From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001 From: root Date: Fri, 25 Dec 2015 04:40:36 +0000 Subject: initial_commit --- Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml | 180 ++++++++++++++++++++++++ 1 file changed, 180 insertions(+) create mode 100644 Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml (limited to 'Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml') diff --git a/Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml b/Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml new file mode 100644 index 00000000..77394b28 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-jpegcomp.xml @@ -0,0 +1,180 @@ + + + ioctl VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP + &manvol; + + + + VIDIOC_G_JPEGCOMP + VIDIOC_S_JPEGCOMP + + + + + + + int ioctl + int fd + int request + v4l2_jpegcompression *argp + + + + + int ioctl + int fd + int request + const v4l2_jpegcompression *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_JPEGCOMP, VIDIOC_S_JPEGCOMP + + + + argp + + + + + + + + + Description + + [to do] + + Ronald Bultje elaborates: + + + + APP is some application-specific information. The +application can set it itself, and it'll be stored in the JPEG-encoded +fields (eg; interlacing information for in an AVI or so). COM is the +same, but it's comments, like 'encoded by me' or so. + + jpeg_markers describes whether the huffman tables, +quantization tables and the restart interval information (all +JPEG-specific stuff) should be stored in the JPEG-encoded fields. +These define how the JPEG field is encoded. If you omit them, +applications assume you've used standard encoding. You usually do want +to add them. + + + + + struct <structname>v4l2_jpegcompression</structname> + + &cs-str; + + + int + quality + + + + int + APPn + + + + int + APP_len + + + + char + APP_data[60] + + + + int + COM_len + + + + char + COM_data[60] + + + + __u32 + jpeg_markers + See . + + + +
+ + + JPEG Markers Flags + + &cs-def; + + + V4L2_JPEG_MARKER_DHT + (1<<3) + Define Huffman Tables + + + V4L2_JPEG_MARKER_DQT + (1<<4) + Define Quantization Tables + + + V4L2_JPEG_MARKER_DRI + (1<<5) + Define Restart Interval + + + V4L2_JPEG_MARKER_COM + (1<<6) + Comment segment + + + V4L2_JPEG_MARKER_APP + (1<<7) + App segment, driver will always use APP0 + + + +
+ + + + &return-value; + + + + EINVAL + + This ioctl is not supported. + + + + + + + -- cgit v1.2.3