From: GStreamer (bugzilla.gnome.org) <bug...@bu...> - 2009-04-04 21:01:19
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If you have any questions why you received this email, please see the text at the end of this email. Replies to this email are NOT read, please see the text at the end of this email. You can add comments to this bug at: http://bugzilla.gnome.org/show_bug.cgi?id=577963 GStreamer | gst-plugins-good | Ver: 0.10.22 Summary: v4l2src doesn't work with yuv420 and a 356x292 resolution Product: GStreamer Version: 0.10.22 Platform: Other OS/Version: All Status: UNCONFIRMED Severity: major Priority: Normal Component: gst-plugins-good AssignedTo: gst...@li... ReportedBy: eri...@gm... QAContact: gst...@li... GNOME version: 2.25/2.26 GNOME milestone: Unspecified Please describe the problem: I'm developing a driver for stv06xx based webcams (Quickcam Web, Dexxa Webcam, Quickcam Express etc.) Some of these webcams contain a vv6410 sensor producing a raw bayer image with a 356x292 resolution. As the camera only supports bayer natively the libv4l [1] library is used to convert the format to rgb or yuv. RGB works fine but I'm having trouble to get yuv conversion working together with gstreamer. This is due to that the U V plane widths are rounded up by 8 in gstv4l2src.c libv4l delivers 356*292+(356*292/2) = 155928 byte frames but gstreamer expects 356+292+(360*292/2) = 156512 byte frames and thus bails out. If I've understood things correctly, gstreamer expects us to pad each line with two bytes, but the v4l2 standard [2] says that the driver may choose to ignore padding and this is as of current not honoured by gstreamer. I've hacked gstv4l2src.c to only round up by 4 but I still get an corrupt image. My take is that the rounding by 8 is presumed elsewhere in the gstreamer stack. Other yuv420 consuming applications (skype for instance) work correctly and doesn't expect this alignment. My questions are as following: 1. Why is the rounding by 8 taking place? Is this defined somewhere in yuv420 specification? 2. How do we resolve this issue? AFAICS the gstreamer stack is currently violating the specs as it expects the padding. Would this be easy to fix? [1] http://hansdegoede.livejournal.com/3636.html [2] http://www.linuxtv.org/downloads/video4linux/API/V4L2_API/spec/c2030.htm#V4L2-PIX-FORMAT Steps to reproduce: 1. Run the following command from the commandline: gst-launch-0.10 v4l2src queue-size=4 ! ffmpegcolorspace ! xvimagesink Actual results: Gstreamer fails to produce an image Expected results: Normal usage Does this happen every time? Yes Other information: -- See http://bugzilla.gnome.org/page.cgi?id=email.html for more info about why you received this email, why you can't respond via email, how to stop receiving emails (or reduce the number you receive), and how to contact someone if you are having problems with the system. You can add comments to this bug at http://bugzilla.gnome.org/show_bug.cgi?id=577963. |