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librempeg/libavdevice/v4l2.c
Anton Khirnov 877b6a9e82 lavd/v4l2: detect device name truncation 
Silences the following warning with gcc 10:
src/libavdevice/v4l2.c: In function ‘v4l2_get_device_list’:
src/libavdevice/v4l2.c:1042:64: warning: ‘%s’ directive output may be truncated writing up to 255 bytes into a region of size 251 [-Wformat-truncation=]
 1042 |         ret = snprintf(device_name, sizeof(device_name), "/dev/%s", entry->d_name);
      |                                                                ^~
src/libavdevice/v4l2.c:1042:15: note: ‘snprintf’ output between 6 and 261 bytes into a destination of size 256
 1042 |         ret = snprintf(device_name, sizeof(device_name), "/dev/%s", entry->d_name);
      |               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Previous patches intending to silence it have proposed increasing the
buffer size, but doing that correctly seems to be tricky. Failing on
truncation is simpler and just as effective (as excessively long device
names are unlikely).
2021-12-07 11:16:14 +01:00

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/*
* Copyright (c) 2000,2001 Fabrice Bellard
* Copyright (c) 2006 Luca Abeni
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* 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_*
*/
#include <stdatomic.h>
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "v4l2-common.h"
#include <dirent.h>
#if CONFIG_LIBV4L2
#include <libv4l2.h>
#endif
static const int desired_video_buffers = 256;
#define V4L_ALLFORMATS 3
#define V4L_RAWFORMATS 1
#define V4L_COMPFORMATS 2
/**
* Return timestamps to the user exactly as returned by the kernel
*/
#define V4L_TS_DEFAULT 0
/**
* Autodetect the kind of timestamps returned by the kernel and convert to
* absolute (wall clock) timestamps.
*/
#define V4L_TS_ABS 1
/**
* Assume kernel timestamps are from the monotonic clock and convert to
* absolute timestamps.
*/
#define V4L_TS_MONO2ABS 2
/**
* 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.
*/
#define V4L_TS_CONVERT_READY V4L_TS_DEFAULT
struct video_data {
AVClass *class;
int fd;
int pixelformat; /* V4L2_PIX_FMT_* */
int width, height;
int frame_size;
int interlaced;
int top_field_first;
int ts_mode;
TimeFilter *timefilter;
int64_t last_time_m;
int buffers;
atomic_int buffers_queued;
void **buf_start;
unsigned int *buf_len;
char *standard;
v4l2_std_id std_id;
int channel;
char *pixel_format; /**< Set by a private option. */
int list_format; /**< Set by a private option. */
int list_standard; /**< Set by a private option. */
char *framerate; /**< Set by a private option. */
int use_libv4l2;
int (*open_f)(const char *file, int oflag, ...);
int (*close_f)(int fd);
int (*dup_f)(int fd);
#ifdef __GLIBC__
int (*ioctl_f)(int fd, unsigned long int request, ...);
#else
int (*ioctl_f)(int fd, int request, ...);
#endif
ssize_t (*read_f)(int fd, void *buffer, size_t n);
void *(*mmap_f)(void *start, size_t length, int prot, int flags, int fd, int64_t offset);
int (*munmap_f)(void *_start, size_t length);
};
struct buff_data {
struct video_data *s;
int index;
};
static int device_open(AVFormatContext *ctx, const char* device_path)
{
struct video_data *s = ctx->priv_data;
struct v4l2_capability cap;
int fd;
int err;
int flags = O_RDWR;
#define SET_WRAPPERS(prefix) 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)
