[FFmpeg-user] 'print:file=foo.txt' fails

[Mark Filipak]

On 02/06/2020 06:39 AM, Paul B Mahol wrote:
> On 2/6/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>> On 02/06/2020 03:35 AM, Paul B Mahol wrote:
>>> On 2/6/20, Mark Filipak <markfilipak.windows+ffmpeg at gmail.com> wrote:
>>>> The command line below creates 'foo.txt' but the file is empty (i.e.,
>>>> zero length).
>>>>
>>>> Any clues why?
>>>
>>> Because your file does not have any _frame_ metadata.
>>
>> What am I missing here? The file is VTS_02_2.VOB. It contains all the
>> metadata that a VOB usually contains.
>>
>> It contains one pack per sector. The packs are aggregated into GOPs with
>> I-frames and P-frames and B-frames. Each frame has a PES & MPEG2
>> sequence header and all the metadata. I can see them with VOBEdit.
>>
>> Why can't I list the metadata with ffmpeg?
> 
> You are deeply confused. Frame metadata is not what you think it is.
> You are looking for packet metadata, while frame metadata is something
> completely else.
> 
>>
>> Can ffmpeg list metadata?
> 
> Yes.

Thanks, Paul.

Can ffmpeg list the metadata I'm interested in? I don't know what's in 
the MPEG frame -- I didn't know there was metadata in there; I thought 
it was just pixels.

I'm interested in the metadata in the MPEG2 packet. Can ffmpeg read that?