Re: support MJPEG based webcams

[Ioannis Nousias <s0238762 sms ed ac uk>]

> i wouldnt just add a gst element, just because it doesnt do anything.
> this can have performance regressions and stuff of that kind.
>
> daniel
>
>   
Hi daniel,

When the input is raw, 'decodebin' creates ghost pads (proxy), which do 
have some overhead (dereferencing?), but it's negligible. I've done a 
simple test with 30 or so cascaded 'decodebin's and there was no 
measurable CPU difference. It does affect the creation-time of the 
pipeline though, by adding type checks, but that's probably similar to 
adding custom checks for the input format.

It's just more flexible this way. Currently, it ignores any format that 
isn't raw. Sure, a custom check and a  conditional addition of a 
'jpegdec' would do the trick in my case, but what about other cases 
(unforeseen)? Similarly to why you use ffmpegcolorspace rather than 
manually handling some types only.

what do you think?


regards,
Ioannis