Hello Daniel:
You wrote:
>Ok, now that i've looked at it a little deeper, the problem is obvious:
>
>QuickTime represents the duration of movies as a duple of TimeValue /
>TimeScale. The default timescale of movies opened from audio files,
>unfortunately, happens to be 600. When you open your audio file, the
>duration of the movie is set to 76/600 which, when converted to 8000
>Hz yields 1013.3333 samples (hence the 1014 you can extract). 77/600
>would be 1026.6666, which is more data than you have, hence the
>downward rounding.
At some point, QT should know the actual number of media samples in the
"movie".
I know that GetMediaTimeScale(theMedia) is returning the actual sample rate
(8000) and GetMediaDuration(theMedia) is returning the actual number of
samples (1024), so the information is knowable.
Perhaps QT could set the duration to 77/600 (a bit "too much") and then
return kQTMovieAudioExtractionComplete "early". Hey, an outsider can
pretend everything is simple, right? :-)
>
>This is just a fact of life. We had, apparently, tried importing
>audio files with the movie timescale set to the audio sample rate,
>and this broke a bunch of stuff. There are ways to programmatically
>load audio tracks into movies whose timescale is set arbitrarily, but
>i would have to research this to see if this could be made to work
>for your case.
Thanks for looking into this; our product (Igor) is a scientific data
analysis program. It is going to be difficult to explain to scientists why
the last bit of their audio field recordings has gone missing.
--
Jim "How does it work?" Prouty
Voice: (503) 620-3001, FAX: (503) 620-6754
Makers of IGOR Pro, scientific data analysis and graphing for Mac and PC
http://www.wavemetrics.com
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