On Wed, 1 Feb 2017 14:17:19 +0100
Paul B Mahol <one...@gmail.com> wrote:
> On 2/1/17, wm4 <nfx...@googlemail.com> wrote:
> > On Wed, 1 Feb 2017 13:31:46 +0100
> > Robert Krueger <krueger@lesspain.software> wrote:
> >
> >> On Wed, Feb 1, 2017 at 1:07 PM, wm4 <nfx...@googlemail.com> wrote:
> >>
> >> > On Wed, 1 Feb 2017 12:50:51 +0100
> >> > Paul B Mahol <one...@gmail.com> wrote:
> >> >
> >> > > Signed-off-by: Paul B Mahol <one...@gmail.com>
> >> > > ---
> >> > > libavformat/mov.c | 25 +++++++++++++++++++++++++
> >> > > 1 file changed, 25 insertions(+)
> >> > >
> >> > > diff --git a/libavformat/mov.c b/libavformat/mov.c
> >> > > index 9ae4f8c..75e1c9c60 100644
> >> > > --- a/libavformat/mov.c
> >> > > +++ b/libavformat/mov.c
> >> > > @@ -3764,6 +3764,25 @@ static int mov_read_keys(MOVContext *c,
> >> > AVIOContext *pb, MOVAtom atom)
> >> > > return 0;
> >> > > }
> >> > >
> >> > > +static int mov_read_xml(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> >> > > +{
> >> > > + uint8_t *xml;
> >> > > +
> >> > > + if (atom.size < 5)
> >> > > + return 0;
> >> > > +
> >> > > + avio_skip(pb, 4);
> >> > > + xml = av_calloc(atom.size - 4 + 1, sizeof(uint8_t));
> >> > > + if (!xml)
> >> > > + return AVERROR(ENOMEM);
> >> > > +
> >> > > + avio_read(pb, xml, atom.size - 4);
> >> > > + av_dict_set(&c->fc->metadata, "xml", xml, 0);
> >> > > + av_free(xml);
> >> > > +
> >> > > + return 0;
> >> > > +}
> >> > > +
> >> > > static int mov_read_custom(MOVContext *c, AVIOContext *pb, MOVAtom
> >> > > atom)
> >> > > {
> >> > > int64_t end = avio_tell(pb) + atom.size;
> >> > > @@ -5280,6 +5299,12 @@ static int mov_read_default(MOVContext *c,
> >> > AVIOContext *pb, MOVAtom atom)
> >> > > parse = mov_read_keys;
> >> > > }
> >> > >
> >> > > + if (!parse &&
> >> > > + atom.type == MKTAG('m','e','t','a') &&
> >> > > + a.type == MKTAG('x','m','l',' ')) {
> >> > > + parse = mov_read_xml;
> >> > > + }
> >> > > +
> >> > > if (!parse) { /* skip leaf atoms data */
> >> > > avio_skip(pb, a.size);
> >> > > } else {
> >> >
> >> > We had this discussion recently: the metadata AVDictionary should
> >> > probably only contain real tags, not other information that's contained
> >> > in the format but for which libavformat has no good way to export yet.
> >> >
> >> > There needs to be a concept for distinguishing user-visible tags and
> >> > other data.
> >> >
> >> > (You don't want to show a xml dump in a GUI that happens to use ffmpeg,
> >> > do you?)
> >> >
> >> >
> >> I thought that was already the case for XMP (i.e. xml) metadata embedded
> >> in
> >> mov. I must look up how that was handled. I seem to remember there was a
> >> flag to suppress this on the command line. With the policy you propose,
> >> libavformat will be of a lot less use for api users. Not that I had a vote
> >> here. It's just 2c of an api user.
> >
> > I'm not voting for removing it, just that there should be a separate
> > mechanism for this.
>
> Can you define/explain such thing in detail?
> If not I will use current approach.
Using side data. Or maybe just a different metadata field. Or clearly
defining which keys are internal and which are meant to be shown to the
user as text (as far as specified by the file format).
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