if (s->use_libv4l2) {
#if CONFIG_LIBV4L2
SET_WRAPPERS(v4l2_);
#else
av_log(ctx, AV_LOG_ERROR, "libavdevice is not built with libv4l2 support.\n");
return AVERROR(EINVAL);
#endif
} else {
SET_WRAPPERS();
}
#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
if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
flags |= O_NONBLOCK;
}
fd = v4l2_open(device_path, flags, 0);
if (fd < 0) {
err = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s: %s\n",
device_path, av_err2str(err));
return err;
}
if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
err = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
av_err2str(err));
goto fail;
}
av_log(ctx, AV_LOG_VERBOSE, "fd:%d capabilities:%x\n",
fd, cap.capabilities);
if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
av_log(ctx, AV_LOG_ERROR, "Not a video capture device.\n");
err = AVERROR(ENODEV);
goto fail;
}
if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
av_log(ctx, AV_LOG_ERROR,
"The device does not support the streaming I/O method.\n");
err = AVERROR(ENOSYS);
goto fail;
}
return fd;
fail:
v4l2_close(fd);
return err;
}
static int device_init(AVFormatContext *ctx, int *width, int *height,
uint32_t pixelformat)
{
struct video_data *s = ctx->priv_data;
struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
int res = 0;
fmt.fmt.pix.width = *width;
fmt.fmt.pix.height = *height;
fmt.fmt.pix.pixelformat = pixelformat;
fmt.fmt.pix.field = V4L2_FIELD_ANY;
/* Some drivers will fail and return EINVAL when the pixelformat
is not supported (even if type field is valid and supported) */
if (v4l2_ioctl(s->fd, VIDIOC_S_FMT, &fmt) < 0)
res = AVERROR(errno);
if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) {
av_log(ctx, AV_LOG_INFO,
"The V4L2 driver changed the video from %dx%d to %dx%d\n",
*width, *height, fmt.fmt.pix.width, fmt.fmt.pix.height);
*width = fmt.fmt.pix.width;
*height = fmt.fmt.pix.height;
}
if (pixelformat != fmt.fmt.pix.pixelformat) {
av_log(ctx, AV_LOG_DEBUG,
"The V4L2 driver changed the pixel format "
"from 0x%08X to 0x%08X\n",
pixelformat, fmt.fmt.pix.pixelformat);
res = AVERROR(EINVAL);
}
if (fmt.fmt.pix.field == V4L2_FIELD_INTERLACED) {
av_log(ctx, AV_LOG_DEBUG,
"The V4L2 driver is using the interlaced mode\n");
s->interlaced = 1;
}
return res;
}
static int first_field(const struct video_data *s)
{
int res;
v4l2_std_id std;
res = v4l2_ioctl(s->fd, VIDIOC_G_STD, &std);
if (res < 0)
return 0;
if (std & V4L2_STD_NTSC)
return 0;
return 1;
}
#if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
static void list_framesizes(AVFormatContext *ctx, uint32_t pixelformat)
{
const struct video_data *s = ctx->priv_data;
struct v4l2_frmsizeenum vfse = { .pixel_format = pixelformat };
while(!v4l2_ioctl(s->fd, VIDIOC_ENUM_FRAMESIZES, &vfse)) {
switch (vfse.type) {
case V4L2_FRMSIZE_TYPE_DISCRETE:
av_log(ctx, AV_LOG_INFO, " %ux%u",
vfse.discrete.width, vfse.discrete.height);
break;
case V4L2_FRMSIZE_TYPE_CONTINUOUS:
case V4L2_FRMSIZE_TYPE_STEPWISE:
av_log(ctx, AV_LOG_INFO, " {%u-%u, %u}x{%u-%u, %u}",
vfse.stepwise.min_width,
vfse.stepwise.max_width,
vfse.stepwise.step_width,
vfse.stepwise.min_height,
vfse.stepwise.max_height,
vfse.stepwise.step_height);
}
vfse.index++;
}
}
#endif
static void list_formats(AVFormatContext *ctx, int type)
{
const struct video_data *s = ctx->priv_data;
struct v4l2_fmtdesc vfd = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
