[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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