HI William,
I played around with a JPEG-webcam using GSCAM. I needed to make two
tweaks.
1. Install the gstreamer appsink package i.e. "smart install
gst-plugins-base-app". It looks like [1] gscam is tacking this plugin
onto the end of the gstreamer pipeline.
2. Specify the (undocumented) 'image_encoding' parameter as 'jpeg'.
For this, I grabbed the example launch [2] file and added a "<param
name="image_encoding" value="jpeg"/>" line. Perhaps unnecessarily, I
also tweaked the gstreamer pipeline and disabled sync_sink so my
launch file looked like this:
<launch>
<!-- This launchfile should bring up a node that broadcasts a ros image
transport on /webcam/image_raw -->
<arg name="DEVICE" default="/dev/video0"/>
<!-- The GStreamer framerate needs to be an integral fraction -->
<arg name="FPS" default="5/1"/>
<arg name="PUBLISH_FRAME" default="false"/>
<node ns="v4l" name="gscam_driver_v4l" pkg="gscam" type="gscam"
output="screen">
<param name="camera_name" value="default"/>
<param name="gscam_config" value="v4l2src device=$(arg DEVICE) !
image/jpeg,framerate=$(arg FPS) "/>
<param name="frame_id" value="/v4l_frame"/>
<param name="sync_sink" value="false"/>
<param name="image_encoding" value="jpeg"/>
</node>
<node if="$(arg PUBLISH_FRAME)" name="v4l_transform" pkg="tf"
type="static_transform_publisher" args="1 2 3 0 -3.141 0 /world
/v4l_frame 10"/>
</launch>
[1] https://github.com/ros-drivers/gscam/blob/master/src/gscam.cpp
[2]
https://raw.githubusercontent.com/ros-drivers/gscam/master/examples/v4l.launch
HTH,
Ash
On Friday, May 29, 2015 at 3:10:24 PM UTC-7, William Phan wrote:
>
> Hi,
>
> Has anyone been able to get the gscam package working with the meta-ros
> layer? I'm trying to send a live video feed from a webcam attached to a
> Gumstix Overo COM on a Tobi expansion board to a host machine(where roscore
> is running) with Ubuntu 14.04+ROS Indigo. My gumstix-console-image.bb
> includes the following:
>
>
> 89 GSCAM_INSTALL = " \
> 90 gscam \
> 91 nodelet \
> 92 cv-bridge \
> 93 roscpp \
> 94 theora-image-transport \
> 95 sensor-msgs \
> 96 camera-calibration-parsers \
> 97 camera-info-manager \
> 98 "
> 99
> 100 IMAGE_INSTALL += " \
> 101 ${FIRMWARE_INSTALL} \
> 102 ${SYSTEM_TOOLS_INSTALL} \
> 103 ${DEV_TOOLS_INSTALL} \
> 104 ${NETWORK_TOOLS_INSTALL} \
> 105 ${MEDIA_TOOLS_INSTALL} \
> 106 ${GRAPHICS_LIBS} \
> 107 ${UTILITIES_INSTALL} \
> 108 ${GSCAM_INSTALL} \
> 109 "
>
>
> The COM recognizes the webcam (Microsoft LifeCam VX3000) and assigns it to
> /dev/video0.
>
> I then install some missing plugins:
>
> $ smart update
> $ smart install gst-plugins-good-video4linux2
>
> and source the environmental variable:
>
> $ export GSCAM_CONFIG="v4l2src device=/dev/video0 ! video/x-raw-rgb !
> ffmpegcolorspace"
>
> but upon launching the gscam node, I am stuck at the following error
> message:
>
> root@overo:~# rosrun gscam gscam
> [ INFO] [1432936018.001607854]: Using gstreamer config from env: "v4l2src
> device=/dev/video0 ! video/x-raw-rgb ! ffmpegcolorspace"
> [ INFO] [1432936018.140851232]: using default calibration URL
> [ INFO] [1432936018.144604670]: camera calibration URL: file:
> ///home/root/.ros/camera_info/camera.yaml
> [ INFO] [1432936018.147747792]: Unable to open camera calibration file [
> /home/root/.ros/camera_info/camera.yaml]
> [ WARN] [1432936018.151226588]: Camera calibration file /home/root/.ros/
> camera_info/camera.yaml not found.
> [ INFO] [1432936018.153820427]: Loaded camera calibration from
>
> ** (gscam:1952): CRITICAL **: gst_app_sink_set_caps: assertion
> 'GST_IS_APP_SINK
> (appsink)' failed
>
> ** (gscam:1952): CRITICAL **: gst_base_sink_set_sync: assertion
> 'GST_IS_BASE_SINK
> (sink)' failed
>
> (gscam:1952): GStreamer-CRITICAL **: gst_element_link_pads_full:
> assertion 'GST_IS_ELEMENT (dest)' failed
> [FATAL] [1432936020.927885414]: GStreamer: cannot link launchpipe -> sink
> [FATAL] [1432936020.931242147]: Failed to initialize gscam stream!
>
> Based on the error I suspected that GStreamer was the problem, so I ran
> and installed:
> root@overo:~# gst-launch v4l2src device=/dev/video0 ! video/x-raw-rgb !
> ffmpegco
> WARNING: erroneous pipeline: no element "ffmpegcolorspace"
> root@overo:~# smart install gst-plugins-base-ffmpegcolorspace
>
> Now launching gscam again gives the following:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> *root@overo:~# rosrun gscam gscam[ INFO] [1432936847.626166516]: Using
> gstreamer config from env: "v4l2src device=/dev/video0 ! video/x-raw-rgb !
> ffmpegcolorspace"[ INFO] [1432936847.802852723]: using default calibration
> URL[ INFO] [1432936847.806423066]: camera calibration URL:
> file:///home/root/.ros/camera_info/camera.yaml[ INFO]
> [1432936847.811702291]: Unable to open camera calibration file
> [/home/root/.ros/camera_info/camera.yaml][ WARN] [1432936847.815394697]:
> Camera calibration file /home/root/.ros/camera_info/camera.yaml not found.[
> INFO] [1432936847.819422776]: Loaded camera calibration from**
> (gscam:2019): CRITICAL **: gst_app_sink_set_caps: assertion
> 'GST_IS_APP_SINK (appsink)' failed** (gscam:2019): CRITICAL **:
> gst_base_sink_set_sync: assertion 'GST_IS_BASE_SINK (sink)'
> failed(gscam:2019): GStreamer-CRITICAL **: gst_bin_add: assertion
> 'GST_IS_ELEMENT (element)' failed[FATAL] [1432936851.527239271]:
> gst_bin_add() failed[FATAL] [1432936851.531999729]: Failed to initialize
> gscam stream!*
>
> It looks like it is probably a GStreamer problem, any pointers or
> suggestions will be much appreciated!
> William
>