while(!v4l2_ioctl(s->fd, VIDIOC_ENUM_FMT, &vfd)) {
enum AVCodecID codec_id = ff_fmt_v4l2codec(vfd.pixelformat);
enum AVPixelFormat pix_fmt = ff_fmt_v4l2ff(vfd.pixelformat, codec_id);
vfd.index++;
if (!(vfd.flags & V4L2_FMT_FLAG_COMPRESSED) &&
type & V4L_RAWFORMATS) {
const char *fmt_name = av_get_pix_fmt_name(pix_fmt);
av_log(ctx, AV_LOG_INFO, "Raw : %11s : %20s :",
fmt_name ? fmt_name : "Unsupported",
vfd.description);
} else if (vfd.flags & V4L2_FMT_FLAG_COMPRESSED &&
type & V4L_COMPFORMATS) {
const AVCodecDescriptor *desc = avcodec_descriptor_get(codec_id);
av_log(ctx, AV_LOG_INFO, "Compressed: %11s : %20s :",
desc ? desc->name : "Unsupported",
vfd.description);
} else {
continue;
}
#ifdef V4L2_FMT_FLAG_EMULATED
if (vfd.flags & V4L2_FMT_FLAG_EMULATED)
av_log(ctx, AV_LOG_INFO, " Emulated :");
#endif
#if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
list_framesizes(ctx, vfd.pixelformat);
#endif
av_log(ctx, AV_LOG_INFO, "\n");
}
}
static void list_standards(AVFormatContext *ctx)
{
int ret;
struct video_data *s = ctx->priv_data;
struct v4l2_standard standard;
if (s->std_id == 0)
return;
for (standard.index = 0; ; standard.index++) {
if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
ret = AVERROR(errno);
if (ret == AVERROR(EINVAL)) {
break;
} else {
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
return;
}
}
av_log(ctx, AV_LOG_INFO, "%2d, %16"PRIx64", %s\n",
standard.index, (uint64_t)standard.id, standard.name);
}
}
static int mmap_init(AVFormatContext *ctx)
{
int i, res;
struct video_data *s = ctx->priv_data;
struct v4l2_requestbuffers req = {
.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
.count = desired_video_buffers,
.memory = V4L2_MEMORY_MMAP
};
if (v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS): %s\n", av_err2str(res));
return res;
}
if (req.count < 2) {
av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n");
return AVERROR(ENOMEM);
}
s->buffers = req.count;
s->buf_start = av_malloc_array(s->buffers, sizeof(void *));
if (!s->buf_start) {
av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer pointers\n");
return AVERROR(ENOMEM);
}
s->buf_len = av_malloc_array(s->buffers, sizeof(unsigned int));
if (!s->buf_len) {
av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer sizes\n");
av_freep(&s->buf_start);
return AVERROR(ENOMEM);
}
for (i = 0; i < req.count; i++) {
struct v4l2_buffer buf = {
.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
.index = i,
.memory = V4L2_MEMORY_MMAP
};
if (v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF): %s\n", av_err2str(res));
return res;
}
s->buf_len[i] = buf.length;
if (s->frame_size > 0 && s->buf_len[i] < s->frame_size) {
av_log(ctx, AV_LOG_ERROR,
"buf_len[%d] = %d < expected frame size %d\n",
i, s->buf_len[i], s->frame_size);
return AVERROR(ENOMEM);
}
s->buf_start[i] = v4l2_mmap(NULL, buf.length,
PROT_READ | PROT_WRITE, MAP_SHARED,
s->fd, buf.m.offset);
if (s->buf_start[i] == MAP_FAILED) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", av_err2str(res));
return res;
}
}
return 0;
}
static int enqueue_buffer(struct video_data *s, struct v4l2_buffer *buf)
{
int res = 0;
if (v4l2_ioctl(s->fd, VIDIOC_QBUF, buf) < 0) {
res = AVERROR(errno);
av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));
} else {
atomic_fetch_add(&s->buffers_queued, 1);
}
return res;
}
static void mmap_release_buffer(void *opaque, uint8_t *data)
{
struct v4l2_buffer buf = { 0 };
