Error in video scaling

[Tim-Philipp Müller]

On Sat, 2013-09-28 at 13:04 +0200, JPM wrote:

Hi,

> There are not errors with the changes you suggest but it seems that
> the scaling process is not working because
> the video has lot of artifacts and this happen when Galaxy mini 2
> mobile phone receives video with a resolution
> greater than 320x240.

Well, you are both decoding and scaling in software here on an embedded
system. First thing to check: do you get artefacts if you don't scale as
well. Secondly: add an gstrtpjitterbuffer and/or a queue after udpsrc -
otherwise udp packets will be dropped if the decoding/scaling takes too
long, and then you'll get artefacts. This might happen in any case if
decoding/scaling takes too much cpu.

Cheers
 -Tim

> 2013/9/28 Tim-Philipp Müller <t.i.m at zen.co.uk>
>         On Fri, 2013-09-27 at 14:30 +0200, JPM wrote:
>         
>         Hi,
>         
>         > The Android device (Samsung Galaxy mini 2, Android 2.3.6) is
>         receiving
>         > a video stream H264 over RTP over UDP.
>         > The video resolution is 1024x768 but I want to downscaling
>         it to
>         > 320x240 with this pipeline :
>         >
>         >
>         > data->pipeline = gst_parse_launch("udpsrc port=5001 !
>         > application/x-rtp, payload=96 ! rtph264depay ! ffdec_h264 !
>         > videoscale ! video/x-raw, width=320, height=240 !
>         autovideosink
>         > sync=false", &error);
>         >
>         >
>         > It does not work, there is the following error : Unable to
>         build
>         > pipeline: could not link videoscale0 to autovideosink0
>         
>         
>         I'm guessing that you're using the old 0.10 version and not
>         the new
>         official GStreamer 1.0 SDK packages from
>         http://gstreamer.freedesktop.org/pkg/android/
>         
>         The format for raw audio/video caps was slightly different in
>         0.10. You
>         are using the 1.0-style caps here in your pipeline.
>         
>         Try something like:
>         
>         udpsrc port=5001 ! application/x-rtp, payload=96 !
>         rtph264depay !
>         
>         ffdec_h264 ! videoscale !
>         video/x-raw-yuv,width=320,height=240 !
>         ffmpegcolorspace ! autovideosink sync=false
>         
>         (in case you ever do want to show the stream with proper sync
>         I would
>         suggest you also add a gstrtpjitterbuffer after the udpsrc).
>         
>         Cheers
>          -Tim
>         
>         
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