[FFmpeg-devel] DVB Subtitles - "Hard Subtitles"
stefano.sabatini-lala at poste.it
Tue Apr 19 00:55:07 CEST 2011
On date Monday 2011-04-18 23:08:32 +0100, JULIAN GARDNER encoded:
> > > ffmpeg -i test.ts -vf drawbox:10:10:710:100:red -f
> > mpegts -y a.ts
> > >
> > > Works as it should
> > >
> > > ffmpeg -i test.ts -vf drawbox:10:10:710:100:red -s
> > 352x288 -f mpegts -y a.ts
> > >
> > > Works but the box is drawn off screen, so my question
> > is
> > >
> > > 1. How do i get the filter to work BEFORE the resize?
> > is there a filter that does this?
> > -s WxH will cause ffmpeg to apply a scale filter *at the
> > begin* of the
> > filterchain, so before the drawbox filter is applied.
> > So what you want is:
> > -vf drawbox:10:10:710:100:red,scale=352:288
> > and you don't have to specify the -s option.
> > BTW this list is for FFmpeg development, user questions
> > should be
> > posted to ffmpeg-user.
> So the fact that i am trying to develop code, the -devel list is not
> applicable but the -user list is? dont understand the logic.
The fact that you're developing FFmpeg code was not clear from your
question, indeed it appeared like an user question.
> As i said before i am trying to draw on the raw video frame BEFORE
> scaling as i want to keep the subtitles int the correct position and
> size, and I dont want to have to scale the subtitles before drawing
> onto the screen, seems silly to have 2 scalings going on.
I believe I addressed your question, that is avoid the ffmpeg -s
option because it will cause non-completely predictable results.
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