iphone - How to generate images from already recorded video using AVAssetImageGeneratorCompletionHandler block? -


this might silly question sorry newbie iphone.

i want generate images every frames of video , display in uiscrollview inside uiimageview.

when trying getting memory warning , app crashes.

below code.

- (ibaction)oncamerabuttonpressed:(id)sender {     // initialize uiimagepickercontroller select movie camera roll.     uiimagepickercontroller *videopicker = [[uiimagepickercontroller alloc] init];     videopicker.delegate = self;     videopicker.modalpresentationstyle = uimodalpresentationcurrentcontext;     videopicker.sourcetype = uiimagepickercontrollersourcetypesavedphotosalbum;     videopicker.mediatypes = @[(nsstring*)kuttypemovie];     [self presentviewcontroller:videopicker animated:yes completion:nil]; }  #pragma mark image picker controller delegate  - (void)imagepickercontroller:(uiimagepickercontroller *)picker     didfinishpickingmediawithinfo:(nsdictionary *)info {    [self dismissviewcontrolleranimated:yes completion:nil];     currentvideourl = info[uiimagepickercontrollerreferenceurl];     //video url = assets-library://asset/asset.mov?id=d0a4a3ee-c5f3-49c8-9e45-adf775b9fa8c&ext=mov     //nslog(@"video url = %@",currentvideourl);     //imageindex = 0;     (uiimageview *subview in thumbnailscrollview.subviews)     {         [subview removefromsuperview];     }     [self generatethumbnailsfromvideourl:currentvideourl];     //[self generateavassetthumbnails:currentvideourl];     //[self appleimagegenerator:currentvideourl];     }  - (void)generatethumbnailsfromvideourl:(nsurl *)videourl {     avurlasset *asset=[[avurlasset alloc] initwithurl:videourl options:nil];     //nslog(@"video duration %lld seconds",asset.duration.value/asset.duration.timescale);     int videoduration = (asset.duration.value/asset.duration.timescale);      if (cmtimearray.count>0) {         [cmtimearray removeallobjects];     }     (int = 0; i<videoduration; i++)     {         int64_t tempint = i;         cmtime tempcmtime = cmtimemake(tempint,1);         int32_t interval = 15;         (int j = 1; j<16; j++)         {             cmtime newcmtime = cmtimemake(j,interval);             cmtime addition = cmtimeadd(tempcmtime, newcmtime);             [cmtimearray addobject:[nsvalue valuewithcmtime:addition]];         }     }     //nslog(@"array of time %@ count = %d",cmtimearray, cmtimearray.count);     /*for(int t=0;t < asset.duration.value;t++) {         cmtime thumbtime = cmtimemake(t,asset.duration.timescale);         nsvalue *v=[nsvalue valuewithcmtime:thumbtime];         [cmtimearray addobject:v];     }     nslog(@"array of time %@ count = %d",cmtimearray, cmtimearray.count);*/     __block int = 0;     //__block uiimage *currentimage = nil;     avassetimagegeneratorcompletionhandler handler = ^(cmtime requestedtime, cgimageref im, cmtime actualtime, avassetimagegeneratorresult result, nserror *error){         if (result == avassetimagegeneratorsucceeded) {             // currentimage = [uiimage imagewithcgimage:im];             //[framesarray addobject:[uiimage imagewithcgimage:im]];             [self performselectoronmainthread:@selector(insertimagetoscrollview:) withobject:[uiimage imagewithcgimage:im] waituntildone:no];         }         else             nslog(@"ouch: %@", error.description);         i++;         imageindex = i;         if(i == cmtimearray.count) {             //[self performselectoronmainthread:@selector(insertimagetoscrollview:) withobject:framesarray waituntildone:yes];         }     };      // launching process...     self.generator = [[avassetimagegenerator alloc] initwithasset:asset];     self.generator.appliespreferredtracktransform=true;     self.generator.requestedtimetolerancebefore = kcmtimezero;     self.generator.requestedtimetoleranceafter = kcmtimezero;     self.generator.maximumsize = cgsizemake(40, 40);     [self.generator generatecgimagesasynchronouslyfortimes:cmtimearray completionhandler:handler];     }  -(void)insertimagetoscrollview:(uiimage *)image {     int xposition = (5*imageindex)+(width*imageindex)+offset;     uiimageview *currentimageview = [[uiimageview alloc]initwithframe:cgrectmake(xposition, 5, width, width)];     currentimageview.tag = imageindex+10;     currentimageview.image = image;     [thumbnailscrollview addsubview:currentimageview];     [thumbnailscrollview setcontentsize:cgsizemake(xposition+width+5,thumbnailscrollview.frame.size.height)]; }

you loading images view, few displayed @ 1 given time. depending on amount of images, take lot of memory.

you consider following approach:

generate images , write them local storage, store file-urls of images in array.

now scrollview, add images needed, when scroll next ones. when adding images, load them disk , add them view. take @ example code horizontal infinite scrollview: https://code.google.com/p/iphone-infinite-horizontal-scroller.

you use ordinary uitableview custom cell, showing image.


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