[FFmpeg-devel] [PATCH] avformat/apngenc: use the stream parameters extradata if no updated one is made available
h.leppkes at gmail.com
Thu Nov 3 20:53:24 EET 2016
On Thu, Nov 3, 2016 at 7:39 PM, Andreas Cadhalpun
<andreas.cadhalpun at googlemail.com> wrote:
> On 03.11.2016 09:52, Hendrik Leppkes wrote:
>> Hence my point about trying to stick to a common behavior scheme
>> without looking at what *OUR* decoder needs - there could be others,
>> after all.
>> Its common to write extradata into codecpar if its present. You can
>> try to dispute that as long as you wish, but that doesn't make it any
>> less true.
>> avcodec is not the only thing people use avformat with, and
>> vice-versa, so sticking to common patterns makes the life easier for
>> Do we really need to write this down somewhere to convince you, what
>> do we have the ML for then if we can't inform contributors about
>> common practice?
> What you need to convince me are good arguments.
> The reason why I asked about documentation is that if it's not documented,
> your argument about other decoders, that you repeated above, is void,
> because others shouldn't rely on undocumented behavior, as our
> documentation states clearly :
> "Behavior in undocumented situations may change slightly (and be documented)."
> So if you want to be able to rely on the behavior you describe, you'll
> have to get it documented.
> As you seem to care about this a lot, I don't understand why you appear
> to be opposed to the idea of documenting it.
Since you want docs, I even found one extremely specific to this
"All headers, but the PNG signature, up to (but not including) the
first fcTL chunk are transmitted as extradata."
I'm sure you will argue that side-data is still extradata of some
sort, but fact is the apng demuxer changed behavior recently, and the
documentation suggests a certain content of extradata is to be
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