struct buff_data *buf_descriptor = opaque;
struct video_data *s = buf_descriptor->s;
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = buf_descriptor->index;
av_free(buf_descriptor);
enqueue_buffer(s, &buf);
}
#if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
static int64_t av_gettime_monotonic(void)
{
return av_gettime_relative();
}
#endif
static int init_convert_timestamp(AVFormatContext *ctx, int64_t ts)
{
struct video_data *s = ctx->priv_data;
int64_t now;
now = av_gettime();
if (s->ts_mode == V4L_TS_ABS &&
ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE) {
av_log(ctx, AV_LOG_INFO, "Detected absolute timestamps\n");
s->ts_mode = V4L_TS_CONVERT_READY;
return 0;
}
#if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
if (ctx->streams[0]->avg_frame_rate.num) {
now = av_gettime_monotonic();
if (s->ts_mode == V4L_TS_MONO2ABS ||
(ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE)) {
AVRational tb = {AV_TIME_BASE, 1};
int64_t period = av_rescale_q(1, tb, ctx->streams[0]->avg_frame_rate);
av_log(ctx, AV_LOG_INFO, "Detected monotonic timestamps, converting\n");
/* microseconds instead of seconds, MHz instead of Hz */
s->timefilter = ff_timefilter_new(1, period, 1.0E-6);
if (!s->timefilter)
return AVERROR(ENOMEM);
s->ts_mode = V4L_TS_CONVERT_READY;
return 0;
}
}
#endif
av_log(ctx, AV_LOG_ERROR, "Unknown timestamps\n");
return AVERROR(EIO);
}
static int convert_timestamp(AVFormatContext *ctx, int64_t *ts)
{
struct video_data *s = ctx->priv_data;
if (s->ts_mode) {
int r = init_convert_timestamp(ctx, *ts);
if (r < 0)
return r;
}
#if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
if (s->timefilter) {
int64_t nowa = av_gettime();
int64_t nowm = av_gettime_monotonic();
ff_timefilter_update(s->timefilter, nowa, nowm - s->last_time_m);
s->last_time_m = nowm;
*ts = ff_timefilter_eval(s->timefilter, *ts - nowm);
}
#endif
return 0;
}
static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
{
struct video_data *s = ctx->priv_data;
struct v4l2_buffer buf = {
.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
.memory = V4L2_MEMORY_MMAP
};
struct timeval buf_ts;
int res;
pkt->size = 0;
/* FIXME: Some special treatment might be needed in case of loss of signal... */
while ((res = v4l2_ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
if (res < 0) {
if (errno == EAGAIN)
return AVERROR(EAGAIN);
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n",
av_err2str(res));
return res;
}
buf_ts = buf.timestamp;
if (buf.index >= s->buffers) {
av_log(ctx, AV_LOG_ERROR, "Invalid buffer index received.\n");
return AVERROR(EINVAL);
}
atomic_fetch_add(&s->buffers_queued, -1);
// always keep at least one buffer queued
av_assert0(atomic_load(&s->buffers_queued) >= 1);
#ifdef V4L2_BUF_FLAG_ERROR
if (buf.flags & V4L2_BUF_FLAG_ERROR) {
av_log(ctx, AV_LOG_WARNING,
"Dequeued v4l2 buffer contains corrupted data (%d bytes).\n",
buf.bytesused);
buf.bytesused = 0;
} else
#endif
{
/* CPIA is a compressed format and we don't know the exact number of bytes
* used by a frame, so set it here as the driver announces it. */
if (ctx->video_codec_id == AV_CODEC_ID_CPIA)
s->frame_size = buf.bytesused;
if (s->frame_size > 0 && buf.bytesused != s->frame_size) {
av_log(ctx, AV_LOG_WARNING,
"Dequeued v4l2 buffer contains %d bytes, but %d were expected. Flags: 0x%08X.\n",
buf.bytesused, s->frame_size, buf.flags);
buf.bytesused = 0;
}
}
