[Developpers wanted] : create a Stereo2Mono plugin for BeSweet

[Kurtnoise]

Hi,

I'm planning to add some features into BeLight that's why I would like to submit a request to experts coders :

To have the possibility to transcode AC3 files to Vorbis mono files. It could be very interesting I think. ;) Due to the fact that BeSweet can't natively encode in vorbis mono, the best thing is to create some plugins. DSPGuru had made one : Mono2Stereo (http://besweet.notrace.dk/BS_M2S.zip) (sources included). It could be a good start point to develop a new one : Stereo2Mono, isn't it ?

My knowledge in C is very limited (I tried some things, but nothing worked really...:( ) that's why I call you to help simple users like me and all the community of course. ;) BeSweet is a really a great tool, so it will be shame to let down his development.

Thanks for your attention.

[MaroonMike]

What happened to DSPGuru? Did he call it quits?

[Kurtnoise]

Originally posted by MaroonMike
What happened to DSPGuru? Did he call it quits?
I think yes... (http://forum.doom9.org/showthread.php?s=&threadid=50499&highlight=bye+bye+DSPGuru) :(

[dcoder]

My knowledge in C is very limited
Maybe some Delphicode (http://files.dsp-worx.de/bs_s2m.zip) might help ;)

[Kurtnoise]

sweeeeeeeeet...:D Thank you very much dcoder.

I'll try it asap. ;)

[Kurtnoise]

I'm testing....the file duration is divided by 2 and playback speed is multiplied by 2. :( Any idea ?

[dcoder]

well, it´s because the plugin mixes channel 1 and 2 to only 1 channel. I haven't seen anything in besweets sdk to change the number of channels. It will help to rewrite "Simple" to:

for i := 0 to (Size shr 1) -1 do
begin
TempBuffer[i shl 1] := (Buffer[i shl 1] + Buffer[i shl 1 + 1]) / 2;
TempBuffer[i shl 1 +1] := TempBuffer[i shl 1]
end;

FOutPut(@TempBuffer, Size);

this will still create a 2 channel file, but with each channel equal.

[Kurtnoise]

I added the line code like you said but the problem remains. Here (http://dspguru.notrace.dk/BS_Downmix.zip) is the source plugin to downmix channels. Hope this help...

[E-Male]

i worked on somethign similar once
i'll look at your code later and see if i can add something to make it work

[dcoder]

hmm..the code is the same as in my original zip file. There is propably just a "switch" in the command line missing to tell besweet that it contains only one channel after processing, but i can't seem to find it. The code i´ve posted above does work very well for me, but it creates a 2 channel file (dual mono).

[E-Male]

i think the problem is that besweet doesn't have a 1ch switch

going to mono isn't the problem algorythmwise

but it's interprted as stereo, so it's double speed, because the mono part is split into left and right