<div dir="ltr">This problem is caused by the videobox element, which I had been using because I needed Y444 support at one point. I don't now, and can use videocrop instead, which doesn't exhibit this issue.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On 16 June 2016 at 15:41, Duncan Palmer <span dir="ltr"><<a href="mailto:dunk.palmer@gmail.com" target="_blank">dunk.palmer@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div>Hi,<br><br></div>I have a pipeline I use to compose a video stream from multiple cameras. I've found a problem whereby blacks appear as 'flickery white' in the resulting image. This problem only appears when I blend using pixel formats which contain an alpha channel, and using images below a certain height. <br><br></div>The following example feeds a 1280x577 stream to the compositor, and does not exhibit the problem;<br><br>gst-launch-1.0 uridecodebin uri=file://`pwd`/b.1.mkv ! videobox top=143 ! videorate ! 'video/x-raw,framerate=25/1,format=AYUV' ! compositor ! glimagesink<br><br></div>The following example feeds a 1280x576 stream to the compositor, and does exhibit the problem (the '576' is a bit of a red flag perhaps?).<br><br>gst-launch-1.0 uridecodebin uri=file://`pwd`/b.1.mkv ! videobox
top=144 ! videorate ! 'video/x-raw,framerate=25/1,format=AYUV' !
compositor ! glimagesink<br><br></div>I'm still digging, but feel this could take some time. Can anyone offer suggestions or point me in a direction for investigation? The problem occurs with both the software and gl compositors.<br><br></div>Note: I force the used of an alpha pixel format in the pipeline above, to produce a small example, but in practice I insert the alpha element. I'm also showing only one video source; in practice I use more.<br><br></div>Cheers,<br></div>Dunk<br><div><div><div><div><br><div><br><br></div></div></div></div></div></div>
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