[FFmpeg-devel] [PATCH] [2/??] [3/3] Filter graphs - Parser for a graph description

[Vitor Sessak]

Hi

Michael Niedermayer wrote:
> On Mon, Feb 25, 2008 at 06:36:40PM +0100, Vitor Sessak wrote:
> [...]
>>>> And for
>>>>
>>>>   in --> crop --> rotate --> vflip --> out
>>>>
>>>> crop=400:300,rotate=1,vflip,split
>>> yes (in) (out) should be default at the ends
>>>
>>>
>>>> meaning that when there is no semicolon, the (in) in the beginning and 
>>>> the (out) in the end can be omitted. 
>>>> Also, I don't understand the point 
>>>> of explicitly putting a "+" in new vertexes...
>>> filter1(abc),(def)filter2
>>>
>>> filter1->(abc)
>>> (def)->filter2
>>>
>>> filter1(+abc),(+def)filter2
>>>
>>> filter1->filter2
>>>   |         ^
>>>   v         |
>>> (abc)     (def)
>>>
>>> again, this was all just an idea ...
>>> your ';' achives the same, though it adds an additional char to the ones
>>> needing escaping if used in filters. Iam not even sure if we shoud use ',' as
>>> filter seperator ...
>>> '|' would be an alternative but it would need filter chains to be under ""
>>> though that applies to ; () [] as well
>> I prefer the comma. I like the syntax
>>
>> ffmpeg -i in.avi -vfilters vflip,scale=300:400 out.avi
>>
>> so as for filter graphs that are just a chain we have a simple, 
>> unescaped command line. If for more complex graphs "" are needed, it 
>> bother me less.
>>
>>> other random ideas ...
>>>
>>> crop=400:300|[tmp1]picInPic=50:50|rotate=1|split[tmp2]|vflip[out];[tmp2]hflip|delay[tmp1]
>>>
>>> crop=400:300 | [tmp1]picInPic=50:50 | rotate=1 | split[tmp2] | vflip[out] ; [tmp2]hflip | delay[tmp1]
>>>
>>> crop=400:300 | [tmp1] picInPic=50:50 | rotate=1 | split [tmp2] | vflip [out] ; [tmp2] hflip | delay [tmp1]
>> Wouldn't it be a good idea to ignore whitespace and newlines completely?
> 
> That was the idea, sorry ive just been testing how different whitespace
> placements would look ...
> 
> 
>>> crop=400:300 | [tmp1] picInPic=50:50 | rotate=1 | split {hflip | delay[tmp1];} | vflip
>>>
>>>
>>>
>>>> Finally, I prefer parenthesis instead of brackets... What do you think?
>>> Passing eval.c equation like sin(5)*eq(a,b) might get trickier escaping
>>> wise and parsing wise with (), besides this iam fine with () as well, that
>>> is if you provide a solution to passing equations to eval based filters
>>> without requireing each () to be escaped individually.
>> I agree. But I'll have to add quotes to the syntax anyway for thing like
>>
>> vflip,drawtext='text, a   =)   :-]':arial:10:10,hflip
> 
> well mplayer survivied without proper quote handling, and that results in
> eval stuff looking really nasty ...

Well, this is more of a RFC than a patch, since parsers are not my 
strong point. The file was rewritten almost from scratch. Now the it 
accepts things like

  (  in  )   split(i1),fifo,(i2)overlay=0:240(out);(i1)vflip(i2)

or

vflip,scale=10:30

-Vitor
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