Re: QTMovieLayer and renderInContext:

FROM : Bill Dudney
DATE : Fri Nov 23 14:41:52 2007

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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>>

>