[theora] Theora encoder performance

Mircea Gliga mgliga at integrasoft.ro
Mon Dec 7 06:06:15 PST 2009

I'm evaluating some video codecs for a online conference system. I'm 
encoding images (640x480)
from a webcam. I've been playing around with theora and xvid.
    First of all, using theora, the decoded image looks strange: 
On the left side the image from the webcam, on the right side the image 
from the
webcam encoded, and then decoded using theora. As you can see there are 
some strange
colors overs there ( looks like edge detection  :-D ).
    Then I measured how long does it take for Theora to encode an image 
(/th_encode_ycbcr_in/ and /
th_encode_packetout/ calls).

    int TIMER_t0 = GetTickCount();
    int ret = th_encode_ycbcr_in( (th_enc_ctx*)m_encoderHandler, ycbcr);
    ogg_packet    op;
    int TIMER_t1 = GetTickCount();
    printf( "Timer : %d \n",TIMER_t1 - TIMER_t0 );

    On average: *80 ms*.
    Using XVID I've obtained between *20-25 ms* for an image. That's 
60ms longer using Theora.
    I don't know if I am doing something wrong while initializing the 
encoder, or that's the way it
supposed to be. The encoder initialization used by me can be found here: 
    Used hardware/software:
    Processor    Pentium(R) Dual-Core  CPU      E5200  @ 2.50GHz, 2400 
Mhz, 2 Core(s), 2 Logical Processor(s)
    Installed Physical Memory (RAM)    2.00 GB
    OS Name    Microsoft® Windows Vista^(TM)

Any ideas or suggestions are welcomed.

Mircea Gliga

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