/* Image is at s->buff_start[buf.index] */
if (atomic_load(&s->buffers_queued) == FFMAX(s->buffers / 8, 1)) {
/* when we start getting low on queued buffers, fall back on copying data */
res = av_new_packet(pkt, buf.bytesused);
if (res < 0) {
av_log(ctx, AV_LOG_ERROR, "Error allocating a packet.\n");
enqueue_buffer(s, &buf);
return res;
}
memcpy(pkt->data, s->buf_start[buf.index], buf.bytesused);
res = enqueue_buffer(s, &buf);
if (res) {
av_packet_unref(pkt);
return res;
}
} else {
struct buff_data *buf_descriptor;
pkt->data = s->buf_start[buf.index];
pkt->size = buf.bytesused;
buf_descriptor = av_malloc(sizeof(struct buff_data));
if (!buf_descriptor) {
/* Something went wrong... Since av_malloc() failed, we cannot even
* allocate a buffer for memcpying into it
*/
av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");
enqueue_buffer(s, &buf);
return AVERROR(ENOMEM);
}
buf_descriptor->index = buf.index;
buf_descriptor->s = s;
pkt->buf = av_buffer_create(pkt->data, pkt->size, mmap_release_buffer,
buf_descriptor, 0);
if (!pkt->buf) {
av_log(ctx, AV_LOG_ERROR, "Failed to create a buffer\n");
enqueue_buffer(s, &buf);
av_freep(&buf_descriptor);
return AVERROR(ENOMEM);
}
}
pkt->pts = buf_ts.tv_sec * INT64_C(1000000) + buf_ts.tv_usec;
convert_timestamp(ctx, &pkt->pts);
return pkt->size;
}
static int mmap_start(AVFormatContext *ctx)
{
struct video_data *s = ctx->priv_data;
enum v4l2_buf_type type;
int i, res;
for (i = 0; i < s->buffers; i++) {
struct v4l2_buffer buf = {
.type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
.index = i,
.memory = V4L2_MEMORY_MMAP
};
if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
av_err2str(res));
return res;
}
}
atomic_store(&s->buffers_queued, s->buffers);
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n",
av_err2str(res));
return res;
}
return 0;
}
static void mmap_close(struct video_data *s)
{
enum v4l2_buf_type type;
int i;
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
/* We do not check for the result, because we could
* not do anything about it anyway...
*/
v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);
for (i = 0; i < s->buffers; i++) {
v4l2_munmap(s->buf_start[i], s->buf_len[i]);
}
av_freep(&s->buf_start);
av_freep(&s->buf_len);
}
static int v4l2_set_parameters(AVFormatContext *ctx)
{
struct video_data *s = ctx->priv_data;
struct v4l2_standard standard = { 0 };
struct v4l2_streamparm streamparm = { 0 };
struct v4l2_fract *tpf;
AVRational framerate_q = { 0 };
int i, ret;
if (s->framerate &&
(ret = av_parse_video_rate(&framerate_q, s->framerate)) < 0) {
av_log(ctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n",
s->framerate);
return ret;
}
if (s->standard) {
if (s->std_id) {
ret = 0;
av_log(ctx, AV_LOG_DEBUG, "Setting standard: %s\n", s->standard);
/* set tv standard */
for (i = 0; ; i++) {
standard.index = i;
if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
ret = AVERROR(errno);
break;
}
if (!av_strcasecmp(standard.name, s->standard))
break;
}
if (ret < 0) {
av_log(ctx, AV_LOG_ERROR, "Unknown or unsupported standard '%s'\n", s->standard);
return ret;
}
if (v4l2_ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
ret = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_STD): %s\n", av_err2str(ret));
return ret;
}
} else {
av_log(ctx, AV_LOG_WARNING,
"This device does not support any standard\n");
}
}
/* get standard */
if (v4l2_ioctl(s->fd, VIDIOC_G_STD, &s->std_id) == 0) {
