Initialize capabilities probing API based on AVOption API.
avdevice_capabilities_free() must be called when query capabilities API is
not used anymore.
@paramout caps Device capabilities data. Pointer to a NULL pointer must be passed.
@param s Context of the device.
@param device_options An AVDictionary filled with device-private options.
On return this parameter will be destroyed and replaced with a dict
containing options that were not found. May be NULL.
The same options must be passed later to avformat_write_header() for output
devices or avformat_open_input() for input devices, or at any other place
that affects device-private options.
Initialize capabilities probing API based on AVOption API.
avdevice_capabilities_free() must be called when query capabilities API is not used anymore.
@paramout caps Device capabilities data. Pointer to a NULL pointer must be passed. @param s Context of the device. @param device_options An AVDictionary filled with device-private options. On return this parameter will be destroyed and replaced with a dict containing options that were not found. May be NULL. The same options must be passed later to avformat_write_header() for output devices or avformat_open_input() for input devices, or at any other place that affects device-private options.
@return >= 0 on success, negative otherwise.