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v4l2.c File Reference

Video4Linux2 grab interface. More...

#include <stdatomic.h>
#include "v4l2-common.h"
#include <dirent.h>

Go to the source code of this file.

Data Structures

struct  video_data
 
struct  buff_data
 

Macros

#define V4L_ALLFORMATS   3
 
#define V4L_RAWFORMATS   1
 
#define V4L_COMPFORMATS   2
 
#define V4L_TS_DEFAULT   0
 Return timestamps to the user exactly as returned by the kernel. More...
 
#define V4L_TS_ABS   1
 Autodetect the kind of timestamps returned by the kernel and convert to absolute (wall clock) timestamps. More...
 
#define V4L_TS_MONO2ABS   2
 Assume kernel timestamps are from the monotonic clock and convert to absolute timestamps. More...
 
#define V4L_TS_CONVERT_READY   V4L_TS_DEFAULT
 Once the kind of timestamps returned by the kernel have been detected, the value of the timefilter (NULL or not) determines whether a conversion takes place. More...
 
#define SET_WRAPPERS(prefix)
 
#define v4l2_open   s->open_f
 
#define v4l2_close   s->close_f
 
#define v4l2_dup   s->dup_f
 
#define v4l2_ioctl   s->ioctl_f
 
#define v4l2_read   s->read_f
 
#define v4l2_mmap   s->mmap_f
 
#define v4l2_munmap   s->munmap_f
 
#define OFFSET(x)   offsetof(struct video_data, x)
 
#define DEC   AV_OPT_FLAG_DECODING_PARAM
 

Functions

static int device_open (AVFormatContext *ctx, const char *device_path)
 
static int device_init (AVFormatContext *ctx, int *width, int *height, uint32_t pixelformat)
 
static int first_field (const struct video_data *s)
 
static void list_formats (AVFormatContext *ctx, int type)
 
static void list_standards (AVFormatContext *ctx)
 
static int mmap_init (AVFormatContext *ctx)
 
static int enqueue_buffer (struct video_data *s, struct v4l2_buffer *buf)
 
static void mmap_release_buffer (void *opaque, uint8_t *data)
 
static int init_convert_timestamp (AVFormatContext *ctx, int64_t ts)
 
static int convert_timestamp (AVFormatContext *ctx, int64_t *ts)
 
static int mmap_read_frame (AVFormatContext *ctx, AVPacket *pkt)
 
static int mmap_start (AVFormatContext *ctx)
 
static void mmap_close (struct video_data *s)
 
static int v4l2_set_parameters (AVFormatContext *ctx)
 
static int device_try_init (AVFormatContext *ctx, enum AVPixelFormat pix_fmt, int *width, int *height, uint32_t *desired_format, enum AVCodecID *codec_id)
 
static int v4l2_read_probe (AVProbeData *p)
 
static int v4l2_read_header (AVFormatContext *ctx)
 
static int v4l2_read_packet (AVFormatContext *ctx, AVPacket *pkt)
 
static int v4l2_read_close (AVFormatContext *ctx)
 
static int v4l2_is_v4l_dev (const char *name)
 
static int v4l2_get_device_list (AVFormatContext *ctx, AVDeviceInfoList *device_list)
 

Variables

static const int desired_video_buffers = 256
 
static const AVOption options []
 
static const AVClass v4l2_class
 
AVInputFormat ff_v4l2_demuxer
 

Detailed Description

Video4Linux2 grab interface.

Part of this file is based on the V4L2 video capture example (http://linuxtv.org/downloads/v4l-dvb-apis/capture-example.html)

Thanks to Michael Niedermayer for providing the mapping between V4L2_PIX_FMT_* and AV_PIX_FMT_*

Definition in file v4l2.c.

Macro Definition Documentation

#define V4L_ALLFORMATS   3

Definition at line 44 of file v4l2.c.

#define V4L_RAWFORMATS   1

Definition at line 45 of file v4l2.c.

Referenced by list_formats().

#define V4L_COMPFORMATS   2

Definition at line 46 of file v4l2.c.

Referenced by list_formats().

#define V4L_TS_DEFAULT   0

Return timestamps to the user exactly as returned by the kernel.

Definition at line 51 of file v4l2.c.

#define V4L_TS_ABS   1

Autodetect the kind of timestamps returned by the kernel and convert to absolute (wall clock) timestamps.

Definition at line 56 of file v4l2.c.

Referenced by init_convert_timestamp().

#define V4L_TS_MONO2ABS   2

Assume kernel timestamps are from the monotonic clock and convert to absolute timestamps.

Definition at line 61 of file v4l2.c.

Referenced by init_convert_timestamp().

#define V4L_TS_CONVERT_READY   V4L_TS_DEFAULT

Once the kind of timestamps returned by the kernel have been detected, the value of the timefilter (NULL or not) determines whether a conversion takes place.

Definition at line 68 of file v4l2.c.

Referenced by init_convert_timestamp().

