On Fri, Feb 10, 2012 at 12:05:36AM +0100, Alexandre H wrote:
You'll face other problems preventing you from doing everything with
aucat. First, there's no reverb, which is necessary to create the
spacial feel, volume changes are too abrupt (cause small clicks) and
not real-time.
Implementing pan, effects and smooth parameter changes would bloat
aucat/sndiod. IMO the way to go is to handle processing in small
programs (with a simple record->process->play loop) and keep sndiod
only for routing the signal to the hardware or other programs.
Currently that's the way I handle some effects, I write small programs
that apply effects on the record stream to send the result in
real-time on the play stream. Then I use -mmon to record the result in
a file. Not very flexible, but good enough to test the concept.
If I understand what you are doing, perhaps you have another way.
Noatun doesn't make the deal ?
afaics noatun can't apply effects in real-time and is not very
lightweight.
When I wrote it can apply effects in "real-time" I meant this :
I play an audio file. While it plays it I can do the following :
I go to the menu Settings and select Effects. I add the effect
Arts::Synth_FREEVERB for example. I hear the audio changing
"immediatly" as expected. If I change the value of a parameter the
audio change "immediatly" as expected. I can change the position of the
playing-cursor without audible delay. It's interactive and the audible
audio quality doesn't change (assuming the activity of other parts of
the system doesn't change sufficiently). AFAICS the effect is applied
online. Noatun and Kaffeine can do this "real-time".
Sure, this interactive mode has some drawbacks and adding the audio
output recording in a new file will slowdown more or less the whole
process and perhaps decrease the audible audio quality (and if too many
process eat the CPU the "real-time" will end). At least for this last
reason it's certainly better to use batch mode (1 process offline) with
a command (sox for example) launched from a CLI.
The interactive mode has an obvious advantage : instead of launching
many times the same command with differents values in order to find the
best values, it's certainly easier to use a player with this
"real-time" capability. This interactive mode is useful not only for
listening music or playing with effects but also for discovering,
experimenting and testing filters (and GUI isn't mandatory, it can be
done in console mode with a keyboard only). This is why I proposed
Noatun (it should exists ligtherweight player with this capability).
I would like to go further on this point, I will stay brief :
An audio editor can use this 2 modes. The user searchs the best values
in interactive mode (without recording) and when he pushs the "Save"
button, the editor launch in background something like sox with this
values, wich converts the input file and give the output file (batch
mode). The editor has the advantages of this 2 modes without their
drawbacks.
If someone want to develop a new audio filtering editor he can
implement this principle on any player with this "real-time" capability
instead of developing a new one from scratch. Noatun seems to be a good
candidat. The player with the UI is already done and it works well, so
less work to do.
