[Ffmpeg-devel] Re: [PATCH] Configure selectable video grab format

[Måns Rullgård]

Ramiro Polla said:
> Diego Biurrun wrote:
>> On Wed, Jan 31, 2007 at 02:17:52AM -0200, Ramiro Polla wrote:
>>
>>> Diego Biurrun wrote:
>>>
>>>> On Sun, Jan 28, 2007 at 05:51:02PM -0200, Ramiro Polla wrote:
>>>>
>>>>
>>>>> Ok. I used --default-grabber and default_grabber as the variable, as
>>>>> there isn't more than one audio grab format.
>>>>>
>>>> While I like the idea of setting the grab device in configure instead of
>>>> using #ifdef in ffmpeg.c, I don't see why the device should be
>>>> selectable.  Just hardcode it in configure and be done with it.
>>>>
>>>>
>>> Attached patch just moves #ifdefs from ffmpeg.c to configure.
>>>
>>> --- configure	(revision 7760)
>>> +++ configure	(working copy)
>>> @@ -670,6 +670,7 @@
>>>  video4linux="yes"
>>>  video4linux2="yes"
>>>  bktr="no"
>>> +video_grab_format="no"
>>>
> Starts off disabled.
>>>  audio_oss="yes"
>>>  audio_beos="no"
>>>  x11grab="no"
>>> @@ -1802,6 +1803,12 @@
>>>  add_extralibs -lX11 -lXext              ||
>>>  disable x11_grab_device_demuxer
>>>
>>> +# Set default video grab format
>>> +
>>> +enabled bktr               && video_grab_format=bktr
>>>
> The first time it doesn't check wheter it's disabled (we know it is).
>>> +disabled video_grab_format && enabled video4linux2 &&
>>> video_grab_format=video4linux2
>>>
> If it has not been set (bktr was disabled), check for video4linux2.
>>> +disabled video_grab_format && video_grab_format=video4linux
>>>
> If it still hasn't been set, set to video4linux (the same things that
> happens in ffmpeg.c).

Something like this would do the same thing:

enabled bktr &&         video_grab_format=bktr ||
enabled video4linux2 && video_grab_format=video4linux2 ||
                        video_grab_format=video4linux

That said, I don't like the design of the grabbing code at all.  IMHO it would
be much cleaner to simply run ffmpeg -f v4l2 -i /dev/video0 or whatever,
dropping the whole concept of a default grabbing device used if no input is
specified.

-- 
M?ns Rullg?rd
mru at inprovide.com