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-modulator.xml | 246 +++++++++++++++++++++++ 1 file changed, 246 insertions(+) create mode 100644 Documentation/DocBook/v4l/vidioc-g-modulator.xml (limited to 'Documentation/DocBook/v4l/vidioc-g-modulator.xml') diff --git a/Documentation/DocBook/v4l/vidioc-g-modulator.xml b/Documentation/DocBook/v4l/vidioc-g-modulator.xml new file mode 100644 index 00000000..15ce660f --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-modulator.xml @@ -0,0 +1,246 @@ + + + ioctl VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR + &manvol; + + + + VIDIOC_G_MODULATOR + VIDIOC_S_MODULATOR + Get or set modulator attributes + + + + + + int ioctl + int fd + int request + struct v4l2_modulator +*argp + + + + + int ioctl + int fd + int request + const struct v4l2_modulator +*argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_G_MODULATOR, VIDIOC_S_MODULATOR + + + + argp + + + + + + + + + Description + + To query the attributes of a modulator applications initialize +the index field and zero out the +reserved array of a &v4l2-modulator; and +call the VIDIOC_G_MODULATOR ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the index is out of bounds. To enumerate all modulators +applications shall begin at index zero, incrementing by one until the +driver returns EINVAL. + + Modulators have two writable properties, an audio +modulation set and the radio frequency. To change the modulated audio +subprograms, applications initialize the index + and txsubchans fields and the +reserved array and call the +VIDIOC_S_MODULATOR ioctl. Drivers may choose a +different audio modulation if the request cannot be satisfied. However +this is a write-only ioctl, it does not return the actual audio +modulation selected. + + To change the radio frequency the &VIDIOC-S-FREQUENCY; ioctl +is available. + + + struct <structname>v4l2_modulator</structname> + + &cs-str; + + + __u32 + index + Identifies the modulator, set by the +application. + + + __u8 + name[32] + Name of the modulator, a NUL-terminated ASCII +string. This information is intended for the user. + + + __u32 + capability + Modulator capability flags. No flags are defined +for this field, the tuner flags in &v4l2-tuner; +are used accordingly. The audio flags indicate the ability +to encode audio subprograms. They will not +change for example with the current video standard. + + + __u32 + rangelow + The lowest tunable frequency in units of 62.5 +KHz, or if the capability flag +V4L2_TUNER_CAP_LOW is set, in units of 62.5 +Hz. + + + __u32 + rangehigh + The highest tunable frequency in units of 62.5 +KHz, or if the capability flag +V4L2_TUNER_CAP_LOW is set, in units of 62.5 +Hz. + + + __u32 + txsubchans + With this field applications can determine how +audio sub-carriers shall be modulated. It contains a set of flags as +defined in . Note the tuner +rxsubchans flags are reused, but the +semantics are different. Video output devices are assumed to have an +analog or PCM audio input with 1-3 channels. The +txsubchans flags select one or more +channels for modulation, together with some audio subprogram +indicator, for example a stereo pilot tone. + + + __u32 + reserved[4] + Reserved for future extensions. Drivers and +applications must set the array to zero. + + + +
+ + + Modulator Audio Transmission Flags + + &cs-def; + + + V4L2_TUNER_SUB_MONO + 0x0001 + Modulate channel 1 as mono audio, when the input +has more channels, a down-mix of channel 1 and 2. This flag does not +combine with V4L2_TUNER_SUB_STEREO or +V4L2_TUNER_SUB_LANG1. + + + V4L2_TUNER_SUB_STEREO + 0x0002 + Modulate channel 1 and 2 as left and right +channel of a stereo audio signal. When the input has only one channel +or two channels and V4L2_TUNER_SUB_SAP is also +set, channel 1 is encoded as left and right channel. This flag does +not combine with V4L2_TUNER_SUB_MONO or +V4L2_TUNER_SUB_LANG1. When the driver does not +support stereo audio it shall fall back to mono. + + + V4L2_TUNER_SUB_LANG1 + 0x0008 + Modulate channel 1 and 2 as primary and secondary +language of a bilingual audio signal. When the input has only one +channel it is used for both languages. It is not possible to encode +the primary or secondary language only. This flag does not combine +with V4L2_TUNER_SUB_MONO, +V4L2_TUNER_SUB_STEREO or +V4L2_TUNER_SUB_SAP. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit bilingual audio the +VIDIOC_S_MODULATOR ioctl shall return an &EINVAL; +and the driver shall fall back to mono or stereo mode. + + + V4L2_TUNER_SUB_LANG2 + 0x0004 + Same effect as +V4L2_TUNER_SUB_SAP. + + + V4L2_TUNER_SUB_SAP + 0x0004 + When combined with V4L2_TUNER_SUB_MONO + the first channel is encoded as mono audio, the last +channel as Second Audio Program. When the input has only one channel +it is used for both audio tracks. When the input has three channels +the mono track is a down-mix of channel 1 and 2. When combined with +V4L2_TUNER_SUB_STEREO channel 1 and 2 are +encoded as left and right stereo audio, channel 3 as Second Audio +Program. When the input has only two channels, the first is encoded as +left and right channel and the second as SAP. When the input has only +one channel it is used for all audio tracks. It is not possible to +encode a Second Audio Program only. This flag must combine with +V4L2_TUNER_SUB_MONO or +V4L2_TUNER_SUB_STEREO. If the hardware does not +support the respective audio matrix, or the current video standard +does not permit SAP the VIDIOC_S_MODULATOR ioctl +shall return an &EINVAL; and driver shall fall back to mono or stereo +mode. + + + V4L2_TUNER_SUB_RDS + 0x0010 + Enable the RDS encoder for a radio FM transmitter. + + + +
+ + + + &return-value; + + + + EINVAL + + The &v4l2-modulator; +index is out of bounds. + + + + + + + -- cgit v1.2.3