From 1c9dc0fd89cfb32d31e25c4d14501c891d329307 Mon Sep 17 00:00:00 2001 From: Kieran Bingham Date: Mon, 2 May 2022 16:42:49 +0200 Subject: libcamera: v4l2_videodevice: Identify non-zero stream starts V4L2 Video devices should always start streaming from index zero. Identify and report a warning if they don't, and correct for any offset. Reviewed-by: Jacopo Mondi Reviewed-by: Laurent Pinchart Signed-off-by: Kieran Bingham --- include/libcamera/internal/v4l2_videodevice.h | 1 + src/libcamera/v4l2_videodevice.cpp | 15 +++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h index 23f37f83..8525acbc 100644 --- a/include/libcamera/internal/v4l2_videodevice.h +++ b/include/libcamera/internal/v4l2_videodevice.h @@ -276,6 +276,7 @@ private: EventNotifier *fdBufferNotifier_; State state_; + std::optional firstFrame_; Timer watchdog_; utils::Duration watchdogDuration_; diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp index 430715af..63911339 100644 --- a/src/libcamera/v4l2_videodevice.cpp +++ b/src/libcamera/v4l2_videodevice.cpp @@ -1771,6 +1771,19 @@ FrameBuffer *V4L2VideoDevice::dequeueBuffer() if (V4L2_TYPE_IS_OUTPUT(buf.type)) return buffer; + /* + * Detect kernel drivers which do not reset the sequence number to zero + * on stream start. + */ + if (!firstFrame_) { + if (buf.sequence) + LOG(V4L2, Warning) + << "Zero sequence expected for first frame (got " + << buf.sequence << ")"; + firstFrame_ = buf.sequence; + } + buffer->metadata_.sequence -= firstFrame_.value(); + unsigned int numV4l2Planes = multiPlanar ? buf.length : 1; FrameMetadata &metadata = buffer->metadata_; @@ -1847,6 +1860,8 @@ int V4L2VideoDevice::streamOn() { int ret; + firstFrame_.reset(); + ret = ioctl(VIDIOC_STREAMON, &bufferType_); if (ret < 0) { LOG(V4L2, Error) -- cgit v1.2.1