tpf = &standard.frameperiod;
for (i = 0; ; i++) {
standard.index = i;
if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
ret = AVERROR(errno);
if (ret == AVERROR(EINVAL)
#ifdef ENODATA
|| ret == AVERROR(ENODATA)
#endif
) {
tpf = &streamparm.parm.capture.timeperframe;
break;
}
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
return ret;
}
if (standard.id == s->std_id) {
av_log(ctx, AV_LOG_DEBUG,
"Current standard: %s, id: %"PRIx64", frameperiod: %d/%d\n",
standard.name, (uint64_t)standard.id, tpf->numerator, tpf->denominator);
break;
}
}
} else {
tpf = &streamparm.parm.capture.timeperframe;
}
streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (v4l2_ioctl(s->fd, VIDIOC_G_PARM, &streamparm) < 0) {
ret = AVERROR(errno);
av_log(ctx, AV_LOG_WARNING, "ioctl(VIDIOC_G_PARM): %s\n", av_err2str(ret));
} else if (framerate_q.num && framerate_q.den) {
if (streamparm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME) {
tpf = &streamparm.parm.capture.timeperframe;
av_log(ctx, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",
framerate_q.den, framerate_q.num);
tpf->numerator = framerate_q.den;
tpf->denominator = framerate_q.num;
if (v4l2_ioctl(s->fd, VIDIOC_S_PARM, &streamparm) < 0) {
ret = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_PARM): %s\n",
av_err2str(ret));
return ret;
}
if (framerate_q.num != tpf->denominator ||
framerate_q.den != tpf->numerator) {
av_log(ctx, AV_LOG_INFO,
"The driver changed the time per frame from "
"%d/%d to %d/%d\n",
framerate_q.den, framerate_q.num,
tpf->numerator, tpf->denominator);
}
} else {
av_log(ctx, AV_LOG_WARNING,
"The driver does not permit changing the time per frame\n");
}
}
if (tpf->denominator > 0 && tpf->numerator > 0) {
ctx->streams[0]->avg_frame_rate.num = tpf->denominator;
ctx->streams[0]->avg_frame_rate.den = tpf->numerator;
ctx->streams[0]->r_frame_rate = ctx->streams[0]->avg_frame_rate;
} else
av_log(ctx, AV_LOG_WARNING, "Time per frame unknown\n");
return 0;
}
static int device_try_init(AVFormatContext *ctx,
enum AVPixelFormat pix_fmt,
int *width,
int *height,
uint32_t *desired_format,
enum AVCodecID *codec_id)
{
int ret, i;
*desired_format = ff_fmt_ff2v4l(pix_fmt, ctx->video_codec_id);
if (*desired_format) {
ret = device_init(ctx, width, height, *desired_format);
if (ret < 0) {
*desired_format = 0;
if (ret != AVERROR(EINVAL))
return ret;
}
}
if (!*desired_format) {
for (i = 0; ff_fmt_conversion_table[i].codec_id != AV_CODEC_ID_NONE; i++) {
if (ctx->video_codec_id == AV_CODEC_ID_NONE ||
ff_fmt_conversion_table[i].codec_id == ctx->video_codec_id) {
av_log(ctx, AV_LOG_DEBUG, "Trying to set codec:%s pix_fmt:%s\n",
avcodec_get_name(ff_fmt_conversion_table[i].codec_id),
(char *)av_x_if_null(av_get_pix_fmt_name(ff_fmt_conversion_table[i].ff_fmt), "none"));
*desired_format = ff_fmt_conversion_table[i].v4l2_fmt;
ret = device_init(ctx, width, height, *desired_format);
if (ret >= 0)
break;
else if (ret != AVERROR(EINVAL))
return ret;
*desired_format = 0;
}
}
if (*desired_format == 0) {
av_log(ctx, AV_LOG_ERROR, "Cannot find a proper format for "
"codec '%s' (id %d), pixel format '%s' (id %d)\n",
avcodec_get_name(ctx->video_codec_id), ctx->video_codec_id,
(char *)av_x_if_null(av_get_pix_fmt_name(pix_fmt), "none"), pix_fmt);
ret = AVERROR(EINVAL);
}
}
*codec_id = ff_fmt_v4l2codec(*desired_format);
if (*codec_id == AV_CODEC_ID_NONE)
av_assert0(ret == AVERROR(EINVAL));
