ios - Getting YUV from CMSampleBufferRef for video streaming -

i building ios video streaming chat application , library working requires send video data passing yuv (or guess ycbcr) data individually.

i have delegate set up, i'm not sure how individual yuv elements cmsamplebufferref. alot of apple guides seen, reference stuff capturing video frames uiimages though.

stream format

- (bool)setupwitherror:(nserror **)error {     avcapturedevice *videocapturedevice = [avcapturedevice defaultdevicewithmediatype:avmediatypevideo];     avcapturedeviceinput *videoinput = [avcapturedeviceinput deviceinputwithdevice:videocapturedevice error:error];      if (! videoinput) {         return no;     }      [self.capturesession addinput:videoinput];      self.processingqueue = dispatch_queue_create("abcdefghijk", null);      [self.dataoutput setalwaysdiscardslatevideoframes:yes];     nsnumber *value  = [nsnumber numberwithunsignedint:kcvpixelformattype_420ypcbcr8biplanarvideorange];      [self.dataoutput setvideosettings:[nsdictionary dictionarywithobject:value                                                                   forkey:(id)kcvpixelbufferpixelformattypekey]];     [self.dataoutput setsamplebufferdelegate:self queue:self.processingqueue];      return yes; }  - (void)captureoutput:(avcaptureoutput *)captureoutput didoutputsamplebuffer:(cmsamplebufferref)samplebuffer fromconnection:(avcaptureconnection *)connection {      cvimagebufferref imagebuffer = cmsamplebuffergetimagebuffer(samplebuffer);       if (! imagebuffer) {         return;     }        uint16_t width = cvpixelbuffergetheight(imagebuffer);     uint16_t height = cvpixelbuffergetheight(imagebuffer);      uint8_t yplane[??] = ???     uint8_t uplane[?] = ???     uint8_t vplane[?] = ???      [self.library sendvideoframetofriend:self.friendnumber width:width height:height                                 yplane:yplane                                 uplane:uplane                                 vplane:vplane                                  error:nil]; } 

does have examples or links can figure out?

update according https://wiki.videolan.org/yuv there shall more elements of y there u/v. library confirms well, nothing below:

 * y - plane should of size: height * width  * u - plane should of size: (height/2) * (width/2)  * v - plane should of size: (height/2) * (width/2) 

updated i've read how yuv buffer composed , how read it. made sure dont malloc on every frame.

have fun! ;)

//int bufferwidth = cvpixelbuffergetwidth(pixelbuffer);  int yheight = cvpixelbuffergetheightofplane(pixelbuffer,0); int uvheight = cvpixelbuffergetheightofplane(pixelbuffer,1);  int ywidth = cvpixelbuffergetwidthofplane(pixelbuffer,0); int uvwidth = cvpixelbuffergetwidthofplane(pixelbuffer,1);  int ybpr = cvpixelbuffergetbytesperrowofplane(pixelbuffer, 0); int uvbpr = cvpixelbuffergetbytesperrowofplane(pixelbuffer, 1);  int ysize = yheight * ybpr ; int uvsize = uvheight * uvbpr ;  static unsigned char *ypane; if(!ypane)    ypane = (unsigned char*)malloc(ysize); static unsigned char *upane; if(!upane)    upane = (unsigned char*)malloc(uvsize); static unsigned char *vpane; if(!vpane)    vpane = (unsigned char*)malloc(uvsize);  unsigned char *ybase = cvpixelbuffergetbaseaddressofplane(ypane, 0); unsigned char *ubase = cvpixelbuffergetbaseaddressofplane(upane, 1; unsigned char *vbase = cvpixelbuffergetbaseaddressofplane(vpane, 2);  for(int y=0,y<yheight;y++) {    for(int x=0,x<ywidth;x++)    {       ypane[y*ywidth+x]=ybase[y*ybpr+x];    }  }  for(int y=0,y<uvheight;y++) {    for(int x=0,x<uvwidth;x++)    {       upane[y*uvwidth+x]=ubase[y*uvbpr+x];       vpane[y*uvwidth+x]=vbase[y*uvbpr+x];    }  }