This system call opens a named video device (e.g. /dev/dvb/adapter0/video0) for subsequent use.

When an open() call has succeeded, the device will be ready for use. The significance of blocking or non-blocking mode is described in the documentation for functions where there is a difference. It does not affect the semantics of the open() call itself. A 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. Only one user can open the Video Device in O_RDWR mode. All other attempts to open the device in this mode will fail, and an error-code will be returned. If the Video Device is opened in O_RDONLY mode, the only ioctl call that can be used is VIDEO_GET_STATUS. All other call will return an error code.

int open(const char ⋆deviceName, int flags);

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)

ENODEV

Device driver not loaded/available.

EINTERNAL

Internal error.

EBUSY

Device or resource busy.

EINVAL

Invalid argument.

This system call closes a previously opened video device.

int close(int fd);

int fd

File descriptor returned by a previous call to open().

EBADF

fd is not a valid open file descriptor.

This system call can only be used if VIDEO_SOURCE_MEMORY is selected in the ioctl call VIDEO_SELECT_SOURCE. The data provided shall be in PES format, unless the capability allows other formats. If O_NONBLOCK is not specified the function will block until buffer space is available. The amount of data to be transferred is implied by count.

size_t write(int fd, const void ⋆buf, size_t count);

int fd

File descriptor returned by a previous call to open().

void *buf

Pointer to the buffer containing the PES data.

size_t count

Size of buf.

EPERM

Mode VIDEO_SOURCE_MEMORY not selected.

ENOMEM

Attempted to write more data than the internal buffer can hold.

EBADF

fd is not a valid open file descriptor.

This ioctl call asks the Video Device to stop playing the current stream. Depending on the input parameter, the screen can be blanked out or displaying the last decoded frame.

int ioctl(fd, int request = VIDEO_STOP, boolean mode);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_STOP for this command.

Boolean mode

Indicates how the screen shall be handled.

TRUE: Blank screen when stop.

FALSE: Show last decoded frame.

This ioctl call asks the Video Device to start playing a video stream from the selected source.

int ioctl(fd, int request = VIDEO_PLAY);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_PLAY for this command.

This ioctl call suspends the live video stream being played. Decoding and playing are frozen. It is then possible to restart the decoding and playing process of the video stream using the VIDEO_CONTINUE command. If VIDEO_SOURCE_MEMORY is selected in the ioctl call VIDEO_SELECT_SOURCE, the DVB subsystem will not decode any more data until the ioctl call VIDEO_CONTINUE or VIDEO_PLAY is performed.

int ioctl(fd, int request = VIDEO_FREEZE);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_FREEZE for this command.

This ioctl call restarts decoding and playing processes of the video stream which was played before a call to VIDEO_FREEZE was made.

int ioctl(fd, int request = VIDEO_CONTINUE);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_CONTINUE for this command.

This ioctl call informs the video device which source shall be used for the input data. The possible sources are demux or memory. If memory is selected, the data is fed to the video device through the write command.

int ioctl(fd, int request = VIDEO_SELECT_SOURCE, video_stream_source_t source);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SELECT_SOURCE for this command.

video_stream_source_t source

Indicates which source shall be used for the Video stream.

This ioctl call asks the Video Device to blank out the picture.

int ioctl(fd, int request = VIDEO_SET_BLANK, boolean mode);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_BLANK for this command.

boolean mode

TRUE: Blank screen when stop.

FALSE: Show last decoded frame.

This ioctl call asks the Video Device to return the current status of the device.

int ioctl(fd, int request = VIDEO_GET_STATUS, struct video_status ⋆status);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_STATUS for this command.

struct video_status *status

Returns the current status of the Video Device.

This ioctl call asks the Video Device to return the number of displayed frames since the decoder was started.

int ioctl(int fd, int request = VIDEO_GET_FRAME_COUNT, __u64 *pts);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_FRAME_COUNT for this command.

__u64 *pts

Returns the number of frames displayed since the decoder was started.

This ioctl call asks the Video Device to return the current PTS timestamp.

int ioctl(int fd, int request = VIDEO_GET_PTS, __u64 *pts);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_PTS for this command.

__u64 *pts

Returns the 33-bit timestamp as defined in ITU T-REC-H.222.0 / ISO/IEC 13818-1.

The PTS should belong to the currently played frame if possible, but may also be a value close to it like the PTS of the last decoded frame or the last PTS extracted by the PES parser.

This ioctl call asks the Video Device to return the current framerate.

int ioctl(int fd, int request = VIDEO_GET_FRAME_RATE, unsigned int *rate);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_FRAME_RATE for this command.

unsigned int *rate

Returns the framerate in number of frames per 1000 seconds.

This ioctl call returns an event of type video_event if available. If an event is not available, the behavior depends on whether the device is in blocking or non-blocking mode. In the latter case, the call fails immediately with errno set to EWOULDBLOCK. In the former case, the call blocks until an event becomes available. The standard Linux poll() and/or select() system calls can be used with the device file descriptor to watch for new events. For select(), the file descriptor should be included in the exceptfds argument, and for poll(), POLLPRI should be specified as the wake-up condition. Read-only permissions are sufficient for this ioctl call.

int ioctl(fd, int request = VIDEO_GET_EVENT, struct video_event ⋆ev);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_EVENT for this command.

struct video_event *ev

Points to the location where the event, if any, is to be stored.

EWOULDBLOCK

There is no event pending, and the device is in non-blocking mode.

EOVERFLOW

Overflow in event queue - one or more events were lost.

This ioctl commands the decoder. The video_command struct is a subset of the v4l2_decoder_cmd struct, so refer to the VIDIOC_DECODER_CMD documentation for more information.

int ioctl(int fd, int request = VIDEO_COMMAND, struct video_command *cmd);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_COMMAND for this command.

struct video_command *cmd

Commands the decoder.

