From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from oyp.chewa.net ([91.121.6.101]:50054 "EHLO oyp.chewa.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754898Ab2DKK1V (ORCPT ); Wed, 11 Apr 2012 06:27:21 -0400 To: Subject: UVC frame interval inconsistency MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Date: Wed, 11 Apr 2012 12:27:08 +0200 From: =?UTF-8?Q?R=C3=A9mi_Denis-Courmont?= Message-ID: Sender: linux-media-owner@vger.kernel.org List-ID: Hello guys, I have been reworking the V4L2 input in VLC and I hit what looks like a weird bug in the UVC driver. I am using a Logitech HD Pro C920 webcam. By default, VLC tries to find the highest possible frame rate (actually smallest frame interval in V4L2), then the largest possible resolution at that frame rate. When enumerating the frame sizes and intervals on the device, the winner is 800x600 at 30 f/s. But when setting 30 f/s with VIDIOC_S_PARM, the system call returns 24 f/s. Does anyone know why it is so? Is this a firmware bug or what? -- Rémi Denis-Courmont Sent from my collocated server