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How does any video codec get the its input frame?

Started by tommy June 2, 2006
I am beginner studying the  videco codec.
So I am sorry in case of I may have stupid question.
On my way to study the H.263 video coder, I have question how encoder
processes the frame from A/D converter.
I imagine like that.
After raw image signal(R,G,B) from A/D converter, color mapping is
performed.( convert RBG to YCbCr) one frame store the buffer and then
it is encoded.
Simultaneously, next frame is stored in next buffer area. How many
frame is stored to process it as the real time? 2  or 3 frame?
Also, Where I get the such information ( processing method,  popular
video A/D converter)?

Thanks in advance

tommy wrote:
> I am beginner studying the videco codec. > So I am sorry in case of I may have stupid question. > On my way to study the H.263 video coder, I have question how encoder > processes the frame from A/D converter. > I imagine like that. > After raw image signal(R,G,B) from A/D converter, color mapping is > performed.( convert RBG to YCbCr) one frame store the buffer and then > it is encoded. > Simultaneously, next frame is stored in next buffer area. How many > frame is stored to process it as the real time? 2 or 3 frame?
That's a matter of on-going debate and a function of several variables. Consider that, even though your average rate is the frame rate, the instantaneous rate may vary quite a bit due to, e.g., complexity in encoding a specific frame. Depending on this, you may need to buffer 2, 3 or even more frames.
> Also, Where I get the such information ( processing method, popular > video A/D converter)?
Two popular video A/Ds are the TI 5150 and Phillips SAA 7115. They are called "video decoders" in video processing vernacular. Try searching TI's website for the DM642 processor, which is their star product (or was) for performing video processing. They should have lots of app notes on this topic. --Randy Yates