[vorbis-dev] Problems compiling Mac Libs

Kevin Marks kmarks at apple.com
Tue Apr 17 10:55:52 PDT 2001

At 10:22 pm -0500 16/4/01, Steve Nicolai wrote:
>on 4/16/01 4:11 PM, Nick D'Amato at nick at nouturn.com wrote:
>>  I then built the sample encoder and included the libs. I tried to encode a
>>  file and BOOM! Frozen Mac!
>I've seen this with the release builds of the libraries.  I'm using the
>debug versions which seem to work fine.  I've not taken the time to track
>it down, it's on my TODO list though.

Can you get into Macsbug when it freezes? Is the heap corrupt? Are 
you allocating memory at interrupt time? Does turning on heap 
scrambling make it crash sooner?

If its a threading issue, you may find it easier to catch on X.

>  > Any suggestions? I'm dying to get this thing working, it looks great! I'm
>>  intersted in building a free vorbis codec for Quicktime if I can get these
>>  libs going.
>I've got an export component that is nearly feature complete, and I'm
>working on the sound compression component, but lacking some info on vbr
>sound compression components.

There isn't currently a way to make a VBR sound compression component 
in QuickTime. Existing ones (such as PureVoice) work by padding to 
the maximum length for a block, and then have the extra bytes 
stripped off by the packetizer before streaming or by the exporter 
before writing the output file. I'm not sure how amenable Vorbis is 
to this approach.

If you put the codebooks in a SampleDescriptionExtension, you should 
have a sensible upper bound on the packet length. There is brief 
discussion of truncating packets to fit a bitrate on the Vorbis 
website, but I don't know if this has been tried.

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