[FFmpeg-devel] [PATCH] Implement options parsing for avfilter filters

[Stefano Sabatini]

On date Sunday 2009-04-19 13:11:36 +0200, Vitor Sessak encoded:
> Stefano Sabatini wrote:
>> Hi,
>> as recently discussed, plus application to the libavfilter-soc scale
>> filter.
>>
>> I'm not very happy with the parse_options.[hc] name, suggestions are
>> welcome.
>
>>  static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
>>  {
>>      ScaleContext *scale = ctx->priv;
>>      char sws_opts[256];
>> -    char *p;
>>       /* default to no scaling */
>> +    scale->av_class = &vf_scale_class;
>> +    av_opt_set_defaults2(scale, 0, 0);
>> +
>>      scale->w =
>>      scale->h = 0;
>>  @@ -55,11 +69,11 @@
>>      if(args)
>>          sscanf(args, "%d:%d:%255s", &scale->w, &scale->h, sws_opts);
>>  -    if ((p = strstr(sws_opts, "sws_flags="))) {
>> -        char sws_flags[256];
>> -        sscanf(p, "sws_flags=%255[^:]", sws_flags);
>> +    if (avfilter_parse_options(scale, sws_opts) < 0)
>
> Why not simply pass ctx to avfilter_parse_options()? It would avoid the  
> need of the CREATE_FILTER_CLASS macro...

I considered that solution but I don't believe it can be achieved.

av_opt_set* functions work by setting values in an AVClass context,
with respect to the the offset defined in that context.

When I define the options I need to pass the offsets of the ScaleContext
struct, since I cannot extend AVFilterContext to contain fields
specific to each filter.

Regards.
-- 
FFmpeg = Faboulous Fostering Minimalistic Puristic Enlightened Genius