opencv - HTTP live stream AVAsset -

i implementing n http live streaming player osx using avplayer. able stream seek , duration timing etc. want take screen shots , process frames using opencv. went using avassetimagegenerator. there no audio , video tracks avasset associated player.currentitem.

the tracks appearing in player.currentitem.tracks. not able sue avassetgenerator. can find out solution extract screenshots , individual frames in such scenario?

please find code below how initiating http live stream

thanks in advance.

nsurl* url = [nsurl urlwithstring:@"http://devimages.apple.com/iphone/samples/bipbop/bipbopall.m3u8"]; playeritem = [avplayeritem playeritemwithurl:url];  [playeritem addobserver:self forkeypath:@"status" options:0 context:avspplayerstatuscontext]; [self setplayer:[avplayer playerwithplayeritem:playeritem]]; [self addobserver:self forkeypath:@"player.rate" options:nskeyvalueobservingoptionnew context:avspplayerratecontext]; [self addobserver:self forkeypath:@"player.currentitem.status" options:nskeyvalueobservingoptionnew context:avspplayeritemstatuscontext]; avplayerlayer *newplayerlayer = [avplayerlayer playerlayerwithplayer:[self player]]; [newplayerlayer setframe:[[[self playerview] layer] bounds]]; [newplayerlayer setautoresizingmask:kcalayerwidthsizable | kcalayerheightsizable]; [newplayerlayer sethidden:yes]; [[[self playerview] layer] addsublayer:newplayerlayer]; [self setplayerlayer:newplayerlayer]; [self addobserver:self forkeypath:@"playerlayer.readyfordisplay" options:nskeyvalueobservingoptioninitial | nskeyvalueobservingoptionnew context:avspplayerlayerreadyfordisplay]; [self.player play];     

following how checking whether video track present asset

case avplayeritemstatusreadytoplay:                  [self settimeobservertoken:[[self player] addperiodictimeobserverforinterval:cmtimemake(1, 10) queue:dispatch_get_main_queue() usingblock:^(cmtime time) {                     [[self timeslider] setdoublevalue:cmtimegetseconds(time)];                     nslog(@"%f,%f,%f",[self currenttime],[self duration],[[self player] rate]);                     avplayeritem *item = playeritem;                     if(item.status == avplayeritemstatusreadytoplay)                     {                     avasset *asset = (avasset *)item.asset;                     long audiotracks = [[asset tracks] count];                     long videotracks = [[asset availablemediacharacteristicswithmediaselectionoptions]count];                      nslog(@"track info audio = %ld,video=%ld",audiotracks,videotracks);                     }                 }]];                    avplayeritem *item = self.player.currentitem;                 if(item.status != avplayeritemstatusreadytoplay)                     return;                 avurlasset *asset = (avurlasset *)item.asset;                 long audiotracks = [[asset trackswithmediatype:avmediatypeaudio]count];                 long videotracks = [[asset trackswithmediatype:avmediatypevideo]count];                  nslog(@"track info audio = %ld,video=%ld",audiotracks,videotracks); 

this older question in case needs have answer

avurlasset *asset = /* asset here! */; avassetimagegenerator *generator = [[avassetimagegenerator alloc] initwithasset:asset]; generator.requestedtimetoleranceafter =  kcmtimezero; generator.requestedtimetolerancebefore =  kcmtimezero; (float64 = 0; < cmtimegetseconds(asset.duration) *  /* put fps of source video here */ ; i++){     @autoreleasepool {         cmtime time = cmtimemake(i, /* put fps of source video here */);          nserror *err;         cmtime actualtime;         cgimageref image = [generator copycgimageattime:time actualtime:&actualtime error:&err];          // want image, example save uiimage         uiimage *generatedimage = [[uiimage alloc] initwithcgimage:image];          cgimagerelease(image);     } } 

you can fps of video using code:

float fps=0.00; if (asset) {     avassettrack * videoatrack = [asset trackswithmediatype:avmediatypevideo][0];     if(videoatrack)     {         fps = [videoatrack nominalframerate];     } } 

hope helps asking how frames video or specific (with cmtime example) frames. please bear in mind, saving frames array can impact memory hardly!