[MEncoder-users] Trying to cut at exact frames (-hr-edl-seek etc.)

[Thorsten Pferdekämper]

On Friday 20 May 2005 07:09, Oded Shimon wrote:
> On Thu, May 19, 2005 at 08:55:02PM +0200, Thorsten Pferdek?mper wrote:
> > Hi,
> > [...]
> > Let d be the duration of one frame (i.e. 1/framerate).
> > Let [a,b] be the frame interval you want to keep. (Starting to count with
> > 0) Let l be something bigger than the length of the video in seconds Then
> > you need two entries in the EDL file:
> > 	0.00		a*d	0
> > 	b*d		l	0
> >
> > At least, this works if b is really bigger than a. with a=b, it does not
> > work. I would have expected, that I will get exactly one frame in this
> > case, but I get zero frames. With b = a+1, I get two frames (a and b).
> > So, what does this mean? It simply means that it is impossible to cut out
> > exactly one frame (or every second frame or something like that). Perhaps
> > this is not very important and rather academic, but I thought it was
> > worth to be mentioned.
>
> Just a hunch, try 'b = a+0.5'. With 'a = b' You get an error before the
> encode even starts i assume?
>
Hi,
ok, I did some further tests. I believe that you get 2 frames whenever 
	a < b <= a+1
Here are my test examples: 

1. Without any edl: 1933 frames

2. Using the following edl 
	0	4		0
	4	9999	0
produces a message because of overlapping intervals. It seems that mencoder 
ignores the second line. It skips the first 4 seconds. The output has 1833 
frames. (Btw: frame rate is 25, a=100. This makes the "4".)

3. Using the edl you suggested:
	0	4	 0
	4.02	9999 0
There is no error message, but it creates 2 frames.

4. The same as 3. with 
	0	4		0
	4.04	9999	0		

Regards,
	Thorsten