[PD-dev] tilde object rework ideas

[IOhannes m zmoelnig]

On 9/2/22 01:00, Christof Ressi wrote:
> Hi Miller,
> 
> this sounds great! First-class multi-channel support would be a real 
> game changer.


yes. that would be so cool!


>> typedef struct _signal
>> {
>>      int s_n;            /* *TOTAL* number of points in the array */
>>      t_sample *s_vec;    /* the array */
>>      t_float s_sr;       /* *TOTAL* samples per second */
[...]
>>      t_float s_rate;     /* sample rate */
>>      int s_length;       /* number of points in each channel */
>>      int s_nchans;       /* number of channels */
>>      int s_overlap;      /* number of times each sample will appear */
>> }
> Personally, I would keep s_n as the number of samples /per channel/. The 
> total number of samples is simply s_n * s_nchans. Existing externals - 
> that do not know about s_nchans - would effectively operate on the first 

i think the idea is that with "s_n = s_nchans * s_length" existing 
externals would automatically process *all* channels.

that's nice if the external does not do any delays or so (as they would 
automatically become multi-channel aware), but not so nice if they *do* 
things in the time domain (as there would be weird cross-talk between 
the channels).

i'm not favouring any of the two approaches, just wanted to point their 
differences.

i somewhat agree with christof's implication, that it's probably best to 
not have redundant data in the struct.
- 's_n = s_nchans * s_length' (or 's_totalsamples = s_nchans * s_n')
- 's_sr = s_rate * s_overlap * s_nchans'

(my issue being, that with redundancy it's more likely to have 
inconsistent data; what if the struct says 's_n = 128; s_nchans = 3; 
s_length = 1024'?)

apart from that:
probably "s_length" might be called "s_frames" as this seems to be the 
less ambiguous term.

and i would personally prefer "s_samplerate" and "s_channels".
that would make for an easy distinction: the abbreviated names "s_n" and 
"s_sr" are the convoluted ones, whereas the long names have the data 
you'd expect.



> channel and ignore the rest. Newer multi-channel-aware externals, on the 
> other hand, may use all the channels.
> 
> I also think that DSP objects would need a new API method to create 
> multi-channel /outputs/. The general idea is that the /input /channel 
> counts are taken from upstream, but the /output /channel counts are 
> specified by the object and passed downstream. (There might be objects 
> where input and output channel count differs; any kind of 
> merger/splitter/mixer objects comes to my mind.)

+1

vgmasdrf
IOhannes
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