[gst-devel] dc1394 : slow framerate and bayer

[Samuel Vinson]

Jan Schmidt a écrit :
> Samuel Vinson wrote:
>> Hi,
>>
>> I use dc1394 plugin on windows XP (with libdc1394 patch 
>> [https://sourceforge.net/tracker/index.php?func=detail&aid=1727980&group_id=8157&atid=308157]) 
>>
>> with avt guppy f033C.
>>
>> I have two questions :
>>
>> 1 .Plugin works nearly fine, but I obtain one frame /sec  with the 
>> following pipeline :
>> dc1394src ! ffmpegcolorspace ! directdrawsink.
>> The messages give a framerate of 60/1. When I use only libdc1394 I 
>> have a best framerate.
>> Do you have an idea to obtain a framerate better than it ?
>
> The frames are probably being dropped in the sink because they arrive 
> too late. To avoid that the, dc1394src element should provide a clock, 
> which it currently doesn't.
>
> As a workaround, turn off sync in the directdrawsink, and you should 
> probably add a queue for decoupling the input/output too:
>
> gst-launch dc1394src ! queue ! ffmpegcolorspace ! directdrawsink 
> sync=false
Thank you for your solution, it works. Queue is not necessary.
Does it exist an example or plugin provides a clock. Perhaps, I can add 
this functionality in dc1394src.

>
>> 2. The guppy cameras use bayer algorithm to transmit the video.
>> How make debayer the video ?
>
> There is a bayer2rgb element that was recently added to 
> gst-plugins-bad, but it will require some extra work on dc1394src for 
> it know that the frames are bayer format and mark the buffers 
> accordingly. Without that, the src element can't link to the bayer2rgb 
> element, because the caps won't match.
Yes I saw. But libdc1394 provides several bayer methods. So it should be 
easier to process frame in dc1394src with parameter. This solution could 
be less generic ?

Samuel