#define SET_WRAPPERS (   prefix)
Value:
do { \
s->open_f = prefix ## open; \
s->close_f = prefix ## close; \
s->dup_f = prefix ## dup; \
s->ioctl_f = prefix ## ioctl; \
s->read_f = prefix ## read; \
s->mmap_f = prefix ## mmap; \
s->munmap_f = prefix ## munmap; \
} while (0)
s
#define s(width, name)
Definition: cbs_vp9.c:257

Referenced by device_open().

#define v4l2_open   s->open_f

Referenced by device_open().

#define v4l2_close   s->close_f

Referenced by device_open(), v4l2_get_device_list(), v4l2_read_close(), and v4l2_read_header().

#define v4l2_dup   s->dup_f
#define v4l2_ioctl   s->ioctl_f

Referenced by device_init(), device_open(), enqueue_buffer(), first_field(), list_formats(), list_standards(), mmap_close(), mmap_init(), mmap_read_frame(), mmap_start(), v4l2_get_device_list(), v4l2_read_header(), and v4l2_set_parameters().

#define v4l2_read   s->read_f
#define v4l2_mmap   s->mmap_f

Referenced by mmap_init().

#define v4l2_munmap   s->munmap_f

Referenced by mmap_close().

#define OFFSET (   x)    offsetof(struct video_data, x)

Definition at line 1095 of file v4l2.c.

#define DEC   AV_OPT_FLAG_DECODING_PARAM

Definition at line 1096 of file v4l2.c.

Function Documentation

static int device_open ( AVFormatContext *  ctx,
const char *  device_path 
)
static

Definition at line 109 of file v4l2.c.

Referenced by v4l2_get_device_list(), and v4l2_read_header().

static int device_init ( AVFormatContext *  ctx,
int *  width,
int *  height,
uint32_t  pixelformat 
)
static

Definition at line 188 of file v4l2.c.

Referenced by device_try_init().

static int first_field ( const struct video_data *  s)
static

Definition at line 230 of file v4l2.c.

Referenced by dnxhd_decode_frame(), dnxhd_encode_picture(), and v4l2_read_header().

static void list_formats ( AVFormatContext *  ctx,
int  type 
)
static

Definition at line 271 of file v4l2.c.

Referenced by v4l2_read_header().

static void list_standards ( AVFormatContext *  ctx)
static

Definition at line 309 of file v4l2.c.

Referenced by v4l2_read_header().

static int mmap_init ( AVFormatContext *  ctx)
static

Definition at line 333 of file v4l2.c.

Referenced by v4l2_read_header().

static int enqueue_buffer ( struct video_data *  s,
struct v4l2_buffer *  buf 
)
static

Definition at line 399 of file v4l2.c.

Referenced by mmap_read_frame(), and mmap_release_buffer().

static void mmap_release_buffer ( void *  opaque,
uint8_t *  data 
)
static

Definition at line 413 of file v4l2.c.

Referenced by mmap_read_frame().

static int init_convert_timestamp ( AVFormatContext *  ctx,
int64_t  ts 
)
static

Definition at line 434 of file v4l2.c.

Referenced by convert_timestamp().

static int convert_timestamp ( AVFormatContext *  ctx,
int64_t *  ts 
)
static

Definition at line 467 of file v4l2.c.

Referenced by mmap_read_frame().

static int mmap_read_frame ( AVFormatContext *  ctx,
AVPacket *  pkt 
)
static

Definition at line 488 of file v4l2.c.

Referenced by v4l2_read_packet().

static int mmap_start ( AVFormatContext *  ctx)
static

Definition at line 595 of file v4l2.c.

Referenced by v4l2_read_header().

static void mmap_close ( struct video_data *  s)
static

Definition at line 628 of file v4l2.c.

Referenced by v4l2_read_close().

static int v4l2_set_parameters ( AVFormatContext *  ctx)
static

Definition at line 645 of file v4l2.c.

Referenced by v4l2_read_header().

static int device_try_init ( AVFormatContext *  ctx,
enum AVPixelFormat  pix_fmt,
int *  width,
int *  height,
uint32_t *  desired_format,
enum AVCodecID *  codec_id 
)
static

Definition at line 763 of file v4l2.c.

Referenced by v4l2_read_header().

static int v4l2_read_probe ( AVProbeData *  p)
static

Definition at line 815 of file v4l2.c.

static int v4l2_read_header ( AVFormatContext *  ctx)
static

Definition at line 822 of file v4l2.c.

static int v4l2_read_packet ( AVFormatContext *  ctx,
AVPacket *  pkt 
)
static

Definition at line 978 of file v4l2.c.

static int v4l2_read_close ( AVFormatContext *  ctx)
static

Definition at line 1004 of file v4l2.c.

static int v4l2_is_v4l_dev ( const char *  name)
static

Definition at line 1018 of file v4l2.c.

Referenced by v4l2_get_device_list().

static int v4l2_get_device_list ( AVFormatContext *  ctx,
AVDeviceInfoList *  device_list 
)
static

Definition at line 1026 of file v4l2.c.

Variable Documentation

const int desired_video_buffers = 256
static

Definition at line 42 of file v4l2.c.