return ret;
}
static int v4l2_read_probe(const AVProbeData *p)
{
if (av_strstart(p->filename, "/dev/video", NULL))
return AVPROBE_SCORE_MAX - 1;
return 0;
}
static int v4l2_read_header(AVFormatContext *ctx)
{
struct video_data *s = ctx->priv_data;
AVStream *st;
int res = 0;
uint32_t desired_format;
enum AVCodecID codec_id = AV_CODEC_ID_NONE;
enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;
struct v4l2_input input = { 0 };
st = avformat_new_stream(ctx, NULL);
if (!st)
return AVERROR(ENOMEM);
#if CONFIG_LIBV4L2
/* silence libv4l2 logging. if fopen() fails v4l2_log_file will be NULL
and errors will get sent to stderr */
if (s->use_libv4l2)
v4l2_log_file = fopen("/dev/null", "w");
#endif
s->fd = device_open(ctx, ctx->url);
if (s->fd < 0)
return s->fd;
if (s->channel != -1) {
/* set video input */
av_log(ctx, AV_LOG_DEBUG, "Selecting input_channel: %d\n", s->channel);
if (v4l2_ioctl(s->fd, VIDIOC_S_INPUT, &s->channel) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_INPUT): %s\n", av_err2str(res));
goto fail;
}
} else {
/* get current video input */
if (v4l2_ioctl(s->fd, VIDIOC_G_INPUT, &s->channel) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_G_INPUT): %s\n", av_err2str(res));
goto fail;
}
}
/* enum input */
input.index = s->channel;
if (v4l2_ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMINPUT): %s\n", av_err2str(res));
goto fail;
}
s->std_id = input.std;
av_log(ctx, AV_LOG_DEBUG, "Current input_channel: %d, input_name: %s, input_std: %"PRIx64"\n",
s->channel, input.name, (uint64_t)input.std);
if (s->list_format) {
list_formats(ctx, s->list_format);
res = AVERROR_EXIT;
goto fail;
}
if (s->list_standard) {
list_standards(ctx);
res = AVERROR_EXIT;
goto fail;
}
avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
if (s->pixel_format) {
const AVCodecDescriptor *desc = avcodec_descriptor_get_by_name(s->pixel_format);
if (desc)
ctx->video_codec_id = desc->id;
pix_fmt = av_get_pix_fmt(s->pixel_format);
if (pix_fmt == AV_PIX_FMT_NONE && !desc) {
av_log(ctx, AV_LOG_ERROR, "No such input format: %s.\n",
s->pixel_format);
res = AVERROR(EINVAL);
goto fail;
}
}
if (!s->width && !s->height) {
struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
av_log(ctx, AV_LOG_VERBOSE,
"Querying the device for the current frame size\n");
if (v4l2_ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
res = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n",
av_err2str(res));
goto fail;
}
s->width = fmt.fmt.pix.width;
s->height = fmt.fmt.pix.height;
av_log(ctx, AV_LOG_VERBOSE,
"Setting frame size to %dx%d\n", s->width, s->height);
}
res = device_try_init(ctx, pix_fmt, &s->width, &s->height, &desired_format, &codec_id);
if (res < 0)
goto fail;
/* If no pixel_format was specified, the codec_id was not known up
* until now. Set video_codec_id in the context, as codec_id will
* not be available outside this function
*/
if (codec_id != AV_CODEC_ID_NONE && ctx->video_codec_id == AV_CODEC_ID_NONE)
ctx->video_codec_id = codec_id;
if ((res = av_image_check_size(s->width, s->height, 0, ctx)) < 0)
goto fail;
s->pixelformat = desired_format;
if ((res = v4l2_set_parameters(ctx)) < 0)
goto fail;
st->codecpar->format = ff_fmt_v4l2ff(desired_format, codec_id);
if (st->codecpar->format != AV_PIX_FMT_NONE)
s->frame_size = av_image_get_buffer_size(st->codecpar->format,
s->width, s->height, 1);
if ((res = mmap_init(ctx)) ||
(res = mmap_start(ctx)) < 0)
