Re: Text track in QTMovie
Re: Text track in QTMovie
- Subject: Re: Text track in QTMovie
- From: douglas welton <email@hidden>
- Date: Sun, 14 Dec 2008 21:54:04 -0500
when you say it won't show you the "track names" do you mean:
a) your NSLog() function is failing and nothing is printed
b) NSLog() prints something, but the value of string appears to be
either nil or empty (which one?)
c) you really want the name of the track (i.e., the thing displayed
in the QT Player) and not the text in each sample. If this is the case
then we have to do something entirely different ;^}
d) all of the function calls succeed and when examined in the debugger
you can see the values for size and chars[] are valid but your
NSString cannot be properly constructed.
Can you clarify? BTW, what values are you seeing in the debugger?
On Dec 14, 2008, at 8:33 PM, Joe Turner wrote:
Okay, so I did what you said, but yet, it still won't show me the
track names. Here is my code:
Media media = [[[[[movieView movie]
tracksOfMediaType:QTMediaTypeText] objectAtIndex:0] media]
quickTimeMedia];
TimeValue64 timeValue = 0;
TimeValue64 duration = 0;
GetMediaNextInterestingDecodeTime(media, nextTimeMediaSample +
nextTimeEdgeOK, timeValue, fixed1, &timeValue, &duration);
ByteCount size;
GetMediaSample2(media, NULL, 0, &size, timeValue, NULL, NULL, NULL,
nil, nil, 1, NULL, NULL);
char chars[size];
GetMediaSample2(media, &chars, size, NULL, timeValue, NULL, NULL,
NULL, nil, nil, 1, NULL, NULL);
NSString *string = [[NSString alloc] initWithBytes:chars
length:size encoding:NSUTF8StringEncoding];
NSLog(@"String: %@", string);
Thanks,
Joe
On Dec 14, 2008, at 7:03 PM, douglas welton wrote:
Hi Joe,
Since you didn't define "easy" or tell me what you'd tried, then
I'll have to make some assumptions about what you know. I will
assume that you have read the documentation on QT media samples.
The basic steps:
Get the text track.
Get the track media.
loop thru the media samples using a function like
GetMediaNextInterestingDecodeTime() with the parameters of your
choice
Use GetMediaSample2() to get the data/length associated with the
text sample.
Create an NSString with the bytes/length returned in the previous
call
regards,
douglas
On Dec 14, 2008, at 7:26 PM, Joe Turner wrote:
I have a QTMovie (that is valid), and it has a text track. I am
wondering if there is any easy way to get the contents of the text
track into an NSString.
Thanks,
Joe
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