[gst-devel] Two v4lsrc related problems

Ronald Bultje rbultje at ronald.bitfreak.net
Thu Apr 1 07:30:18 CEST 2004


On Thu, 1 Apr 2004, Thomas [ISO-8859-1] Kuleßa wrote:
> 1. I defined a three element pipe inside a GstThread of the form
> "v4lsrc->myfilter->xvimagesink". In principle this works, but I am not
> able to change the tuner channel of the v4lsrc (it is a TV tuner card).
> When I call the gst_tuner_get_channel() function after setting the
> channel to e.g. S-Video, it is still on the default (TV). I tracked this
> down and it seems that the ioctl call in v4l_calls.c in the v4l plugin
> directory fails.
> I compared my code to the specific parts in gst-record, but it seems
> very similar.

v4l has no way of acquiring the current channel, so this part breaks
easily. I keep the last-set channel in a variable, but maybe I broke that
some day. Please make a bug report for this.

> 2. Another problem I encountered just yesterday is that the pipe
> "videotestsrc ! myfilter ! xvimagesink" works as it is supposed, but
> "v4lsrc ! myfilter ! xvimagesink" results in a broken image. Perhaps it
> has something to do with incorrect image dimensions/formats during
> tramsformation.
> Obviously the error is in myfilter, but in both cases its inputs,
> outputs are YUV2 buffers.

I cannot reproduce this, filters work fine for me... Can you provide
source for the filter?


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