goto fail;
s->top_field_first = first_field(s);
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = codec_id;
if (codec_id == AV_CODEC_ID_RAWVIDEO)
st->codecpar->codec_tag =
avcodec_pix_fmt_to_codec_tag(st->codecpar->format);
else if (codec_id == AV_CODEC_ID_H264) {
avpriv_stream_set_need_parsing(st, AVSTREAM_PARSE_FULL_ONCE);
}
if (desired_format == V4L2_PIX_FMT_YVU420)
st->codecpar->codec_tag = MKTAG('Y', 'V', '1', '2');
else if (desired_format == V4L2_PIX_FMT_YVU410)
st->codecpar->codec_tag = MKTAG('Y', 'V', 'U', '9');
st->codecpar->width = s->width;
st->codecpar->height = s->height;
if (st->avg_frame_rate.den)
st->codecpar->bit_rate = s->frame_size * av_q2d(st->avg_frame_rate) * 8;
return 0;
fail:
v4l2_close(s->fd);
return res;
}
static int v4l2_read_packet(AVFormatContext *ctx, AVPacket *pkt)
{
int res;
if ((res = mmap_read_frame(ctx, pkt)) < 0) {
return res;
}
return pkt->size;
}
static int v4l2_read_close(AVFormatContext *ctx)
{
struct video_data *s = ctx->priv_data;
if (atomic_load(&s->buffers_queued) != s->buffers)
av_log(ctx, AV_LOG_WARNING, "Some buffers are still owned by the caller on "
"close.\n");
mmap_close(s);
v4l2_close(s->fd);
return 0;
}
static int v4l2_is_v4l_dev(const char *name)
{
return !strncmp(name, "video", 5) ||
!strncmp(name, "radio", 5) ||
!strncmp(name, "vbi", 3) ||
!strncmp(name, "v4l-subdev", 10);
}
static int v4l2_get_device_list(AVFormatContext *ctx, AVDeviceInfoList *device_list)
{
struct video_data *s = ctx->priv_data;
DIR *dir;
struct dirent *entry;
int ret = 0;
if (!device_list)
return AVERROR(EINVAL);
dir = opendir("/dev");
if (!dir) {
ret = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "Couldn't open the directory: %s\n", av_err2str(ret));
return ret;
}
while ((entry = readdir(dir))) {
AVDeviceInfo *device = NULL;
struct v4l2_capability cap;
int fd = -1, size;
char device_name[256];
if (!v4l2_is_v4l_dev(entry->d_name))
continue;
size = snprintf(device_name, sizeof(device_name), "/dev/%s", entry->d_name);
if (size >= sizeof(device_name)) {
av_log(ctx, AV_LOG_ERROR, "Device name too long.\n");
ret = AVERROR(ENOSYS);
break;
}
if ((fd = device_open(ctx, device_name)) < 0)
continue;
if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
ret = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n", av_err2str(ret));
goto fail;
}
device = av_mallocz(sizeof(AVDeviceInfo));
if (!device) {
ret = AVERROR(ENOMEM);
goto fail;
}
device->device_name = av_strdup(device_name);
device->device_description = av_strdup(cap.card);
if (!device->device_name || !device->device_description) {
ret = AVERROR(ENOMEM);
goto fail;
}
if ((ret = av_dynarray_add_nofree(&device_list->devices,
&device_list->nb_devices, device)) < 0)
goto fail;
v4l2_close(fd);
continue;
fail:
if (device) {
av_freep(&device->device_name);
av_freep(&device->device_description);
av_freep(&device);
}
v4l2_close(fd);
break;
}
closedir(dir);
return ret;
}
#define OFFSET(x) offsetof(struct video_data, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "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 },
};
static const AVClass v4l2_class = {
.class_name = "V4L2 indev",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
.category = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
};
const AVInputFormat ff_v4l2_demuxer = {
.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,
};
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