Am Mittwoch, 2. Juli 2008 schrieb Kjetil S. Matheussen: > Arnold Krille: > > Am Mittwoch, 2. Juli 2008 schrieb Kjetil S. Matheussen: > > > I think that is complete overkill. I just tried recorded 128 channels > > > of 32bit/44100hz at once, without problem. And my machine is 5 years > > > old 2Gz barebone, using only a single PATA ide disk. > > > This was using jack_capture, and only recording silence (ie. > > > non-connected jack ports). Maybe the silence makes a difference.(?) > > > > For jack and ardour/timemachine/jack_capture it is completely irrelevant > > if the double-numbers contain 0.0, 1E-<incredibly high> or some > > (pseudo-)random > > values between -1 and 1. Its still sizeof(double) that is saved to disk > > for each channel and sample... > > > > It only makes a difference when using compressed formats like mp3, flac, > > etc. But ardour doesn't support this (yet). > > You can't just bombastically spew out things like that without > backing it up with some sort of facts or at least arguments. > Since the buffers isn't written to by anything other than zeros, > there could theoretically be a smaller chance of cache misses. Whether it > makes a difference is a different story. As the transfer from memory to hd is _the_ slow point of the setup, cache-misses or hits don't influence that at all. And when you are not calculating anything (apart from 64bit to 32bit double-to-float), you don't access the cache. DMA is the keyword. Still it doesn't make saving to disk faster than your disks and controllers speed. And I am pretty sure that there is _no_ compression involved in that part, otherwise this would seriously affect data-integrity if the controller did an unwanted compression. Is that enough back-up for my "bombastically spilled out" argumentation? A double (or float) to transfer to disk is still a double (float) to transfer to disk regardless wether the value is 0, close to zero or something close to INFINITY... Arnold -- visit http://www.arnoldarts.de/ --- Hi, I am a .signature virus. Please copy me into your ~/.signature and send me to all your contacts. After a month or so log in as root and do a "rm -rf /". Or ask your administrator to do so...
Attachment:
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
