gst-omx encoder change caps

[BK]

Thanks for your input. Finally I got it working last night. As per doc I
should not be setting the resolution information in input caps instead
those info should be set in the returned GstVideoCodeState.

"The specified *caps* should not contain any resolution,
pixel-aspect-ratio, framerate, codec-data, .... Those should be specified
instead in the returned GstVideoCodecState
<http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstvideoutils.html#GstVideoCodecState>."


But I did tried setting the resolution in input caps which didn't help.
Then I looked at  gst_video_encoder_negotiate_default() implementation
which gave me hint that the width and height information is retrieved from
the state->info{width/height} fields and not from the caps. After setting
the info->width and info->height in the state I see the correct negotiated
caps.

now my code looks like this:

state = gst_video_encoder_set_output_state (GST_VIDEO_ENCODER (self), caps,
self->input_state);
state->info.width = scaling_width;
state->info.height = scaling_height;

 if (!gst_video_encoder_negotiate (GST_VIDEO_ENCODER (self))) {
      if (buf)
        gst_omx_port_release_buffer (self->enc_out_port, buf);
      GST_VIDEO_ENCODER_STREAM_UNLOCK (self);
      goto caps_failed;
   }

    GST_DEBUG_OBJECT (self, "final caps : %" GST_PTR_FORMAT, state->caps);

final cap print the correct caps and gst-launch -v also shows the right
caps.

Thanks
BK





On Fri, Jan 16, 2015 at 5:22 AM, Sebastian Dröge <sebastian at centricular.com>
wrote:

> On Mi, 2015-01-14 at 13:19 -0500, BK wrote:
> > Hi,
> >
> > I am using gst-omx encoder element to support hw accelerated code on my
> > platform. In addition to encode the module also support scaling plus
> > encode. I have added a new property in element to pass the resize
> parameter
> > and its working as expected. But caps still have the old resolution as
> > passed from upstream element. As per the gst plugin doc I am using
> > gst_video_encoder_set_output_state() to change the caps resolution
> > information. Can anyone comment on what I am missing here
> >
> > static void
> > gst_omx_video_enc_loop (GstOMXVideoEnc * self)
> > {
> >
> >
> > ....
> > ...
> > .....
> >     caps = klass->get_caps (self, self->enc_out_port, self->input_state);
> >     if (!caps) {
> >       if (buf)
> >         gst_omx_port_release_buffer (self->enc_out_port, buf);
> >       GST_VIDEO_ENCODER_STREAM_UNLOCK (self);
> >       goto caps_failed;
> >     }
> >
> >     GST_DEBUG_OBJECT (self, "Setting output state: %" GST_PTR_FORMAT,
> caps);
> >
> >     state =
> >         gst_video_encoder_set_output_state (GST_VIDEO_ENCODER (self),
> caps,
> >         self->input_state);
> >      gst_caps_set_simple (state->caps, "width", G_TYPE_INT, 640, NULL);
> >      gst_caps_set_simple (state->caps, "height", G_TYPE_INT, 480, NULL);
> >     GST_DEBUG_OBJECT (self, "requesting caps : %" GST_PTR_FORMAT,
> > state->caps);
>
> You have to change the fields of the caps *before* calling
> gst_video_encoder_set_output_state(), and then pass the caps to that
> function.
>
> By default it will take over any generic fields from the input state
> though, so usually it's not necessary to set width or height manually.
>
>
> Also by giving the caps to gst_video_encoder_set_output_state() you give
> them away and don't own a reference to them anymore, so you're not
> allowed to use them (or change them). If you want to keep a reference
> for yourself you need to call gst_caps_ref() before, but then you still
> can't change them without copying first as they become immutable once
> there are more than 1 references to the caps.
>
> --
> Sebastian Dröge, Centricular Ltd · http://www.centricular.com
>
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
>
>
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