{"id":16208,"url":"https://patchwork.libcamera.org/api/1.1/patches/16208/?format=json","web_url":"https://patchwork.libcamera.org/patch/16208/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20220613103528.226610-1-kieran.bingham@ideasonboard.com>","date":"2022-06-13T10:35:28","name":"[libcamera-devel] libcamera: v4l2_videodevice: Identify non-zero stream starts","commit_ref":"1c9dc0fd89cfb32d31e25c4d14501c891d329307","pull_url":null,"state":"accepted","archived":false,"hash":"a5b15c2d6ce98d86cf4b421ba89c646c238e2aa4","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/1.1/people/4/?format=json","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/16208/mbox/","series":[{"id":3173,"url":"https://patchwork.libcamera.org/api/1.1/series/3173/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=3173","date":"2022-06-13T10:35:28","name":"[libcamera-devel] libcamera: v4l2_videodevice: Identify non-zero stream starts","version":1,"mbox":"https://patchwork.libcamera.org/series/3173/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/16208/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/16208/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 68D98BD808\n\tfor ;\n\tMon, 13 Jun 2022 10:34:57 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 9CDE565635;\n\tMon, 13 Jun 2022 12:34:56 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 75BBE600F1\n\tfor ;\n\tMon, 13 Jun 2022 12:34:55 +0200 (CEST)","from Q.ksquared.org.uk.beta.tailscale.net (unknown\n\t[178.237.134.231])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id DCBDD268;\n\tMon, 13 Jun 2022 12:34:54 +0200 (CEST)"],"DKIM-Signature":["v=1; 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dkim=pass (1024-bit key; \n\tunprotected) header.d=ideasonboard.com\n\theader.i=@ideasonboard.com\n\theader.b=\"emAQoGXZ\"; dkim-atps=neutral","To":"libcamera devel ","Date":"Mon, 13 Jun 2022 12:35:28 +0200","Message-Id":"<20220613103528.226610-1-kieran.bingham@ideasonboard.com>","X-Mailer":"git-send-email 2.25.1","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","Subject":"[libcamera-devel] [PATCH] libcamera: v4l2_videodevice: Identify\n\tnon-zero stream starts","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","From":"Kieran Bingham via libcamera-devel\n\t","Reply-To":"Kieran Bingham ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "},"content":"V4L2 Video devices should always start streaming from index zero.\nIdentify and report a warning if they don't, and correct for any offset.\n\nSigned-off-by: Kieran Bingham \n---\n\nI'm not yet sure if the Warning print is perhaps just unhelpful.\nIt doesn't really affect us if we have this work around in - so we can\nbe silent, and I'm not yet sure if V4L2 has any 'requirement' that it\nshould start at 0 at every stream on.\n\n include/libcamera/internal/v4l2_videodevice.h | 1 +\n src/libcamera/v4l2_videodevice.cpp | 15 +++++++++++++++\n 2 files changed, 16 insertions(+)","diff":"diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h\nindex 23f37f83f8e2..8525acbc558d 100644\n--- a/include/libcamera/internal/v4l2_videodevice.h\n+++ b/include/libcamera/internal/v4l2_videodevice.h\n@@ -276,6 +276,7 @@ private:\n \tEventNotifier *fdBufferNotifier_;\n \n \tState state_;\n+\tstd::optional firstFrame_;\n \n \tTimer watchdog_;\n \tutils::Duration watchdogDuration_;\ndiff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp\nindex 430715afd554..63911339f96e 100644\n--- a/src/libcamera/v4l2_videodevice.cpp\n+++ b/src/libcamera/v4l2_videodevice.cpp\n@@ -1771,6 +1771,19 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer()\n \tif (V4L2_TYPE_IS_OUTPUT(buf.type))\n \t\treturn buffer;\n \n+\t/*\n+\t * Detect kernel drivers which do not reset the sequence number to zero\n+\t * on stream start.\n+\t */\n+\tif (!firstFrame_) {\n+\t\tif (buf.sequence)\n+\t\t\tLOG(V4L2, Warning)\n+\t\t\t\t<< \"Zero sequence expected for first frame (got \"\n+\t\t\t\t<< buf.sequence << \")\";\n+\t\tfirstFrame_ = buf.sequence;\n+\t}\n+\tbuffer->metadata_.sequence -= firstFrame_.value();\n+\n \tunsigned int numV4l2Planes = multiPlanar ? buf.length : 1;\n \tFrameMetadata &metadata = buffer->metadata_;\n \n@@ -1847,6 +1860,8 @@ int V4L2VideoDevice::streamOn()\n {\n \tint ret;\n \n+\tfirstFrame_.reset();\n+\n \tret = ioctl(VIDIOC_STREAMON, &bufferType_);\n \tif (ret < 0) {\n \t\tLOG(V4L2, Error)\n","prefixes":["libcamera-devel"]}