Referenced by mmap_init().

const AVOption options[]
static
Initial value:
= {
{ "standard", "set TV standard, used only by analog frame grabber", OFFSET(standard), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, DEC },
{ "channel", "set TV channel, used only by frame grabber", OFFSET(channel), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, INT_MAX, DEC },
{ "video_size", "set frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
{ "pixel_format", "set preferred pixel format", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
{ "input_format", "set preferred pixel format (for raw video) or codec name", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
{ "framerate", "set frame rate", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
{ "list_formats", "list available formats and exit", OFFSET(list_format), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, DEC, "list_formats" },
{ "all", "show all available formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_ALLFORMATS }, 0, INT_MAX, DEC, "list_formats" },
{ "raw", "show only non-compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_RAWFORMATS }, 0, INT_MAX, DEC, "list_formats" },
{ "compressed", "show only compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_COMPFORMATS }, 0, INT_MAX, DEC, "list_formats" },
{ "list_standards", "list supported standards and exit", OFFSET(list_standard), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, DEC, "list_standards" },
{ "all", "show all supported standards", OFFSET(list_standard), AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, DEC, "list_standards" },
{ "timestamps", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },
{ "ts", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },
{ "default", "use timestamps from the kernel", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_DEFAULT }, 0, 2, DEC, "timestamps" },
{ "abs", "use absolute timestamps (wall clock)", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_ABS }, 0, 2, DEC, "timestamps" },
{ "mono2abs", "force conversion from monotonic to absolute timestamps", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_MONO2ABS }, 0, 2, DEC, "timestamps" },
{ "use_libv4l2", "use libv4l2 (v4l-utils) conversion functions", OFFSET(use_libv4l2), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DEC },
{ NULL },
}
NULL
#define NULL
Definition: coverity.c:32
AV_OPT_TYPE_INT
Definition: opt.h:223
AV_OPT_TYPE_CONST
Definition: opt.h:232
V4L_TS_ABS
#define V4L_TS_ABS
Autodetect the kind of timestamps returned by the kernel and convert to absolute (wall clock) timesta...
Definition: v4l2.c:56
AV_OPT_TYPE_STRING
Definition: opt.h:227
V4L_TS_DEFAULT
#define V4L_TS_DEFAULT
Return timestamps to the user exactly as returned by the kernel.
Definition: v4l2.c:51
OFFSET
#define OFFSET(x)
Definition: v4l2.c:1095
V4L_TS_MONO2ABS
#define V4L_TS_MONO2ABS
Assume kernel timestamps are from the monotonic clock and convert to absolute timestamps.
Definition: v4l2.c:61
width
#define width
AV_OPT_TYPE_BOOL
Definition: opt.h:240
V4L_ALLFORMATS
#define V4L_ALLFORMATS
Definition: v4l2.c:44
AV_OPT_TYPE_IMAGE_SIZE
offset must point to two consecutive integers
Definition: opt.h:233
V4L_COMPFORMATS
#define V4L_COMPFORMATS
Definition: v4l2.c:46
channel
channel
Use these values when setting the channel map with ebur128_set_channel().
Definition: ebur128.h:39
V4L_RAWFORMATS
#define V4L_RAWFORMATS
Definition: v4l2.c:45
DEC
#define DEC
Definition: v4l2.c:1096

Definition at line 1098 of file v4l2.c.

const AVClass v4l2_class
static
Initial value:
= {
.class_name = "V4L2 indev",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
.category = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
}
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
options
static const AVOption options[]
Definition: v4l2.c:1098

Definition at line 1123 of file v4l2.c.

AVInputFormat ff_v4l2_demuxer
Initial value:
= {
.name = "video4linux2,v4l2",
.long_name = NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"),
.priv_data_size = sizeof(struct video_data),
.read_probe = v4l2_read_probe,
.read_header = v4l2_read_header,
.read_packet = v4l2_read_packet,
.read_close = v4l2_read_close,
.get_device_list = v4l2_get_device_list,
.flags = AVFMT_NOFILE,
.priv_class = &v4l2_class,
}
v4l2_read_header
static int v4l2_read_header(AVFormatContext *ctx)
Definition: v4l2.c:822
v4l2_get_device_list
static int v4l2_get_device_list(AVFormatContext *ctx, AVDeviceInfoList *device_list)
Definition: v4l2.c:1026
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
video_data
Definition: v4l2.c:70
read_probe
static int read_probe(AVProbeData *pd)
Definition: jvdec.c:55
v4l2_read_close
static int v4l2_read_close(AVFormatContext *ctx)
Definition: v4l2.c:1004
v4l2_class
static const AVClass v4l2_class
Definition: v4l2.c:1123
v4l2_read_packet
static int v4l2_read_packet(AVFormatContext *ctx, AVPacket *pkt)
Definition: v4l2.c:978
AVFMT_NOFILE
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:465
v4l2_read_probe
static int v4l2_read_probe(AVProbeData *p)
Definition: v4l2.c:815

Definition at line 1131 of file v4l2.c.

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