The DVB frontend API was designed to support three types of delivery systems: Terrestrial systems: DVB-T, DVB-T2, ATSC, ATSC M/H, ISDB-T, DVB-H, DTMB, CMMB Cable systems: DVB-C Annex A/C, ClearQAM (DVB-C Annex B), ISDB-C Satellital systems: DVB-S, DVB-S2, DVB Turbo, ISDB-S, DSS The DVB frontend controls several sub-devices including: Tuner, Digital TV demodulator Low noise amplifier (LNA) Satellite Equipment Control (SEC) hardware (only for Satellite). The frontend can be accessed through /dev/dvb/adapter?/frontend?. Data types and ioctl definitions can be accessed by including linux/dvb/frontend.h in your application. NOTE: Transmission via the internet (DVB-IP) is not yet handled by this API but a future extension is possible. On Satellital systems, the API support for the Satellite Equipment Control (SEC) allows to power control and to send/receive signals to control the antenna subsystem, selecting the polarization and choosing the Intermediate Frequency IF) of the Low Noise Block Converter Feed Horn (LNBf). It supports the DiSEqC and V-SEC protocols. The DiSEqC (digital SEC) specification is available at Eutelsat.

Usually, the first thing to do when the frontend is opened is to check the frontend capabilities. This is done using FE_GET_INFO. This ioctl will enumerate the DVB API version and other characteristics about the frontend, and can be opened either in read only or read/write mode.

Once FE_SET_PROPERTY is called, the frontend will run a kernel thread that will periodically check for the tuner lock status and provide statistics about the quality of the signal. The information about the frontend tuner locking status can be queried using FE_READ_STATUS. Signal statistics are provided via FE_GET_PROPERTY. Please notice that several statistics require the demodulator to be fully locked (e. g. with FE_HAS_LOCK bit set). See Frontend statistics indicators for more details.

&sub-dvbproperty;

DESCRIPTION This system call opens a named frontend device (/dev/dvb/adapter0/frontend0) for subsequent use. Usually the first thing to do after a successful open is to find out the frontend type with FE_GET_INFO. The device can be opened in read-only mode, which only allows monitoring of device status and statistics, or read/write mode, which allows any kind of use (e.g. performing tuning operations.) In a system with multiple front-ends, it is usually the case that multiple devices cannot be open in read/write mode simultaneously. As long as a front-end device is opened in read/write mode, other open() calls in read/write mode will either fail or block, depending on whether non-blocking or blocking mode was specified. A front-end device opened in blocking mode can later be put into non-blocking mode (and vice versa) using the F_SETFL command of the fcntl system call. This is a standard system call, documented in the Linux manual page for fcntl. When an open() call has succeeded, the device will be ready for use in the specified mode. This implies that the corresponding hardware is powered up, and that other front-ends may have been powered down to make that possible. SYNOPSIS int open(const char ⋆deviceName, int flags); PARAMETERS const char *deviceName Name of specific video device. int flags A bit-wise OR of the following flags: O_RDONLY read-only access O_RDWR read/write access O_NONBLOCK open in non-blocking mode (blocking mode is the default) RETURN VALUE ENODEV Device driver not loaded/available. EINTERNAL Internal error. EBUSY Device or resource busy. EINVAL Invalid argument.

DESCRIPTION This system call closes a previously opened front-end device. After closing a front-end device, its corresponding hardware might be powered down automatically. SYNOPSIS int close(int fd); PARAMETERS int fd File descriptor returned by a previous call to open(). RETURN VALUE EBADF fd is not a valid open file descriptor.

&sub-fe-get-info; &sub-fe-read-status; &sub-fe-get-property; &sub-fe-diseqc-reset-overload; &sub-fe-diseqc-send-master-cmd; &sub-fe-diseqc-recv-slave-reply; &sub-fe-diseqc-send-burst; &sub-fe-set-tone; &sub-fe-set-voltage; &sub-fe-enable-high-lnb-voltage; &sub-fe-set-frontend-tune-mode;

The usage of this API is deprecated, as it doesn't support all digital TV standards, doesn't provide good statistics measurements and provides incomplete information. This is kept only to support legacy applications. &sub-frontend_legacy_api;