[FFmpeg-devel] avformat/lrcdec: fix losing opening bracket

[Umair Khan]

On Sat, Jul 14, 2018 at 8:37 PM Michael Niedermayer
<michael at niedermayer.cc> wrote:
>
> On Fri, Jul 13, 2018 at 01:34:47PM +0530, Umair Khan wrote:
> > On Wed, Jul 11, 2018 at 11:07 PM Michael Niedermayer
> > <michael at niedermayer.cc> wrote:
> > >
> > > On Tue, Jul 10, 2018 at 08:10:00PM +0530, Umair Khan wrote:
> > > > Hi,
> > > >
> > > > Patch attached.
> > > >
> > > > -Umair
> > >
> > > >  lrcdec.c |    3 +++
> > > >  1 file changed, 3 insertions(+)
> > > > 6782b07bfa45139361c15527ee5fb78e5893b9ba  0001-avformat-lrcdec-fix-losing-opening-bracket.patch
> > > > From 95a5d2e5575c5f895e4251775a48f7deb4c86124 Mon Sep 17 00:00:00 2001
> > > > From: Umair Khan <omerjerk at gmail.com>
> > > > Date: Tue, 10 Jul 2018 19:51:41 +0530
> > > > Subject: [PATCH 1/1] avformat/lrcdec: fix losing opening bracket
> > > >
> > > > Fixes #7255
> > > >
> > > > Signed-off-by: Umair Khan <omerjerk at gmail.com>
> > > > ---
> > > >  libavformat/lrcdec.c | 3 +++
> > > >  1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/libavformat/lrcdec.c b/libavformat/lrcdec.c
> > > > index f4e9a4efa9..d1e28aff87 100644
> > > > --- a/libavformat/lrcdec.c
> > > > +++ b/libavformat/lrcdec.c
> > > > @@ -68,6 +68,9 @@ static int64_t count_ts(const char *p)
> > > >                   (p[offset] >= '0' && p[offset] <= '9'))) {
> > > >              offset++;
> > > >          } else {
> > > > +            if (in_brackets) {
> > > > +                --offset;
> > > > +            }
> > > >              break;
> > >
> > > this is probably ok but it doesnt fix this completely
> > >
> > > consider 2 [[
> > > or a [123
> > >
> > > The code should probably remember the last position after a correctly
> > > parsed timestamp or maybe use sscanf() to parse these timestamps
> >
> > The new attached patch takes care of these cases.
> >
> > > Also it seems the code doesnt handle timestamps in the middle of lines
> > > (not related to your patch though)
> >
> > I can handle this case if you can give me an example of what case you
> > are talking about exactly.
> >
> > -Umair
>
> >  lrcdec.c |    7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 72feffd56541236991001caaa92e533382b98b53  0001-avformat-lrcdec-fix-losing-opening-bracket.patch
> > From 81c2e13aa0a7559886502cfb69f788bd0de7a64a Mon Sep 17 00:00:00 2001
> > From: Umair Khan <omerjerk at gmail.com>
> > Date: Fri, 13 Jul 2018 13:24:51 +0530
> > Subject: [PATCH 1/1] avformat/lrcdec: fix losing opening bracket
> >
> > ---
> >  libavformat/lrcdec.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/libavformat/lrcdec.c b/libavformat/lrcdec.c
> > index f4e9a4efa9..4093cbdf10 100644
> > --- a/libavformat/lrcdec.c
> > +++ b/libavformat/lrcdec.c
> > @@ -60,14 +60,15 @@ static int64_t count_ts(const char *p)
> >          } else if(p[offset] == '[') {
> >              offset++;
> >              in_brackets++;
> > -        } else if (p[offset] == ']' && in_brackets) {
> > -            offset++;
> > -            in_brackets--;
> >          } else if(in_brackets &&
> >                   (p[offset] == ':' || p[offset] == '.' || p[offset] == '-' ||
> >                   (p[offset] >= '0' && p[offset] <= '9'))) {
> >              offset++;
> >          } else {
> > +            if (p[offset] == ']' && in_brackets) {
> > +                offset++;
> > +                in_brackets--;
> > +            }
> >              break;
>
> This breaks multiple times like:
> [00:35.62][00:35.63][00:35.64][[[[123 is a number
>
> this should be interpreted as 3 occurances of "[[[[123 is a number" IIUC

Are you sure about this? As much as I read, there's no example of it
being interpreted as 3 occurrences. It could be interpreted as empty
words at the first two timestamps.

For timestamps in the middle of the lines, do you mean something like
- "[xx.yy.zz] line1 [xx.yy.zz] lines2" ? Or something else?

-Umair