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ffmpeg/libavdevice/v4l2.c
Jaroslav Beran 00a1e1337f libavdevice/v4l2: fix invalid access to struct v4l2_buffer 
In case we are short of queued buffers, at first v4l2_buffer was enqueued to kernel so it's not owned by
user-space anymore. After that it's timestamp field was read, but it might be overwritten by driver at
that moment. It resulted in invalid timestamp sometimes.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2017-09-24 02:33:48 +02:00

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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 "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);
int (*ioctl_f)(int fd, unsigned long int request, ...);
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)
{
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(ctx->filename, flags, 0);
if (fd < 0) {
err = AVERROR(errno);
av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s: %s\n",
ctx->filename, 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_ERROR,
"Dequeued v4l2 buffer contains %d bytes, but %d were expected. Flags: 0x%08X.\n",
buf.bytesused, s->frame_size, buf.flags);
enqueue_buffer(s, &buf);
return AVERROR_INVALIDDATA;
}
}
/* 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);
av_assert0(*codec_id != AV_CODEC_ID_NONE);
return ret;
}
static int v4l2_read_probe(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);
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) {
st->need_parsing = 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)
{
#if FF_API_CODED_FRAME && FF_API_LAVF_AVCTX
FF_DISABLE_DEPRECATION_WARNINGS
struct video_data *s = ctx->priv_data;
AVFrame *frame = ctx->streams[0]->codec->coded_frame;
FF_ENABLE_DEPRECATION_WARNINGS
#endif
int res;
if ((res = mmap_read_frame(ctx, pkt)) < 0) {
return res;
}
#if FF_API_CODED_FRAME && FF_API_LAVF_AVCTX
FF_DISABLE_DEPRECATION_WARNINGS
if (frame && s->interlaced) {
frame->interlaced_frame = 1;
frame->top_field_first = s->top_field_first;
}
FF_ENABLE_DEPRECATION_WARNINGS
#endif
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;
AVDeviceInfo *device = NULL;
struct v4l2_capability cap;
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))) {
if (!v4l2_is_v4l_dev(entry->d_name))
continue;
snprintf(ctx->filename, sizeof(ctx->filename), "/dev/%s", entry->d_name);
if ((s->fd = device_open(ctx)) < 0)
continue;
if (v4l2_ioctl(s->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(ctx->filename);
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(s->fd);
s->fd = -1;
continue;
fail:
if (device) {
av_freep(&device->device_name);
av_freep(&device->device_description);
av_freep(&device);
}
if (s->fd >= 0)
v4l2_close(s->fd);
s->fd = -1;
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,
};
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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