[FFmpeg-devel] [vf_ass.c] 2 lines of code that need your attention

Stefano Sabatini stefasab at gmail.com
Mon Mar 19 19:43:09 CET 2012

On date Friday 2012-03-16 10:03:29 +0800, REN Lifeng encoded:
> Hi developer of the ASS/SSA video filter,


> 2. aspec ratiot of video  v.s. aspect ratio of display
> 146:    ass_set_aspect_ratio(ass->renderer, dar, sar);
>  * \param dar display aspect ratio (DAR), prescaled for output PAR
> I has a Karaoke vedio with size of 640x272 and a subtitle in ASS format.
> With line 146, there are cases where multiple words changes color
> simultaneously. This should not happen. And this problem will not arise
> if we play the video and subtitle with Mplayer. And it will not arise if
> we remove line 146 from vf_ass.c.
> To provide more details, I also the following comparation. With
> attatched subtitle, test1 generate 22 images among which only one
> Chinese character is split. test2 generate 23 images where 2 characters
> are split. You may need some Chinese fonts to reproduce the problem.

Check attached patch and tell me if it works for you. The simple
solution is to simply set the dar to 1.0, but since we like nifty
switches and buttons, it is making it configurable.
FFmpeg = Fundamentalist and Fabulous Meaningful Pitiful Enlightened Goblin
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