Relation between Frames per second amd MCPS for a Video Encoder & Decoder

Hello,
       I am trying to find relation between frames per second(fps),
Clock rate (Cycles/sec) and MCPS(Million cycles per second) for the
video encoder.

1.) For an Video encoder How can i calculate the MCPS consumed. Is fps
needed for this calculation, if yes, how can one get fps?

2.) For a Video decoder - How is MCPS calculated , how is fps
calculated?


Thank You.
Regards,
-AD.

goldenmean wrote:
> Hello,
>        I am trying to find relation between frames per second(fps),
> Clock rate (Cycles/sec) and MCPS(Million cycles per second) for the
> video encoder.
> 
> 1.) For an Video encoder How can i calculate the MCPS consumed. Is fps
> needed for this calculation, if yes, how can one get fps?
> 
> 2.) For a Video decoder - How is MCPS calculated , how is fps
> calculated?

It takes (on the average) some number of cycles to decode a frame. How 
many depends on the decoder. (cycles/frame)*(frames/sec) = cycles/sec 
Why is that a mystery?

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

goldenmean wrote:
> Hello,
>       I am trying to find relation between frames per second(fps),
> Clock rate (Cycles/sec) and MCPS(Million cycles per second) for the
> video encoder.
>
> 1.) For an Video encoder How can i calculate the MCPS consumed. Is fps
> needed for this calculation, if yes, how can one get fps?
>
> 2.) For a Video decoder - How is MCPS calculated , how is fps
> calculated?
>

Frames per second is generally a given and not calculated.  Certainly this 
is true for the input or source of the video unless it is synthesized / 
computed video. I'll call this the native input frame rate.

If processing video and you are compute bound then you could generate a 
frame rate lower than the native frame rate.

If you must output a particular frame rate then there can be a mismatch 
between the input frame rate and the output frame rate.  I'll call this 
output the native output frame rate.  This is common when converting from 
NTSC video to computer video, etc. etc.

If the input and output frame rates are different then you will (as a matter 
of physics) either have frame dropping or frame repetition at the output. 
There is really no way around it beyond filtering of some types.

For MCPS you need to know a lot and then you can only estimate within 
reason.  A couple of simple ways about it would be:

1) Calculate the number of processor operations per output frame.  If some 
operations take more than a single compute cycle, then you have to take this 
into account.
Multiply the number of operations per frame by the output frame rate - 
which, as above, you must decide.  This gives the compute cycles per second.

2) I the processor won't handle the output frame rate you desire, then 
reduce the output frame rate until it does.  Use the same process as in (1) 
but adjust the output frame rate until the number of operations per second 
is adequately low for the processor.

Estimating the wall clock time it takes to process a frame can be difficult 
if there are a lot of interrupts occurring, etc.  And, wall clock time is 
tied directly to achievable fps.

Fred