8. Stores the buffer to a YCrCb file.
9. Replaces the buffer in the queue of the V4L2 driver by executing VIDIOC_QBUF
again.
For the V4L2 still image capture process, the application completes the following steps:
1. Sets the capture pixel format and size by executing the IOCTL VIDIOC_S_FMT.
2. Reads one frame still image with YUV422.
For the V4L2 overlay support use case, the application completes the following steps:
1. Sets the overlay window by IOCTL VIDIOC_S_FMT.
2. Turns on overlay task by IOCTL VIDIOC_OVERLAY.
3. Turns off overlay task by IOCTL VIDIOC_OVERLAY.
8.3 V4L2 Output Device
The V4L2 output driver uses the IPU post-processing functions for video output.
The driver implements the standard V4L2 API for output devices. V4L2 output device
support can be selected during kernel configuration. The driver is available at <ltib_dir>/
rpm/BUILD/linux/drivers/media/video/mxc/output/mxc_vout.c.
8.3.1 V4L2 Output IOCTLs
Currently, the memory map stream API is supported. Supported V4L2 IOCTLs include
the following:
• VIDIOC_QUERYCAP
• VIDIOC_REQBUFS
• VIDIOC_G_FMT
• VIDIOC_S_FMT
• VIDIOC_QUERYBUF
• VIDIOC_QBUF
• VIDIOC_DQBUF
• VIDIOC_STREAMON
• VIDIOC_STREAMOFF
• VIDIOC_G_CTRL
• VIDIOC_S_CTRL
• VIDIOC_CROPCAP
• VIDIOC_G_CROP
Chapter 8 Video for Linux Two (V4L2) Driver
i.MX 6Solo/6DualLite Linux Reference Manual, Rev. L3.0.35_4.1.0, 09/2013
Freescale Semiconductor, Inc.
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