Re: QTMovieLayer and renderInContext:

FROM : Bill Dudney
DATE : Fri Nov 23 16:27:18 2007

Sure,

here is my awakeFromNib where I setup the movie and layer

- (void)awakeFromNib {
    NSString *moviePath = [[NSBundle mainBundle] 
pathForResource:@"MyMovie" ofType:@"m4v"];
    NSError *error = nil;
    movie = [QTMovie movieWithFile:moviePath error:&error];
    QTMovieLayer *layer = [QTMovieLayer layerWithMovie:movie];
    layer.backgroundColor = [self black];
    layer.beginTime = 2.0f;
    [self setLayer:layer];
    [self setWantsLayer:YES];
}

and the play action;

- (void)play:(id)sender {
    [movie play];
}

With the beginTime set to 2.0 seconds the movie is black for the first 
2 seconds (about, I did not time it) then a frame renders. Then it is 
black for 2 more seconds then it renders another frame. I tried 
setting this value to other values and the intermittent frame 
rendering seems to track with the beginTime property (i.e if I set it 
to 0.25 then I get a frame every .25 seconds).

During the whole play back however the audio is rendering.

If I set the timeOffset on the layer the playback happens from the 
beginning of the movie. IOW the timeOffset  property seems to have no 
affect on movie play back.

HTH,

-bd-
http://bill.dudney.net/roller/objc

> OK,
>
> Thanks for trying anyway Bill.  I do appreciate it.
>
> Just one part of the sentence below I didn't understand.  You said 
> '...and what I get is every few frames rendered...', can you please 
> explain in more detail what you did exactly, and whether or not you 
> had the QTMovie playing or static?
>
> thanks
>
> --
> John Clayton
> http://www.coderage-software.com/
>
>
>
> On 23/11/2007, at 2:41 PM, Bill Dudney wrote:
>

>> Ah,
>>
>> Sorry no enlightenment here...
>>
>> But my curiosity was piqued so I had to spend some time messing 
>> with it. I'm not surethis will help you but figured I'd share what 
>> I found in case it does.
>>
>> I tried setting the beginTime on my QTMovieLayer and what I get is 
>> every few frames are rendered (looks like ever beginTime'th frame) 
>> and all the audio is played. timeOffset does not appear to affect 
>> my video at all.
>>
>> HTH,
>>
>> -bd-
>> http://bill.dudney.net/roller/objc
>>
>> On Nov 22, 2007, at 7:24 AM, John Clayton wrote:
>>

>>> Hi Bill, thanks for the input... buuuuuut:
>>>
>>> Nope, my aim is somewhat different.
>>>
>>> I need a movie in a view.  I want the frames of the movie to be in 
>>> a layer.  I do *not* want it to autoplay, and I *do* want to tell 
>>> the layer that the beginTime and duration are X and Y 
>>> respectively, and I do want to be able to control the specific 
>>> frame that is represented on the layer from that movie.
>>>
>>> Try thinking about putting a few movies across a timeline, and 
>>> telling them to start/end at a particular time along that 
>>> timeline.  This is what I'm trying to do.
>>>
>>> What I've got going so far:
>>> a) a QTMovieLayer (with INF/default duration), rendering a movie 
>>> (NOT autoplay on construction)
>>> b) a slider on a view that tells the NSMovie what render time is, 
>>> via the setCurrentTime:(QTTime) method.
>>>
>>> this works.  and I gotta say, beautifully.
>>>
>>> where it all breaks down is in the following:
>>> c) set the QTMovieLayers beginTime to something (anything)
>>>
>>> now nothing is rendered at all.
>>>
>>> So far, my belief/understanding is as follows - but please do feel 
>>> free to enlighten me:
>>>
>>> When using (a) and (b), the Core Anim engine sees that the 
>>> QTMovieLayer has an infinite duration, and thus, the movie is a 
>>> valid candidate to be rendered by the Core Anim system.  Every 
>>> time the 'rendering time' is modified by the slider, the 
>>> currentTime of the NSMovie is changed - and QTMovieLayer (being 
>>> async in nature) renders the new frame properly.
>>>
>>> I'm still not clear why settings a beginTime (as in (c) above)) 
>>> causes the animation to do nothing.
>>>
>>> --
>>> john
>>>
>>>
>>> On 22/11/2007, at 1:27 PM, Bill Dudney wrote:
>>>

>>>> Hi John,
>>>>
>>>> I'm not sure that I understand the question but if all you want 
>>>> to do is put a movie layer into a view I have a simple example 
>>>> here that works for me;
>>>>
>>>> - (void)awakeFromNib {
>>>>    NSString *moviePath = @"your path here";
>>>>    NSError *error = nil;
>>>>    movie = [QTMovie movieWithFile:moviePath error:&error];
>>>>    [movie autoplay];
>>>>    QTMovieLayer *layer = [QTMovieLayer layerWithMovie:movie];
>>>>    [self setLayer:layer];
>>>>    [self setWantsLayer:YES];
>>>> }
>>>>
>>>> This awakeFromNib is from my view class that takes up the whole 
>>>> window. The movie plays when the app starts.
>>>>
>>>> In the example (that I've not posted yet but will soon) on my 
>>>> blog I have a 'play' button that sits in the view that the movie 
>>>> plays on and it works like a champ.
>>>>
>>>> HTH,
>>>>
>>>> -bd-
>>>> http://bill.dudney.net/roller/objc
>>>>
>>>> On Nov 21, 2007, at 11:47 PM, John Clayton wrote:
>>>>

>>>>> Hi All,
>>>>>
>>>>> I am trying to use the CALayer renderInContext: call to put the 
>>>>> contents of a QTMovieLayer instance onto a view, but I get a 
>>>>> blank view - nothing renders.
>>>>>
>>>>> Is this call supposed to work for a QTMovieLayer?  I suppose the 
>>>>> question could be expanded to: is the renderInContext: method 
>>>>> supposed to work for any type of open-gl based layer class?
>>>>>
>>>>> Thanks,
>>>>> --
>>>>> John Clayton
>>>>> http://www.coderage-software.com/
>>>>>
>>>>>
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>>>>

>>>

>>

>