Hi,
On Tue, Aug 4, 2015 at 12:42 PM, Hendrik Leppkes <h.lepp...@gmail.com>
wrote:
> On Mon, Aug 3, 2015 at 9:54 PM, Hendrik Leppkes <h.lepp...@gmail.com>
> wrote:
> > On Mon, Aug 3, 2015 at 9:30 PM, Nicolas George <geo...@nsup.org> wrote:
> >> Le sextidi 16 thermidor, an CCXXIII, Michael Niedermayer a écrit :
> >>> i also found this comment in a patch in my inbox:
> >>>
> >>> + /* When using Standard C input functions, also check if there
> >>> + is anything in the buffer. After a call to such functions,
> >>> + the input waiting in the pipe will be copied to the buffer,
> >>> + and the call to PeekNamedPipe can indicate no input available.
> >>> + Setting stdin to unbuffered was not enough, IIRC */
> >>> + if (stdin->_cnt > 0)
> >>> + {
> >>> + char ch;
> >>> + //Read it
> >>> + read(0, &ch, 1);
> >>> + return ch;
> >>> + }
> >>>
> >>> This seems to explain what the code was intended to do
> >>
> >> That was my guess.
> >>
> >> This is ugly, and should be removed anyways. It is not possible to mix
> stdio
> >> and low-level reading like that, period.
> >>
> >> Fortunately, ffmpeg.c only uses stdin at one single place, a few lines
> below
> >> the corresponding code:
> >>
> >> }else
> >> if(scanf("%d", &debug)!=1)
> >> fprintf(stderr,"error parsing debug value\n");
> >>
> >> It needs to be changed to read a line with the low-level function
> >> (read_key()), exactly like 40 above for the 'c' case. I can not brew a
> patch
> >> right now, sorry.
> >>
> >> I suspect this would not work:
> >>
> >> printf 'd42\nC ... fontfile ...\n' | ffmpeg ...
> >>
> >> because the C will end up in the stdio buffer.
> >>
> >>
> >
> > Good catch. This command doesn't work with or without the hunk this
> > patch removes however.
> > A simpler command without drawtext would be:
> >
> > printf 'd0\n?' | ffmpeg -i ...
> >
> > If you see help output, it works. Using another command instead of d0
> > works fine, like a C command followed by a \n?
> > It also doesn't work on Linux, so thats a more fundamental problem.
> >
> > Since this fixes a build failure, unless we can find a use-case where
> > this hunk actually does make a difference, I would still rather remove
> > it.
> > If it causes any regression in the future, which we didn't think of
> > now, I'll be here to work on a fix.
> >
>
> Any further thoughts on this?
>
> I would love start setting up a VS2015 FATE box etc, once compilation
> actually works.
I thought the conclusion was to apply it? I certainly support that.
Ronald
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