[mythtv] ffmpeg SWSCALE!

Yeasah Pell yeasah at schwide.com
Thu Aug 31 04:00:59 UTC 2006

Michael T. Dean wrote:
> On 08/30/06 22:25, Yeasah Pell wrote:
>> the question I was addressing is simply "do I need a greater resolution 
>> discrete output device than my source signal in order to get the best 
>> image possible from the source", not "is my CRT better than your LCD" or 
>> anything else related to the specifics of any display device.
>> The answer I came up with is "if you have a properly set up viewing 
>> distance given your eyes and the size of the display device, you do not."
> But remember that video is a sequence of images--each of which is 
> reconstructed separately.  Therefore, aliasing in one image may not be 
> exactly the same as aliasing in the following image (and the next and 
> ...).  This results in "flicker" (as in flickering pixels), which is 
> definitely noticeable--even with your eyeball filters.  :)  Therefore, 
> reducing aliasing is still important--even at HDTV resolutions.
Mmmm. Interesting. You just had to go and kick it up one dimension, 
didn't you? :-) I can certainly buy this explanation, though I'm having 
difficulty visualizing the magnitude of it as a viewer. Intuitively it 
seems like if it's primarily a temporal problem, a temporal filter would 
be a reasonable solution -- but I'm well aware of the difficulties in 
temporally filtering moving video (witness the complexity of good 

> (And this flicker doesn't even require geometric aliasing--i.e. an 
> object whose size is small enough that it falls between samples in the 
> image, and appears/disappears/reappears in different frames.  So, it can 
> occur in a series of images whose resolutions are appropriate for the 
> content represented therein.)
Right, aliasing of that nature won't be helped by scaling up the image 
anyway -- anything of that nature is a theoretically a source problem.

More information about the mythtv-dev mailing list