[gst-devel] videoparse element arguments

Tadej Borovšak tadeboro at gmail.com
Tue Jun 2 17:11:59 CEST 2009


Hello everyone.

For starters, I'm completely new to GStreamer (I read the app
developers manual and browsed through the API docs, but that's it).

I'm trying to create video slideshow using GStreamer, but I'm having
troubles with videoparse element.

In real world, image manipulation part of the application produces
video frames that I wish to feed to the videoparse element. The
pipeline I intend to use in final application will probably look
something like this: appsrc ! videoparse <attributes> ! ... !
xvimagesink.

For testing purposes, I created a single video frame and copied it to
the data file. Frame is 100 x 100 px in size, each pixel is
represented by 3 bytes (RGB values are represented with 1 byte each) -
basically this is a PPM image format without the header information
and in native endianess. The thing that puzzles me is what are the
correct attributes' values for videoparse element? My guess would be:
width = 100, height = 100, format = 10, bpp =24, depth = 24. (I'm
sorry if this is a stupid question.)

In a attempt to put my selected settings to a test, I made 100 copies
of sample frame, placed it in "test.data" file and tried executing
following pipeline:

gst-launch-0.10 filesrc location=test.data ! videoparse bpp=24
depth=24 height=100 width=100 framerate=10/1 format=10 ! autovideosink

This attempt failed with: "ERROR: from element
/GstPipeline:pipeline0/GstVideoParse:videoparse0: Internal data stream
error." Additional debug info was: "stream stopped, reason
not-negotiated". Any ideas what did I do wrong?

Thanks in advance.


P.S.: I attached my frame creation application below, if anyone is
interested in details. To re-create my test env, you should run those
commands:

$ gcc -o create_ppm create_ppm.c
$ ./create_ppm 1 > test.ppm
$ i=0; while [ $i -lt 100 ]; do let i+=1; ./create_ppm; done > test.data

-- 
Tadej Borovšak
tadeboro.blogspot.com
tadeboro at gmail.com
tadej.borovsak at gmail.com
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