[FFmpeg-devel] [PATCH] lavf/mpl2dec: skip BOM

[wm4]

On Fri, 15 Apr 2016 15:01:23 +0200
Clément Bœsch <u at pkh.me> wrote:

> On Fri, Apr 15, 2016 at 02:58:00PM +0200, wm4 wrote:
> > Stolen from microdvddec.c.
> > 
> > Fixes ticket #5442.
> > ---
> >  libavformat/mpl2dec.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/libavformat/mpl2dec.c b/libavformat/mpl2dec.c
> > index 59589d5..2a0cb28 100644
> > --- a/libavformat/mpl2dec.c
> > +++ b/libavformat/mpl2dec.c
> > @@ -26,6 +26,7 @@
> >  #include "avformat.h"
> >  #include "internal.h"
> >  #include "subtitles.h"
> > +#include "libavutil/intreadwrite.h"
> >  
> >  typedef struct {
> >      FFDemuxSubtitlesQueue q;
> > @@ -39,6 +40,9 @@ static int mpl2_probe(AVProbeData *p)
> >      const unsigned char *ptr = p->buf;
> >      const unsigned char *ptr_end = ptr + p->buf_size;
> >  
> > +    if (AV_RB24(ptr) == 0xEFBBBF)
> > +        ptr += 3;  /* skip UTF-8 BOM */
> > +
> >      for (i = 0; i < 2; i++) {
> >          if (sscanf(ptr, "[%"SCNd64"][%"SCNd64"]%c", &start, &end, &c) != 3 &&
> >              sscanf(ptr, "[%"SCNd64"][]%c",          &start,       &c) != 2)  
> 
> make sure you don't need it in the read_header() callback too.
> 
> BTW, as a side note, it will be appropriate to s/if/while/, I have a few
> samples with more than one bom... IIRC only in ASS files but we probably
> to have it uniformly across sub text decoder. It's fine to keep it
> consistent with a single if for now.
> 
> thanks
> 

Indeed the BOM causes dropping the first subtitle event in
read_header().