jpegenc a theora playbin2 buffer?

[Tim-Philipp Müller]

On Mon, 2011-09-19 at 21:06 -0400, Erik Blankinship wrote:

> Here is the code I use to extract a pixbuf:
> 
> 
>         caps = last_frame.get_caps( )[0]
>         width = int(caps["width"])
>         height = int(caps["height"])
>         r4 = width * 3
>         r4 = (r4 + 3) & ~ 3
>         pixBuf = gtk.gdk.pixbuf_new_from_data( last_frame.data,
> gtk.gdk.COLORSPACE_RGB, False, 8, width, height, r4 )
>
> and here are the results with rowstride set to width * 2: (..)
> and with width * 3: (...)
> and with width * 4: (...)
>
> Hopefully some can suggest what the rowstride should be based on these
> images, or suggest how I would determine what it should be?

Rowstrides are implicit, but there are helper function in libgstvideo
[1] which will tell you what the strides are.

*However*, what you're doing here isn't really going to work reliably.

If you get the last frame via the last-frame property, you have very
little control over what format it will be in. It may be RGB24, RGB32,
RGB15, BGR*, some YUV layout, AYUV, ARGB - pretty much anything (unless
you know exactly what sink is used and that sink only accepts exactly
one format).

It's best not to use the last-frame property at all.

If you want to get an RGB buffer, use the "convert-frame" action signal
to get an RGB buffer in the exact format you need for GdkPixbuf, like
the totem code I linked to does.

 Cheers
  -Tim


[1]
http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/gst-plugins-base-libs-gstvideo.html