sön 2019-04-28 klockan 22:17 +0200 skrev Marton Balint:
>
> On Sun, 14 Apr 2019, Tomas Härdin wrote:
>
> > fre 2019-04-12 klockan 01:09 +0200 skrev Marton Balint:
> > > KLV length is BER encoded (variable size), but the code assumed the
> > > encoding to
> > > always use 4 bytes.
> > >
> > > Fixes parsing Random Index Pack in
> > > samples/MXF/issue2160/PW0805A0V01.4C5B5636.EFA330.mxf.
> > >
> > > > Signed-off-by: Marton Balint <c...@passwd.hu>
> > >
> > > ---
> > > libavformat/mxfdec.c | 7 +++++--
> > > 1 file changed, 5 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> > > index 6f0f87763d..a69f2f1996 100644
> > > --- a/libavformat/mxfdec.c
> > > +++ b/libavformat/mxfdec.c
> > > @@ -3126,9 +3126,12 @@ static void
> > > mxf_read_random_index_pack(AVFormatContext *s)
> > > goto end;
> > > avio_seek(s->pb, file_size - length, SEEK_SET);
> > > if (klv_read_packet(&klv, s->pb) < 0 ||
> > > - !IS_KLV_KEY(klv.key, mxf_random_index_pack_key) ||
> > > - klv.length != length - 20)
> > > + !IS_KLV_KEY(klv.key, mxf_random_index_pack_key))
> > > goto end;
> > > + if (klv.next_klv != file_size || klv.length <= 4 || (klv.length - 4)
> > > % 12) {
> > > + av_log(s, AV_LOG_WARNING, "Invalid RIP KLV length\n");
> > > + goto end;
> > > + }
> >
> > Looks OK.
>
> Thanks, applied.
>
> >
> > Aside: Looking at klv_read_packet(), I'm suspicious of its use of
> > mxf_read_sync(). That feels like something that only belongs in
> > mxf_read_header(), to deal with run-in. Baptiste added it in
> > cabe2527ef3. FATE passes without it.
>
> I wonder if it is there to allow some byte based seeking or handle damaged
> files more gracefully? I agree it is strange a bit, maybe Baptise can chip
> in...
I *suspect* it has something to do with seeking in frame wrapped files
with crappy or non-existing indexes. But then it would be best if it
were used only in mxf_read_seek()
/Tomas
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