[FFmpeg-devel] [PATCH v4 3/3] avformat/mxfenc: prefer to use the configured metadta

[Tomas Härdin]

ons 2021-01-20 klockan 00:27 +0100 skrev Marton Balint:
> 
> On Tue, 19 Jan 2021, Tobias Rapp wrote:
> 
> > On 18.01.2021 23:53, Tomas Härdin wrote:
> > > lör 2021-01-16 klockan 08:43 +0800 skrev lance.lmwang at gmail.com:
> > > > On Fri, Jan 15, 2021 at 09:43:58PM +0100, Marton Balint wrote:
> > > > > On Fri, 15 Jan 2021, Tomas Härdin wrote:
> > > > > > Again, why? If you have a company that maintains a fork of FFmpeg then
> > > > > > compile that info in here instead. Compare with FFmbc which always puts
> > > > > > "FFmbc" as CompanyName.
> > > > > 
> > > > > And how can a product based on libavformat set the company name, product
> > > > > name and product version? It seems a valid use case for me that these are
> > > > > overridable. Also note that this product version is only the "user 
> > friendly"
> > > > > version string, for the numeric version still LIBAVFORMAT_VERSION values 
> > are
> > > > > used.
> > > > 
> > > > Yes, my use case is the product is using libavformat as library, so it's
> > > > prefer to have way to override these information as requirements.
> > > 
> > > What I'm worried about here is that we're going to get files which
> > > claim to have been written by something other than libavformat. I've
> > > had situations like this before, and it is a source of headache. For
> > > example, if mxfenc writes some field incorrectly then this might cause
> > > us to hack mxfdec to accept that field instead of fixing mxfenc.
> > 
> > I agree that especially for the MXF format with its flexible structure 
> > it is more relevant to know the muxing library rather than the hosting 
> > application. Have seen MXF output files of other commercial products 
> > that also contain library identifiers like "libMXF" or "MXFtk" here.
> > 
> > Other formats in FFmpeg use the "encoder" metadata key for embedding 
> > library information in the output file. A quick test with AVI output 
> > shows that this metadata is generated internally and cannot be 
> > overridden on the command-line.
> 
> If your concern is being able to identify our mxf muxer, then why not use 
> the Platform metadata item for this?
> 
> "Human readable name of the toolkit and operating system used. Best 
> practice is to use the form “SDK name (OS name)”"

Where is this text from? Neither S377m-2004 nor RP210v10-2007 says
this.

/Tomas