[ogg-dev] Xiph QT Theora Codec

Anders Kirchenbauer ack0954 at mac.com
Mon Dec 19 11:09:56 PST 2005

Taking a look ahead at your QT (OSX version) work, you have Theora  
Encoding and Decoding on the list.  This could be very beneficial as  
many times the only way to get a constant frame-rate out of QT is to  
export (and for DV video recorded in QT, this can be a large issue).   
Another major issue is that the video coming from DV (at least the  
sources I have used) is almost always interlaced, and since there is  
no deinterlace in the filter options (not to mention lack of a filter  
chain), but the codecs seem to be the best way to put a deinterlace  
into it prior to actual encoding of the frames.
Whether it is better to do this in an intermediary file or not is up  
to implementation.

I see by the current 0.1.3 sources that FLAC is probably next on the  
list, which makes Theora in the distance, but I thought I'd ask now.   
I have been generating Theora files using one of the CLI tools, a  
script file that calls mplayer for audio and dumps to a FIFO and  
calls it for YUV and dumps to FIFO then runs the Alpha 5 encoder on  
the FIFO files to generate a final OGG.  Due to the DV not going in  
at a constant 29.97, the audio desyncs, so I have to export the  
initial DV to another DV with a normalized FPS of 29.97.  When  
dealing with 10GB/hr of video, this process becomes large and  
unwieldy quickly.  I take that file and use the 2ogg.sh to encode it  
perfectly, but QT Theora would take it straight from the original  
source with less loss from intermediary transcodes.

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