Date: Sat, 31 Jan 1998 18:12:25 -0500 (EST) From: Jim Durham <durham@w2xo.pgh.pa.us> To: freebsd-multimedia@FreeBSD.ORG Subject: General notes about sound recording on FreeBSD 3.0. Message-ID: <XFMail.980131181225.durham@w2xo.pgh.pa.us>
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Since there was a recent thread on doing sound recording on FreeBSD, I thought I'd report on what I've been doing here and results thereof. I have been doing quite a bit of recording using my SB16 on a 5X86-133 running 3.0-SNAP-971225. Low quality recordings at 11025 khz scan rates and below work as well as can be expected. However, at 44100 khz scan rate, small "ticks" appear in when the sound level is fairly loud. These are almost undetectable, but, once you notice them, they're really annoying. Sort of like someone ticking the edge of a piece of paper in the background of the recording. A test I made with silence followed by a loud sound produced a "tick" right *before* the sound. I don't know what this might mean. I'm using a simple program that reads and writes bits to /dev/dsp. The problem happens either on the mic or line input to the card. I've tried other applications, like mxv, and dsp-record(play), but mxv will not change scan rates and dsp-record(play) does not work for me at all. This is while using a kernel with the Voxware driver. I decided to try Luigi's driver to see if results were similar, but can't get it to work on 3.0-SNAP-971225. (Locks up entire system after delivering short burst of sound). I was hoping that perhaps this might be a cure. 8-(. I can't report an error message, because the system locks immediately and must be hard-rebooted. This is not at all typical of this hardware to lock up. Finally, the RealAudio 3.0 encoder will core-dump immediately when you try to use the line or mic input to record a RealAudio file to disk. If you first make a raw audio file, then encode that, it works fine. I've mentioned this before and reported it to RealAudio. Any comments? Jim Durham
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