This ioctl tries a decoder command. The video_command struct is a subset of the v4l2_decoder_cmd struct, so refer to the VIDIOC_TRY_DECODER_CMD documentation for more information.

int ioctl(int fd, int request = VIDEO_TRY_COMMAND, struct video_command *cmd);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_TRY_COMMAND for this command.

struct video_command *cmd

Try a decoder command.

This ioctl returns the size and aspect ratio.

int ioctl(int fd, int request = VIDEO_GET_SIZE, video_size_t *size);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_SIZE for this command.

video_size_t *size

Returns the size and aspect ratio.

This ioctl call asks the Video Device to select the video format to be applied by the MPEG chip on the video.

int ioctl(fd, int request = VIDEO_SET_DISPLAY_FORMAT, video_display_format_t format);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_DISPLAY_FORMAT for this command.

video_display_format_t format

Selects the video format to be used.

This ioctl call asks the Video Device to display a still picture (I-frame). The input data shall contain an I-frame. If the pointer is NULL, then the current displayed still picture is blanked.

int ioctl(fd, int request = VIDEO_STILLPICTURE, struct video_still_picture ⋆sp);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_STILLPICTURE for this command.

struct video_still_picture *sp

Pointer to a location where an I-frame and size is stored.

This ioctl call asks the Video Device to skip decoding of N number of I-frames. This call can only be used if VIDEO_SOURCE_MEMORY is selected.

int ioctl(fd, int request = VIDEO_FAST_FORWARD, int nFrames);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_FAST_FORWARD for this command.

int nFrames

The number of frames to skip.

EPERM

Mode VIDEO_SOURCE_MEMORY not selected.

This ioctl call asks the video device to repeat decoding frames N number of times. This call can only be used if VIDEO_SOURCE_MEMORY is selected.

int ioctl(fd, int request = VIDEO_SLOWMOTION, int nFrames);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SLOWMOTION for this command.

int nFrames

The number of times to repeat each frame.

EPERM

Mode VIDEO_SOURCE_MEMORY not selected.

This ioctl call asks the video device about its decoding capabilities. On success it returns and integer which has bits set according to the defines in section ??.

int ioctl(fd, int request = VIDEO_GET_CAPABILITIES, unsigned int ⋆cap);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_CAPABILITIES for this command.

unsigned int *cap

Pointer to a location where to store the capability information.

This ioctl selects which sub-stream is to be decoded if a program or system stream is sent to the video device.

int ioctl(int fd, int request = VIDEO_SET_ID, int id);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_ID for this command.

int id

video sub-stream id

EINVAL

Invalid sub-stream id.

This ioctl call clears all video buffers in the driver and in the decoder hardware.

int ioctl(fd, int request = VIDEO_CLEAR_BUFFER);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_CLEAR_BUFFER for this command.

This ioctl tells the driver which kind of stream to expect being written to it. If this call is not used the default of video PES is used. Some drivers might not support this call and always expect PES.

int ioctl(fd, int request = VIDEO_SET_STREAMTYPE, int type);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_STREAMTYPE for this command.

int type

stream type

This ioctl sets the screen format (aspect ratio) of the connected output device (TV) so that the output of the decoder can be adjusted accordingly.

int ioctl(fd, int request = VIDEO_SET_FORMAT, video_format_t format);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_FORMAT for this command.

video_format_t format

video format of TV as defined in section ??.

EINVAL

format is not a valid video format.

This ioctl sets the television output format. The format (see section ??) may vary from the color format of the displayed MPEG stream. If the hardware is not able to display the requested format the call will return an error.

int ioctl(fd, int request = VIDEO_SET_SYSTEM , video_system_t system);

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_FORMAT for this command.

video_system_t system

video system of TV output.

EINVAL

system is not a valid or supported video system.

This ioctl sets the SPU highlight information for the menu access of a DVD.

int ioctl(fd, int request = VIDEO_SET_HIGHLIGHT ,video_highlight_t ⋆vhilite)

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_HIGHLIGHT for this command.

video_highlight_t *vhilite

SPU Highlight information according to section ??.

This ioctl activates or deactivates SPU decoding in a DVD input stream. It can only be used, if the driver is able to handle a DVD stream.

int ioctl(fd, int request = VIDEO_SET_SPU , video_spu_t ⋆spu)

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_SPU for this command.

video_spu_t *spu

SPU decoding (de)activation and subid setting according to section ??.

EINVAL

input is not a valid spu setting or driver cannot handle SPU.

This ioctl sets the SPU color palette.

int ioctl(fd, int request = VIDEO_SET_SPU_PALETTE ,video_spu_palette_t ⋆palette )

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_SPU_PALETTE for this command.

video_spu_palette_t *palette

SPU palette according to section ??.

EINVAL

input is not a valid palette or driver doesn’t handle SPU.

This ioctl returns navigational information from the DVD stream. This is especially needed if an encoded stream has to be decoded by the hardware.

int ioctl(fd, int request = VIDEO_GET_NAVI , video_navi_pack_t ⋆navipack)

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_GET_NAVI for this command.

video_navi_pack_t *navipack

PCI or DSI pack (private stream 2) according to section ??.

EFAULT

driver is not able to return navigational information

This ioctl is intended for DVD playback and allows you to set certain information about the stream. Some hardware may not need this information, but the call also tells the hardware to prepare for DVD playback.

int ioctl(fd, int request = VIDEO_SET_ATTRIBUTE ,video_attributes_t vattr)

int fd

File descriptor returned by a previous call to open().

int request

Equals VIDEO_SET_ATTRIBUTE for this command.

video_attributes_t vattr

video attributes according to section ??.

EINVAL

input is not a valid attribute setting.