set property value from a string

[Matthew Waters]

gst_parse_launch() uses gst_util_set_object_arg():
https://gstreamer.freedesktop.org/documentation/gstreamer/gstutils.html?gi-language=c#gst_util_set_object_arg

On 23/7/20 8:00 pm, Gary Metalle wrote:
>
> Is there a way to set a property value from a given string, i.e
> convert from G_STRING to whatever type is required for that property?
>
>
> I have a string such as the following:
>
>
> "byte-stream=TRUE rc-lookahead=0 tune=zerolatency
> speed-preset=ultrafast sync-lookahead=0"
>
>
> That I split up into name/value pairs and then need to set each property.
>
>
> I first use g_object_class_find_property() to find out if the named
> property exists and this is ok and it returns a GParamSpec which tells
> me the type of the property.
>
>
> I've tried using g_value_transform() but this only seems to be able to
> cope with simple stuff like converting a double to an int etc. Is
> there no simple way to convert say a string of "TRUE" to a gboolean?
>
> I have also tried g_param_convert() but didn't get anywhere with that
> either.
>
>
> Someone must be doing it somehow because if you pass a pipeline string
> to gst_parse_launch() then it has to cope with this. It would be easy
> to custom write something for "TRUE"/"FALSE" to gboolean but not so
> for the enum types and the x264enc plugin has quite a few of those.
>
>
> On a positive note I think g_param_value_validate() works when you
> want to check that a given value is within the range for the defined
> property, but it implies you've converted it to the correct type first.
>
>
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