On Fri, 12 Jun 2015 00:11:24 +0530 Niklesh Lalwani <niklesh.lalw...@iitb.ac.in> wrote:
> Ok so it goes like this. > > We first find out the height and width of the video stream from the > header box. The dimensions of the text track (subtitle track) is then > set (in pixels). Here, we have used the width equal to the width of > the video, and height equal to 1/10 of the video height. > The write matrix specifies the coordinate origin and the translation > values from the origin, ie, where to place the subtitle track. Here, > we have set tx = 0; and ty = 9/10 of the video track height. > There is also a text box inside this subtitle area, inside which the > text is rendered. For now, this is set equal to the the subtitle track > dimensions. > > Philip, please correct me if I am wrong. Nicolas was asking about the general mechanism, I think. So, the subtitle track has dimensions, just like the video track, and for a given set of dimensions, it can be placed at a position within the video track's dimensions. In Nikleh's example, it's the same width, and 1/10 of the height, and placed 9/10'th down, so as to occupy the bottom 1/10 of the display area. Within the subtitle area, specific subtitles occupy text boxes that can be smaller than the full area. In our simple example, all subtitles are in the same box that occupies the full area. --phil _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
