[Theora-dev] Encoding theora...

illiminable ogg
Tue Jun 29 11:00:48 PDT 2004

Just trying to debug my theora encoder... just wondering if someone could
give me some insight on a few thigns...

In the yuv_buffer i'm sending in... i am just setting

y_stride = y_width = videoWidth
uv_stride = videoWidth/2
y_height = videoHeight
uv_height = videoHeight/2

Making the y buffer (width*height) and each of u and v (width*height/4)

Am i correct in doing this ? I knwo stride needn't equal width... but from
the videos width, can i just make them equal ? Any restrictions ?

Also the other encoding parameters... i am just using the default values
shown in the encoder example...

For the bitrate fields... what happens if i set it to 0 ? Will it do some
default action ?

Also the aspect ratio fields... i am just setting

aspect_numerator = videoWidth
aspect_denominator = videoHeight

Am i correct in doing this ? Any restrictions ?

Also... i'm noticing that most of the filters in directshow output YUY2 and
not YUV12... just curious if there is code floating around somewhere to do
the conversion before i write it myself... it doesn't look too complex

Also, looking at some wmv output... (which is a format that outputs YV12)...
it doesn't set a frame rate in the setup header... so i assume this means
it's a variable frame rate if such a thing exists ?? Any thoughts on the
best way to map a variable frame rate output onto theoras fixed frame rate ?



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