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

Hendrik Leppkes h.leppkes at gmail.com
Thu Jan 26 01:19:39 EET 2017


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.

- Hendrik


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