just bought all your apps. any other useful and/or interesting and/or fun audio analysis apps out there anyone can recommend??

guscost 14y ago
Stay tuned...
kennywinker 14y ago
http://itunes.apple.com/ca/artist/audioforge-labs-inc./id305996692 http://itunes.apple.com/ca/artist/audioforge-labs-inc./id305... Made by a developer I met at WWDC. Good stuff and he puts a whole lot of love into them.

SpiderX 14y ago

Absolutely hate the name.

bigiain 14y ago
I guess I'm showing my age here, but I've now got the song Novocaine by The Eels running around my head: http://www.youtube.com/watch?v=V2yy141q8HQ http://www.youtube.com/watch?v=V2yy141q8HQ That seems like a pretty good "hook" to hang your audio library off (I guess targeting your audio library marketing to people who were listening to pop music in 1996 is a questionable tactic though…)
BrandonBT 14y ago
Why do you hate it?
- SpiderX 14y ago
  Because it gives you absolutely no idea what the product actually does, and it's un-googleable. Try googling novocaine - guess what, you won't find this in the first page of results. Good luck with it. I'm sure it may be one awesome piece of software, but the name is just dumb.
  - elithrar 14y ago
    > Try googling novocaine - guess what, you won't find this in the first page of results. Good luck with it. I'm sure it may be one awesome piece of software, but the name is just dumb. A lot of web projects are "un-googleable", especially when they are first kicking off. Django would be a good example of this—searching for "Django" would often return results about Django Reinhardt, a jazz musician, instead of the web framework. I think it's a fair assumption to say that an interested programmer might think to append github[1] or audio[2] to their search, in which case the result is in the top 3. [1] https://duckduckgo.com/?q=novocaine+github https://duckduckgo.com/?q=novocaine+github [2] https://duckduckgo.com/?q=novocaine+audio https://duckduckgo.com/?q=novocaine+audio
    - 14y ago

radarsat1 14y ago

Ah, interesting, reminds me of RtAudio. (Similar thing for C++, though this seems to require even less boilerplate.. on the other hand RtAudio is cross-platform.)

alexbw 14y ago

Hey everybody, Novocaine is my baby, and it's completely awesome to see folks already using it. For the record, it's open-source, I just forgot to stick the MIT license at the top. Or would folks prefer BSD? Let me know, I'm flexible. The only thing I care about is that people use it to make awesome software. If anybody's a Boston local, I'll be talking about iOS audio (both novocaine and some fancier frequency analysis, I hope) at the Berklee College of Music CS club tomorrow, 6-8pm, at 150 Mass Ave, room 118. And, if you dig novocaine, check out the apps I made with it: http://itunes.apple.com/us/artist/alex-wiltschko/id344345862 http://itunes.apple.com/us/artist/alex-wiltschko/id344345862

cwb71 14y ago
Alright fine, you just sold me a copy of Octave! Thanks for releasing this.
podperson 14y ago
Your timing couldn't be better. I was literally in the process of trying to figure out how the heck the SpeakHere demo actually works -- now maybe I don't have to. It would be nice to have a little more documentation. How do you set audio sample formats? (I assume you can.)
- alexbw 14y ago
  Documentation will be forthcoming. What do you mean by audio sample formats? One of the things I tried to do was make sure that you never, ever, EVER have to think about anything but floating point audio. In my experience, audio comes in as either float or SInt16s (I've never seen fixed-point coming in by default, but I haven't done an enormous amount of odd-peripheral Mac audio), and novocaine just handles it for you.
  - Tloewald 14y ago
    I'm working on a VoIP app and the back end requires specific audio formats.

vecter 14y ago

Whoa this look great! I haven't had a chance to dig through, but is it possible to capture the audio that's being played? I'm thinking of recording gameplay audio. Thanks!

deleted 14y ago

[deleted]

hackermom 14y ago

Correct me if I'm wrong, but isn't Novocaine still an abstraction layer that interfaces with Core Audio (I haven't had a moment to look at the sources yet)? I understand that it's simpler to deal with, but how is it more "high-performant" than working with Core Audio directly?

kennywinker 14y ago
I think he means "painless" in comparison with working directly with audio units, and "high-performance" in comparison with the higher-level abstractions provided by Apple. Having tried my hand at core audio code a few times, this is an amazingly simple API. I've got some app ideas I'd like to use this in.

psych 14y ago

Is it possible with Novocaine to mix for example in app audio and mic recording into one sound file? Cheers