[FFmpeg-devel] [PATCH] frei0r wrapper

[Stefano Sabatini]

On date Sunday 2010-09-05 15:43:23 +0200, Michael Niedermayer encoded:
> On Mon, Aug 30, 2010 at 08:32:01PM +0200, Stefano Sabatini wrote:
> [...]
> 
> > +
> > +where @var{filter_path} is the path to the frei0r effect to load, and
> > + at var{param1}, @var{param2}, ... , @var{paramN} is a list of values
> > +separated by ":" which specify the parameters for the frei0r effect.
> > +
> > +frei0r filters are usually installed in @file{/usr/lib/frei0r-1/}.
> > +
> > +A frei0r effect parameter can be a boolean (whose values are specified
> > +with "true" and "false"), a double, a color (specified by the syntax
> > + at var{R} @var{G} @var{B}), a position (specified by the syntax
> > + at var{x} @var{y}) and a string.
> > +
> > +The number and kind of parameters depend on the loaded effect. If an
> > +effect parameter is not specified the default value is set.
> > +
> > +Follows some example:
> > + at example
> > +# apply the distort0r effect, set the first two double parameters
> > +frei0r=/usr/lib/frei0r-1/distort0r.so:0.5:0.01
> 
> requirering full pathes is lame when all filters are installed in like
> one place

Depends on the distro, also you can have the distro filters in one
place and your own filters into another dir.

> [...]
> > +static int set_param(AVFilterContext *ctx, f0r_param_info_t info, int index, char *param)
> > +{
> > +    Frei0rContext *frei0r = ctx->priv;
> > +    void *v;
> 
> > +    long double ld;
> 
> what are you trying to do?
> 
> 
> > +    double d;
> > +    f0r_param_color_t col;
> > +    f0r_param_position_t pos;
> > +    f0r_set_param_value_f f0r_set_param_value;
> > +
> > +    if (!(f0r_set_param_value = load_sym(ctx, "f0r_set_param_value")))
> > +        return AVERROR(EINVAL);
> > +
> 
> > +    switch (info.type) {
> > +    case F0R_PARAM_BOOL:
> 
> > +    {
> 
> is that way of placing it consistent?
> 
>     
> > +        if      (!strcmp(param, "true" )) d = 1.0;
> > +        else if (!strcmp(param, "false")) d = 0.0;
> > +        else goto fail;
> 
> we should allow something shorter than true false

on/off? Imho "true"/"false" is more readable then "1"/"0", especially
when you have a long list of params.

> 
> 
> > +        v = (void *)(&d);
> 
> the cast looks unneeded
> 
> 
> > +    }
> > +    break;
> > +
> > +    case F0R_PARAM_DOUBLE:
> > +    {
> > +        char *tail;
> > +        ld = strtold(param, &tail);
> > +        if (*tail || ld > DBL_MAX || ld < -DBL_MAX)
> > +            goto fail;
> > +        d = ld;
> > +        v = (void *)(&d);
> > +    }
> > +    break;
> > +
> 
> > +    case F0R_PARAM_COLOR:
> > +    {
> > +        if (sscanf(param, "%f %f %f", &col.r, &col.g, &col.b) != 3)
> > +            goto fail;
> > +        v = (void *)(&col);
> 
> dont the spaces need escaping on the command line?

Yes, suggestion for a better way of describing a color are welcome,
maybe r.g.b?
 
> [...]
> > +        switch (info.type) {
> > +        case F0R_PARAM_BOOL:
> > +            v = (void *)(&d);
> > +            f0r_get_param_value(frei0r->instance, v, i);
> > +            av_log(ctx, AV_LOG_INFO, "value:'%s'\n", d == 1.0 ? "true" : "false");
> > +            break;
> > +        case F0R_PARAM_DOUBLE:
> > +            v = (void *)(&d);
> > +            f0r_get_param_value(frei0r->instance, v, i);
> > +            av_log(ctx, AV_LOG_INFO, "value:'%f'\n", d);
> > +            break;
> > +        case F0R_PARAM_COLOR:
> > +            v = (void *)(&col);
> > +            f0r_get_param_value(frei0r->instance, v, i);
> > +            av_log(ctx, AV_LOG_INFO, "value:'%f %f %f'\n", col.r, col.g, col.b);
> > +            break;
> > +        case F0R_PARAM_POSITION:
> > +            v = (void *)(&pos);
> > +            f0r_get_param_value(frei0r->instance, v, i);
> > +            av_log(ctx, AV_LOG_INFO, "value:'%lf %lf'\n", pos.x, pos.y);
> > +            break;
> > +        default: /* F0R_PARAM_STRING */
> > +            v = (void *)s;
> > +            f0r_get_param_value(frei0r->instance, v, i);
> > +            av_log(ctx, AV_LOG_INFO, "value:'%s'\n", s);
> > +            break;
> > +        }
> 
> what is this good for?

Useful for debugging.

> [...]
> > +static av_cold void uninit(AVFilterContext *ctx)
> > +{
> > +    Frei0rContext *frei0r = ctx->priv;
> > +    f0r_destruct_f f0r_destruct;
> > +    f0r_deinit_f f0r_deinit;
> > +
> > +    if ((f0r_destruct = dlsym(frei0r->dll, "f0r_destruct")))
> > +        f0r_destruct(frei0r->instance);
> 
> all the dlsym shoudl be done in "init()" IMHO

I'll do.
-- 
FFmpeg = Fierce Fundamental Majestic Portable Emblematic Governor