[PD-dev] non-2^n blocksizes (was Re: [ pure-data-Feature Requests-3578019 ] I'd like to...)

[IOhannes m zmoelnig]

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On 2012-10-24 02:56, Miller Puckette wrote:
> I think the most nearly correct thing to do would be to change the 
> signal structure to add an ?allocated-size" field, and put what is 
> now calcsize in the s_n field of the signal.

<m_pd.h>
typedef struct _signal
{
    int s_n;            /* number of points in the array */
    t_sample *s_vec;    /* the array */
    t_float s_sr;         /* sample rate */
    int s_refcount;     /* number of times used */
    int s_isborrowed;   /* whether we're going to borrow our array */
    struct _signal *s_borrowedfrom;     /* signal to borrow it from */
    struct _signal *s_nextfree;         /* next in freelist */
    struct _signal *s_nextused;         /* next in used list */
    int s_vecsize;      /* allocated size of array in points */
} t_signal;
</m_pd.h>

now i haven't recently checked the mechanics how all these variables
are used internally, but according to the comments i would have
guessed that, "s_vecsize" is the "allocated-size" field, and "s_n" is
the actual (to-be-computed) vectorsize.



> 
> I'm not 100% sure I can change the size of the signal structure 
> without breaking binary compatibility with older objects.

i think that "t_signal" is used by reference everywhere, which would
grant binary compatibility, as long as you only add the end of the struct.

> However, there's other stuff I want to add (to support objects 
> being able to detect when there's no signal connected to an
> input). I think when I make that change I can

more important for me would be fields to separate
overlap/resampling/samplerate.
PLLLLLEAASE!


> try making the non-power-of-two thing work too.  But I'm not sure 
> anyone will ever use it - there are other ways to process images 
> these days :)

there have been other ways to process images before...
i still would love to see non-2^n blocksizes, ideally allowing
reblocking to sub-patches if one blocksize is an integer multiple of
the other.


mfgasdr
IOhannes


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