xcode5 - Video slow motion using AVPLAYER in Cocoa Aplication -

i'm going start video slow motion using avplayer in cocoa application. example: can select start position , end position video. if play again video want slow motion start , end position . 1 please tech me how implement that. how select start position , end position , slow motion using avplayer.

you'll need add time observer player - addperiodictimeobserverforinterval:queue:usingblock:. called on regular intervals specify. you'll use know when player reaches start or end positions.

for start , end positions have store them somewhere in code , compare them in block of method. take in mind observer needs cmtime , many people bit confused it. here answers:

• trying understand cmtime
• trying understand cmtime , cmtimemake

i prefer work cmtime instead of seconds it's you.

then slow motion need set rate property of player whatever need - 0.5 make twice slower original speed, 0.25 make 4 times slower etc. value of 0 pause playback , value of 1 play normally. negative values same difference playback go reversed (towards begging) , values higher 1 (or -1) set playback faster normal.

so... while observing playback once currenttime property of player (or time parameter block) between start , end position set rate desired one. when currenttime out of range set rate 1 , video plays normal speed.

this is, think, easiest way. can use compositions , scale time ranges it's more complicated , if play video , don't need process afterwards think it's better stick simpler solution.

hope helps i'd suggest read more docs because avfoundation great framework unlimited possibilities there important things shouldn't miss when dealing it.