basesink: improve comments
basesink: improve comments

jpakkane/gstreamer,cablelabs/gstreamer,cfoch/gstreamer,jpxiong/gstreamer,krieger-od/gstreamer,lubosz/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,cablelabs/gstreamer,Lachann/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,collects/gstreamer,justinjoy/gstreamer,jpxiong/gstreamer,krieger-od/gstreamer,collects/gstreamer,justinjoy/gstreamer,centricular/gstreamer,Lachann/gstreamer,cablelabs/gstreamer,centricular/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,Lachann/gstreamer,justinjoy/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,cfoch/gstreamer,mparis/gstreamer,cablelabs/gstreamer,jpakkane/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,krichter722/gstreamer,Lachann/gstreamer,surround-io/gstreamer,krichter722/gstreamer,collects/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,ensonic/gstreamer,krichter722/gstreamer,ensonic/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,surround-io/gstreamer,StreamUtils/gstreamer,lubosz/gstreamer,surround-io/gstreamer,krieger-od/gstreamer,surround-io/gstreamer,lubosz/gstreamer,lubosz/gstreamer,surround-io/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,cfoch/gstreamer,krichter722/gstreamer,mparis/gstreamer,cfoch/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,jpxiong/gstreamer,krieger-od/gstreamer,collects/gstreamer,StreamUtils/gstreamer,ensonic/gstreamer,lovebug356/gstreamer,shelsonjava/gstreamer,lovebug356/gstreamer,jpxiong/gstreamer,mparis/gstreamer,lubosz/gstreamer,mparis/gstreamer,collects/gstreamer,ensonic/gstreamer,justinjoy/gstreamer,mparis/gstreamer,justinjoy/gstreamer