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Re: [pandaboard] Re: Regarding omx h264 decoder delay in live video streaming


rob Sep 1, 2011 9:00 PM
Posted in group: pandaboard
On Thu, Sep 1, 2011 at 5:23 PM, wolfgar <stepha...@gmail.com> wrote:
> I answer myself :
>
> I was stupid : The ducati decoder is unable to output another format
> than NV12. I was fooled by the generic API but in fact we have to
> stick to NV12 format...

yes, only NV12

> After getting errors when I tried to create the codec with another
> format I found the H264_Decoder_HDVICP2_UserGuide and I understood
> that I am out of luck to get another format out of the ducati
> decoder ...
>
> So I will switch to a software conversion from NV12 to I420...
>
> Yet, I have another silly question : gst-ducati advertises caps with
> padded dimensions.
> How the gstreamer video sinks are supposed to extract the useful part
> of the image and to know the "real" dimensions ?
> I thank you for any help...

There is a crop event that is pushed downstream towards the sink
element to tell what are the real dimensions and what part of the
buffer should be displayed

See the GST_EVENT_CROP stuff in v4l2sink (on TI branch) for example

BR,
-R

> Regards,
>