Re: VariSpeed and Timestamps
Re: VariSpeed and Timestamps
- Subject: Re: VariSpeed and Timestamps
- From: Ethan Funk <email@hidden>
- Date: Wed, 24 Nov 2004 10:59:08 -0700
The file playing part of my code is based on Kurt Revis'
PlayBufferSoundFile, which I have mostly rewriten (except for his
buffer code) in C++ and adapted for my needs. It does use QT for
decompression. The FilePlayer portion of my code works fine except for
a memory leak I have not tracked down yet. The FilePlayer uses a
AudioConverter AU to sample rate convert from the files native rate to
96,000 ksps before being dumped into a MaxtrixMixer AU. I am using a
VariSpeed converter for my InputPlayer, which currently doesn't work
for reasons unknown, so I may not be the best source of help of the
VariSpeed AU.
I have posted the whole project at
http://studio475.com/audiorack/arplayer1.1.zip for you to take a look
at. This is a work in progress, but I hope at least the FilePlayer
portion of the code can be some help to you.
The project builds a command line program called arplayer, that listens
on tcp port 9550 for connection. Telneting into this port lets you
control the eight player so you can load them with files, set segue
times, start, stop, fade, etc. The input player doesn't work, and
currently, the default output device is used unless you specify another
device number when you run arplayer. "help" will return a list of
commands from a telnet session. Player numbers are 0 through 7. File
paths allow spaces and do not except "\" notation.
Any one care to help we with the InputPlayer? This is an open source
project.
Ethan...
On Nov 23, 2004, at 23:34, Felipe Baytelman wrote:
Hi Ethan:
I suspect you are using the QTSoundFilePlayer project, because of
your ring buffer. Any way, if not, I'm very interested in your project
advance so far. I'm really newbie to AudioUnits, and I'm using the
mentioned project to decode music files. Currently, I've couldn't find
out how to connect that decoding system to any AudioUnit -VariSpeed,
specially.
Can you help me with this? Maybe sharing part of the code that does
the connection between the playback and the varispeed? Are you reading
files? Through QuickTime decoding?
Anyway, thank you.
Felipe Baytelman.
On Nov 17, 2004, at 10:47 PM, Ethan Funk wrote:
If I call AudioUnitRender to get a sample buffer from a VariSpeed
audio unit, passing it my local sample time stamp, what time stamp
will the VariSpeed AU pass along to it's render call back when it
pull on the next unit in the chain (a ring buffer in my case)? Will
it just pass along my time stamp? Does it used my time stamp
multiplied/divided by the rate convertion scalar? Does it have it's
own internal input sample counter that it uses?
I am having trouble where the resuling audio sounds modulated by a
square wave at around the render period rate which makes me suspect
the the time stamps are skipping through ring buffer when the
VariSpeed filter pulls on it.
Thanks,
Ethan....
--
Felipe Baytelman
email@hidden
080 5498 9347
email@hidden
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