Steve R. Bennen wrote:
I've been Googling questions in order to understand some basic parameter settings and I haven't been able to find a clear answer. (Actually, some more advanced settings make sense to me thanks to the link provided by Stefano Sabatini http://thread.gmane.org/gmane.comp.video.ffmpeg.user/16235/focus=16283 ) I am deciding between a few different scenarios. My problems are as follows. With a Player screen size at 576 x 432, which is 4:3, I will have source video uploaded in different aspect ratios.
1. If I use -s 576x432 will that force it? What will happen if I use the -s but I don't use the -aspect parameter? 2. If I use -aspect 4:3, what will happen to a source video file with a 16:9 aspect ratio? Will it automatically scale to 576 x 324 (16:9) because 576 is the defining dimension? 3. What if I want the screen size to be 576 x 432, regardless of the source aspect ratio, but I want both 16:9 and 4:3 sizes to fully fit in the 4:3 screen. Do I cropleft and cropright for the 16:9, but leave the 4:3? I want the ouput to show the "middle" of 16:9 and the 4:3. Can both be done?
From my understanding, the -aspect command line option only sets a flag in some containers (mpeg for sure, possibly others), whose end result is to stretch the video when it's being viewed to a given aspect ratio.
The -s option specifies the size of the video frames, and it ignores aspect ratios of the source video and the -aspect option. You'll have to calculate the video size beforehand and pass the exact value to -s. Concerning the -aspect flag, unless you are sure your container format supports is properly, I'd recommend not using it (that is, using a 1:1 aspect ratio) and resizing the video to a proper size, possibly adding black bars with -padtop and -padbottom. You'll have to calculate the size of the video and the bars manually, however. -- ''', o_)O \)____)" \_ ) woof! '',,,,,, || || "--'"--' Eduardo M KALINOWSKI eduardo at kalinowski.com.br http://move.to/hpkb