[Theora-dev] using theora
jkintree at swbell.net
Sun Sep 12 13:30:59 PDT 2004
Having built libtheora-1.0alpha3, I tried it out on a 46 second long,
161 MByte raw dv format video clip.
First, I copied these lines from ogg-theora-microhowto.html
mplayer -ao pcm -aofile stream.wav -vo null file_to_be_encoded.avi &
mplayer -vo yuv4mpeg -ao null -nosound file_to_be_encoded.avi &
encoder_example -v 1 -a 1 stream.wav stream.yuv > theora_file.ogg
into a file named "encode", substituted "file_to_be_encoded" and "theora_file"
with my own filenames, and gave "encode" execute permission.
It took about 15 minutes to encode my dv format clip, the resulting .ogg file
was 6.8 MBytes, and when I played it with mplayer, the audio sounded good,
but the video looked more like a slide show.
When I used MainActor to encode that same dv format clip into mpeg2 format, it
took about 2 minutes and 50 seconds, the resulting file was 25.3 MBytes, and
both the audio and video were close to the quality of the dv format file.
When I used MainActor to encode that same dv format clip into mpeg1 format, it
took about 2 minutes and 20 seconds, the resulting file was 10.9 MBytes, and
the audio was good while the video has not as sharp as the mpeg2 version.
I've got a 750 MHz AMD Duron with 128 MBytes of RAM. There was a message when
running encode that said compiling mplayer without CPU detection was a
What might I try to get ogg theora output that looks at least as good as mpeg1
instead of like a slide show? Will optimizations reduce the encoding time
from 15 minutes to less than three minutes?
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