[Theora-dev] Directshow filters 0.64.7878

illiminable ogg at illiminable.com
Sat Oct 2 11:15:41 PDT 2004


>Great. And I still have some more questions to ask :-)
>I queried the encoder filter for the ITheoraEncodeSettings interface. These
>are the default values:

That's definately looking like random memory to me :) That should be easy to 
fix.

>However, the video bitrate still fluctuates from around 8 KB/s up to 45 
>KB/s.
>I guess this is your hardcoded bitrate 400000 bps, so maybe the interface
>doesn't propagate the values to the encoder at all?

It should do, because the filters use that interface... however what it most 
likely is, is because the encoder settings get  finalised at the time the 
filter connects, if the filter is already connected, those settings won't be 
loaded into the actual encoder. I'll do something about that when i get the 
chance. In the meantime, if you set the settings on the encoder before you 
connect it up, it should work.

>I noticed that black frames (webcam lens shut) produce 45 KB/s, while 
>moving
>video is around 8-20 KB/s. How can that be? Is the encoder fooled by the
>background noise the webcam produces?

Sounds feasible ! One of the theora devs would know more about it than me :)

>Maybe it has to do with the quality
>setting, though I don't know what it's for and what 13 means to it.

I'm not sure where 13 came from ! It should default to 30 ! I don't know 
exactly what it means just that it's some abstract representation of quality 
similar to vorbis... though it wouldn't make sense to set the quality really 
high and the bitrate really low, it will still accept those settings, so 
some trial and error or finding good settings other people use would be 
useful for you.

There's actually about 20 more settings that aren't exposed on that 
interface... i'll get to that at some point too, i suppose it wouldn't hurt 
to make them all available on the interface, even if they don't appear in 
the filter properties yet.

Cheers,

Zen.



----- Original Message ----- 
From: "Robert Huitl" <theora-dev at huitl.de>
To: <theora-dev at xiph.org>
Sent: Saturday, October 02, 2004 12:55 AM
Subject: Re: [Theora-dev] Directshow filters 0.64.7878


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