Sets a caps in allocation query which are different from the set pad's caps. Use this function before calling gstaudio.audio_decoder.AudioDecoder.negotiate. Setting to null the allocation query will use the caps from the pad.
a #GstCaps or null
Sets a caps in allocation query which are different from the set pad's caps. Use this function before calling gstaudio.audio_decoder.AudioDecoder.negotiate. Setting to null the allocation query will use the caps from the pad.