[PD] [OT] soundfile compression
fbar at footils.org
Mon Mar 22 10:11:12 CET 2004
john saylor hat gesagt: // john saylor wrote:
> let's say i have a .wav file, and i want to make it smaller. this is the
> list of options i am aware of:
> 1. i can reduce the channels to 1 [mono]
> 2. i can reduce the sample rate from 44100 Hz.
> 3. i can reduce the bits per sample
> in terms of minimizing fidelity loss, i would guess that the list would
> go like this [with the least loss leading]:
> 1. channels
> 2. rate
> 3. bits
> is this correct?
It depends. All three do very different things: 1 affects
spatialization, 2 affects highest possible frequency, and 3 mostly
affects dynamic range and signal/noise ratio.
So selection of a compression method depends on what you would miss
most. The popular compression algorithms like mp3 or ogg automate this
selection somehow. For example, they join stereo channels in those
places, where there is not much difference between both channels, and
they reduce bitrate dynamically according to the amount of information
in a signal.
> and what tools would i use to perform these manipulations? sox for all?
Any soundfile editor will do this. Sox is great for batched
processing, but also take a look at editors like Snd, Rezound or
Frank Barknecht _ ______footils.org__
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