[vorbis-dev] Quicktime Component

[Kevin Marks]

At 8:14 PM -0400 7/23/01, Nick D'Amato wrote:
>On 7/23/01 7:52 PM, Segher Boessenkool said:
>
>>  I read from the dataref associated with my media, and calculate offsets and
>>  ogg page size from the ogg page headers.  That seems to work...  although
>>  QT doesn't seem to like a zero-length in time, non-zero-length in bytes
>>  sample...  I need some trickery for that (and similar cases).
>
>Yea there are some secrets of QT... we have to beat up Apple engineers to
>get them (sorry Kevin =)

If this is for codebooks, I told you my suggested workaround there - 
add them as SoundDescriptionExtensions. There isn't a concept of 
inter-sample dependency for audio in QT, so having the codebooks in 
magic samples means your file will stop working when edited.
Try this in QT Player Pro (or another editing-enabled app):

Import a file. Select the last few seconds. Copy, New, Paste, save as 
self-contained.

Then try playing the new file. If it doesn't play, you have the 
problem I'm talking about.

At 7:39 PM -0400 7/23/01, Nick D'Amato wrote:
>
>Every time I open it in iTunes, it comes in saying 'song name (converted)'.
>I guess iTunes will need some changes too.

That sounds like Mac easy Open doing things behind your back. If you 
don't set the 'import in place' flags, it converts the ogg file to a 
temporary movie file.

>Right now it comes in the form of an 'sdec' (sound decompressor) and an 'eat
>' (movie import). So far, I didn't have a need for a  media handler. Do you
>think I'll need one for additional functionality?

I would hope not. MP3 didn't need one.

>
>>>  The last thing which I haven't figured out yet, when used in OS X on my
>>>  iBook, it skips at frequent yet consistent intervals. Almost sounds as
>>>  though carbonizing it changed the physical bit-size of one of my variables
>  >> (ie. One byte being perceived as 16 bits or something like this)...

This is possible - you need to be careful about the packing you 
specify in your headers. The QT headers have big ugly macro blobs at 
each end to make the old structures that have short long short type 
stuff not get padded out to longs by the X compilers. Declaring 
copies of QtT structures in your own headers can make this happen.

At 2:20 AM +0200 7/24/01, Segher Boessenkool wrote:
>
>It wouldn't need the trickery if it would be possible to let the importer
>"export" packets (i.s.o. pages), but that would mean i'd have to use a
>media that's not associated with the original file, and that would mean
>much worse performance.

Not sure I follow this. Import in place is a good idea from a 
usability point of view. The trick with SampleDescriptionExtensions 
is that the are in the Movie Header

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