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-audio.xml | 188 +++++++++++++++++++++++++++ 1 file changed, 188 insertions(+) create mode 100644 Documentation/DocBook/v4l/vidioc-g-audio.xml (limited to 'Documentation/DocBook/v4l/vidioc-g-audio.xml') diff --git a/Documentation/DocBook/v4l/vidioc-g-audio.xml b/Documentation/DocBook/v4l/vidioc-g-audio.xml new file mode 100644 index 00000000..65361a8c --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-audio.xml @@ -0,0 +1,188 @@ + + + ioctl VIDIOC_G_AUDIO, VIDIOC_S_AUDIO + &manvol; + + + + VIDIOC_G_AUDIO + VIDIOC_S_AUDIO + Query or select the current audio input and its +attributes + + + + + + int ioctl + int fd + int request + struct v4l2_audio *argp + + + + + int ioctl + int fd + int request + const struct v4l2_audio *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_AUDIO, VIDIOC_S_AUDIO + + + + argp + + + + + + + + + Description + + To query the current audio input applications zero out the +reserved array of a &v4l2-audio; +and call the VIDIOC_G_AUDIO ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video input. + + Audio inputs have one writable property, the audio mode. To +select the current audio input and change the +audio mode, applications initialize the +index and mode +fields, and the +reserved array of a +v4l2_audio structure and call the +VIDIOC_S_AUDIO ioctl. Drivers may switch to a +different audio mode if the request cannot be satisfied. However, this +is a write-only ioctl, it does not return the actual new audio +mode. + + + struct <structname>v4l2_audio</structname> + + &cs-str; + + + __u32 + index + Identifies the audio input, set by the +driver or application. + + + __u8 + name[32] + Name of the audio input, a NUL-terminated ASCII +string, for example: "Line In". This information is intended for the +user, preferably the connector label on the device itself. + + + __u32 + capability + Audio capability flags, see . + + + __u32 + mode + Audio mode flags set by drivers and applications (on + VIDIOC_S_AUDIO ioctl), see . + + + __u32 + reserved[2] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Audio Capability Flags + + &cs-def; + + + V4L2_AUDCAP_STEREO + 0x00001 + This is a stereo input. The flag is intended to +automatically disable stereo recording etc. when the signal is always +monaural. The API provides no means to detect if stereo is +received, unless the audio input belongs to a +tuner. + + + V4L2_AUDCAP_AVL + 0x00002 + Automatic Volume Level mode is supported. + + + +
+ + + Audio Mode Flags + + &cs-def; + + + V4L2_AUDMODE_AVL + 0x00001 + AVL mode is on. + + + +
+ + + + &return-value; + + + + EINVAL + + No audio inputs combine with the current video input, +or the number of the selected audio input is out of bounds or it does +not combine, or there are no audio inputs at all and the ioctl is not +supported. + + + + EBUSY + + I/O is in progress, the input cannot be +switched. + + + + + + + -- cgit v1.2.3