[FFmpeg-devel] [PATCH]lavf/mov: Export vendor metadata

[wm4]

On Thu, 26 Jan 2017 00:35:17 +0100
Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:

> 2017-01-26 0:19 GMT+01:00 Hendrik Leppkes <h.leppkes at gmail.com>:
> > On Thu, Jan 26, 2017 at 10:04 AM, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:  
> >> 2017-01-25 14:22 GMT+01:00 wm4 <nfxjfg at googlemail.com>:  
> >>> On Mon, 12 Dec 2016 12:12:37 +0100
> >>> Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> >>>  
> >>>> From 7c26220a8734fe7dc293efe6c13e3baf91defc7e Mon Sep 17 00:00:00 2001
> >>>> From: Carl Eugen Hoyos <cehoyos at ag.or.at>
> >>>> Date: Mon, 12 Dec 2016 12:07:27 +0100
> >>>> Subject: [PATCH 2/2] lavf/mov: Export vendor metadata.
> >>>>
> >>>> ---
> >>>>  libavformat/mov.c         |    5 ++++-
> >>>>  tests/ref/fate/mov-zombie |    2 +-
> >>>>  2 files changed, 5 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/libavformat/mov.c b/libavformat/mov.c
> >>>> index 0b1c182..a19ebbf 100644
> >>>> --- a/libavformat/mov.c
> >>>> +++ b/libavformat/mov.c
> >>>> @@ -1842,6 +1842,7 @@ static void mov_parse_stsd_video(MOVContext *c, AVIOContext *pb,
> >>>>                                   AVStream *st, MOVStreamContext *sc)
> >>>>  {
> >>>>      uint8_t codec_name[32] = { 0 };
> >>>> +    uint8_t vendor[5] = { 0 };
> >>>>      int64_t stsd_start;
> >>>>      unsigned int len;
> >>>>
> >>>> @@ -1851,7 +1852,9 @@ static void mov_parse_stsd_video(MOVContext *c, AVIOContext *pb,
> >>>>
> >>>>      avio_rb16(pb); /* version */
> >>>>      avio_rb16(pb); /* revision level */
> >>>> -    avio_rb32(pb); /* vendor */
> >>>> +    avio_read(pb, vendor, 4);
> >>>> +    if (vendor[0])
> >>>> +        av_dict_set(&st->metadata, "vendor", vendor, 0);  
> >>>
> >>> Does this mean transcoding to a format with per-stream
> >>> tags will add this as a tag?  
> >>
> >> The patch you quoted allows libavformat users to read the
> >> vendor tag from mov files, I don't understand how it adds
> >> tags.
> >> Do you object?  
> >
> > Any metadata you export can and will get copied to a new file when
> > remuxing, therefor exporting arbitrary info that isn't actual stream
> > metadata tags in metadata is problematic - it carries over to the
> > destination file, in which it would be entirely meaningless.  
> 
> Sorry, I don't understand:
> Which application do you mean?

ffmpeg

Or does it somehow have a whitelist of which tags to copy? I didn't
attempt to confirm the behavior.