[FFmpeg-devel] [PATCH] Stream specifier enhancement
cus at passwd.hu
Sun Oct 18 01:10:50 CEST 2015
On Thu, 15 Oct 2015, Bodecs Bela wrote:
>>> My enhancement does not alter the current behaviour in any way.
>> Are you sure? What if somebody matched a semicolon, or a string which
>> contained a semicolon in a metadata value? E.g.: m:timecode:00:00:00:00
This question still stands. Will the m:timecode:00:00:00:00 specifier work
the same way as it did after your patch? I think it will not.
> I do not understand this. My patch only gives an opportunity to use
> multiple specifiers in the same expression, it is not mandatory to use
> it. The patch does not affect any existing command line in any way.
I don't agree, I think your patch changes existing behaviour and the
proposed syntax limits future extensibility.
> I also accept your concern about the future, but double semicilon always
> will works for optional parameters. But may I ask: would it be better to
> introduce a "special character" for separating specifiers in the same
IMHO yes. You also have to know from the start that you are dealing with a
complex specifier, in order not to break existing simple specifiers.
> I accept it if you suggest one. I only need the functionality to be able
> to give more criteria to select a stream as opposed to current
> oppurtunities. I am not stuck to my suggestion.
> Anyway, You may see my enhancement as you get many optional parameters
> for the existing type, metadata and program_id specifiers. :)
It can be anything if it does not change existing behaviour, a complex
specifier can be split to basic specifiers without worrying about the
syntax of the basic specifier and if there is a well defined rule for
escaping special characters. Also if it is readable to the user, that is a
The exact solution can be a bit about personal taste as well, but maybe
can work and is readable. Knowing that you are dealing with a complex
expression also means that the special characters separating the basic
specifiers needs escaping, I guess av_get_token can be used to get the
proper unescaped basic specifiers when parsing the complex one.
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