Am Dienstag, den 05.02.2008, 22:47 +0100 schrieb Raffaella Traniello: > I'd add: > * Audio fade (and meters?) set to -40.0 to 6.0
Hello all, oh yes, this reminds me of some unfinished work. Indeed Audio faders and meter need to be -96dB to +6dB, because that's the dynamic range of 16bit PCM. (24bit has even -124dB) Pierre Dumuid discovered this misconception quite a while ago. Now this brings us to a quite complicated issue, the usage of dynamic range. While for much "everyday work" you won't use more then -20dB (and even apply a compresor to the sound to squeeze it into this limited range, so it sounds "good" on your car radio), for quality oriented work you certainly use all the dynamic range. Now, (as Pierre pointed out correctly at that time), if we just change the effective "default dynamic range" of cinelerra, this will change the meaning of the audio fade curves in quite a dramatic manner and -- whats most important -- this affects opening old sessions created with cinelerra's former (misguided) understanding of the dynamic range ending at -40dB. Cinelerra had/has the habit to just switch off the sound when reaching -40dB. On consumer grade Boxes this may seem fine, but when using Studio Monitors, you can hear a quite annoying "Click" at the start and end of /every/ fade and crossfade. But, on the other hand, would we change this "switch of at -40dB" behaviour, all sound tracks of all old sessions wouldn't be longer silent at places were the original author of these sessions intended them to be silent. Again, not noticeable on small PC speakers, quite noticeable on stuido speakers. Not, at the same time (two years ago) I was working on the "bezier patch" which improves the handling of the smooth fade (and camera+projector) curves quite to some degree. This was one of my attemts to fix/supply some features needed badly for more inclined work with cinelerra. (And as you all know, we learned the lession that wanting to repaire seemingly localized issiues quickly turns into a major undertaking -- finally this led us to where we are now with "Cin3") Pierre at that time helped me much to tidy up the bezier patch, split it up into parts so that it could be, at least partially accepted without breaking mergeability. This process created some tension, because I wanted to improve the source base and Pierre cared much more for staying alligned with upstream. Anyways, in the course of this we found out, that using the functionality I built into my patch (which we at that time expected to go "in" in some way) would also nicely solve the "96db" Problem, because it would allow us to set a new artificial interpolation node at -40dB while allow to retain the slope and curvature of the fade line the original author intended. Thus Pierre's partial patch for this problem was waiting on the inclusion of my patch, but the latter first costed much time, then came Cinelerra 2.1, I ported over my patch but Pierre then had already started to work on his thesis -- and I and my friends are using my privately patched Cinelerra version ever since (and doing sound mixing in Ardour anyways, so the click isn't a problem). Well -- I really don't know how to proceed with this issue now... cheers Hermann V. PS: Pierre Dumuid also did the patch to have separate zoom ranges for the video/audio fade and the projector and camera, which resolves most of the handling problems connected with this -96dB range limit. _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
