[FFmpeg-devel] [PATCH] avcodec/mpeg12dec: parse A53 caption data embedded in SCTE-20 user data

Aman Gupta ffmpeg at tmm1.net
Wed Mar 15 21:10:35 EET 2017


On Sat, Mar 11, 2017 at 7:05 AM, Michael Niedermayer <michael at niedermayer.cc
> wrote:

> On Mon, Mar 06, 2017 at 10:23:14AM -0800, Aman Gupta wrote:
> > From: Aman Gupta <aman at tmm1.net>
> >
> > ---
> >  libavcodec/mpeg12dec.c | 38 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 38 insertions(+)
> >
> > diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
> > index 27db14c..8cafdb0 100644
> > --- a/libavcodec/mpeg12dec.c
> > +++ b/libavcodec/mpeg12dec.c
> > @@ -2260,6 +2260,44 @@ static int mpeg_decode_a53_cc(AVCodecContext
> *avctx,
> >              avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
> >          }
> >          return 1;
> > +    } else if (buf_size >= 2 &&
> > +               p[0] == 0x03 && (p[1]&0x7f) == 0x01) {
> > +        /* extract SCTE-20 CC data */
> > +        GetBitContext gb;
> > +        int cc_count = 0;
> > +        int i;
> > +
> > +        init_get_bits(&gb, p + 2, buf_size - 2);
> > +        cc_count = get_bits(&gb, 5);
> > +        if (cc_count > 0) {
> > +            av_freep(&s1->a53_caption);
> > +            s1->a53_caption_size = cc_count * 3;
> > +            s1->a53_caption      = av_malloc(s1->a53_caption_size);
> > +            if (s1->a53_caption) {
>
> a53_caption_size should be reset to 0 if allocation fails to keep the
> fields consistent
>

The other branches in this function all follow the same pattern, and will
not reset a53_caption_size on malloc failure.

Would you like me to fix all of them?


>
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> In fact, the RIAA has been known to suggest that students drop out
> of college or go to community college in order to be able to afford
> settlements. -- The RIAA
>
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