Hi all! I would like to use Ogg-Vorbis to encode a non audio waveform. My waveform is in .wav format, on 16 bit mono, with frequency range from 100Hz to 100MHz. It's about 100MB lenght. I need to compact it with lossy for net transfer. Is there something like this, already done, that can help me ?? How can I measure the distortion that Vorbis introduce? I'm sorry for my bad english. Thanks, Melvi
Vorbis is tuned for human audio. That means that the distortion it introduces will look completely nonsensical in terms of what data it discards, and what data it chooses to keep. Your brain "hears" audio differently than it exists in the form of a wave; there are certain things you don't hear, even though they are present. And, sometimes you "hear" what isn't even there, because of the way your brain interprets sound. The bottom line is that Vorbis discards data based on what your brain would also discard when listening to sound. This makes it very unsuitable for compressing anything that isn't going to be listened to by a human. If you must compress a waveform, do it losslessly. Any lossy waveform compression you will find will be optimized for humans, and that's not what you want. See... http://flac.sourceforge.net/ -Chris vincenzo cacciatore wrote:> Hi all! > I would like to use Ogg-Vorbis to encode a non audio waveform. My > waveform is in .wav format, on 16 bit mono, with frequency range from > 100Hz to 100MHz. It's about 100MB lenght. > I need to compact it with lossy for net transfer. > Is there something like this, already done, that can help me ?? > How can I measure the distortion that Vorbis introduce? > > I'm sorry for my bad english. > > Thanks, > > Melvi > _______________________________________________ > Vorbis mailing list > Vorbis@xiph.org > http://lists.xiph.org/mailman/listinfo/vorbis >
On 7/11/05, vincenzo cacciatore <vincenzo.cacciatore@gmail.com> wrote:> Hi all! > I would like to use Ogg-Vorbis to encode a non audio waveform. My > waveform is in .wav format, on 16 bit mono, with frequency range from > 100Hz to 100MHz. It's about 100MB lenght. > I need to compact it with lossy for net transfer. > Is there something like this, already done, that can help me ?? > How can I measure the distortion that Vorbis introduce?Given the frequency range of your data, vorbis is almost certainly completely useless to you. Vorbis is meant to compress audio data in such a way that the human ear can't hear the difference - the distortions that occur from this are extremely complex, and difficult to usefully characterise for non-audio purposes. One significant distortion you'd encounter is that the human ear can't hear anything above around about 20 kHz (depending on the ear...) - vorbis won't reproduce anything above a certain frequency (depending on the specific bitrate you use), so with a signal going up to 100 MHz, very little of your data will survive. I also don't think the reference encoder will accept such high frequencies. You could lie to it, but since vorbis is so inappropriate to this sort of task, it's unlikely to be worthwhile. Mike