[FFmpeg-devel] [PATCH] v4l2: add libv4l2 support.

Stefano Sabatini stefasab at gmail.com
Sat Nov 5 14:18:19 CET 2011


On date Friday 2011-11-04 20:11:40 +0100, Clément Bœsch encoded:
> On Sun, Oct 30, 2011 at 03:57:41AM +0100, Clément Bœsch wrote:
> > ---
> > Here is a patch to support old webcams with exotic colorspaces or insane
> > drivers using userland libv4l2 (see for instance
> > http://hansdegoede.livejournal.com/3636.html).
> > 
> > It seems to work with my personnal crazy webcam, but more tests are welcome.
> > 
> > I wanted to make the support optional at runtime, but it raises at least one
> > issue: the context has to be transmitted to all subfunctions, which is not
> > easily possible in some cases such as mmap_release_buffer() callback. So ATM,
> > if you build FFmpeg with --enable-libv4l2, then deal with it, you have to use
> > it...
> [...]
> 
> New version attached. I didn't change the strerror() to be consistent with
> the rest of the code (it can be changed later), but the rest should be
> fixed.

Fine.
 
> Still, the runtime support is not present for the issue I raised in the
> previous mail. But if there is no objection I'd like to push this version
> in a few days.

Just please mention in the docs that libv4l2 is used in case it is
enabled in configure.

> 
> -- 
> Clément B.

> From 185715adab6fdbb2c39b455c89f199044a3d981f Mon Sep 17 00:00:00 2001
> From: =?UTF-8?q?Cl=C3=A9ment=20B=C5=93sch?= <ubitux at gmail.com>
> Date: Sun, 30 Oct 2011 03:21:55 +0100
> Subject: [PATCH] v4l2: add libv4l2 support.
> 
> ---
>  configure          |    5 +++
>  libavdevice/v4l2.c |   79 ++++++++++++++++++++++++++++++++++------------------
>  2 files changed, 57 insertions(+), 27 deletions(-)
> 
> diff --git a/configure b/configure
> index 279e416..a617b10 100755
> --- a/configure
> +++ b/configure
> @@ -187,6 +187,7 @@ External library support:
>    --enable-libstagefright-h264  enable H.264 decoding via libstagefright [no]
>    --enable-libtheora       enable Theora encoding via libtheora [no]
>    --enable-libutvideo      enable Ut Video decoding via libutvideo [no]
> +  --enable-libv4l2         enable libv4l2/v4l-utils [no]
>    --enable-libvo-aacenc    enable AAC encoding via libvo-aacenc [no]
>    --enable-libvo-amrwbenc  enable AMR-WB encoding via libvo-amrwbenc [no]
>    --enable-libvorbis       enable Vorbis encoding via libvorbis,
> @@ -1022,6 +1023,7 @@ CONFIG_LIST="
>      libstagefright_h264
>      libtheora
>      libutvideo
> +    libv4l2
>      libvo_aacenc
>      libvo_amrwbenc
>      libvorbis
> @@ -1568,6 +1570,7 @@ jack_indev_deps="jack_jack_h sem_timedwait"
>  lavfi_indev_deps="avfilter"
>  libcdio_indev_deps="libcdio"
>  libdc1394_indev_deps="libdc1394"
> +libv4l2_indev_deps="libv4l2"
>  openal_indev_deps="openal"
>  oss_indev_deps_any="soundcard_h sys_soundcard_h"
>  oss_outdev_deps_any="soundcard_h sys_soundcard_h"
> @@ -3053,6 +3056,7 @@ enabled libstagefright_h264  && require_cpp libstagefright_h264 "binder/ProcessS
>      media/stagefright/OMXClient.h media/stagefright/OMXCodec.h" android::OMXClient -lstagefright -lmedia -lutils -lbinder
>  enabled libtheora  && require  libtheora theora/theoraenc.h th_info_init -ltheoraenc -ltheoradec -logg
>  enabled libutvideo    && require_cpp utvideo "stdint.h stdlib.h utvideo/utvideo.h utvideo/Codec.h" 'CCodec*' -lutvideo -lstdc++
> +enabled libv4l2    && require_pkg_config libv4l2 libv4l2.h v4l2_ioctl
>  enabled libvo_aacenc && require libvo_aacenc vo-aacenc/voAAC.h voGetAACEncAPI -lvo-aacenc
>  enabled libvo_amrwbenc && require libvo_amrwbenc vo-amrwbenc/enc_if.h E_IF_init -lvo-amrwbenc
>  enabled libvorbis  && require  libvorbis vorbis/vorbisenc.h vorbis_info_init -lvorbisenc -lvorbis -logg
> @@ -3381,6 +3385,7 @@ echo "libspeex enabled          ${libspeex-no}"
>  echo "libstagefright-h264 enabled    ${libstagefright_h264-no}"
>  echo "libtheora enabled         ${libtheora-no}"
>  echo "libutvideo enabled        ${libutvideo-no}"
> +echo "libv4l2 enabled           ${libv4l2-no}"
>  echo "libvo-aacenc support      ${libvo_aacenc-no}"
>  echo "libvo-amrwbenc support    ${libvo_amrwbenc-no}"
>  echo "libvorbis enabled         ${libvorbis-no}"
> diff --git a/libavdevice/v4l2.c b/libavdevice/v4l2.c
> index e327cb0..85666f5 100644
> --- a/libavdevice/v4l2.c
> +++ b/libavdevice/v4l2.c
> @@ -52,6 +52,18 @@
>  #include "libavutil/pixdesc.h"
>  #include "libavutil/avstring.h"
>  
> +#if CONFIG_LIBV4L2
> +#include <libv4l2.h>
> +#else
> +#define v4l2_open   open
> +#define v4l2_close  close
> +#define v4l2_dup    dup
> +#define v4l2_ioctl  ioctl
> +#define v4l2_read   read
> +#define v4l2_mmap   mmap
> +#define v4l2_munmap munmap
> +#endif
> +
>  static const int desired_video_buffers = 256;
>  
>  enum io_method {
> @@ -113,36 +125,49 @@ static int device_open(AVFormatContext *ctx, uint32_t *capabilities)
>  {
>      struct v4l2_capability cap;
>      int fd;
> +#if CONFIG_LIBV4L2
> +    int fd_libv4l;
> +#endif
>      int res, err;
>      int flags = O_RDWR;
>  
>      if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
>          flags |= O_NONBLOCK;
>      }
> -    fd = open(ctx->filename, flags, 0);
> +    fd = v4l2_open(ctx->filename, flags, 0);
>      if (fd < 0) {
>          av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s : %s\n",
>                   ctx->filename, strerror(errno));
>          return AVERROR(errno);
>      }
> +#if CONFIG_LIBV4L2
> +    fd_libv4l = v4l2_fd_open(fd, 0);
> +    if (fd < 0) {
> +        err = AVERROR(errno);
> +        av_log(ctx, AV_LOG_ERROR, "Cannot open video device with libv4l neither %s : %s\n",
> +               ctx->filename, strerror(errno));
> +        return err;
> +    }
> +    fd = fd_libv4l;
> +#endif
>  
> -    res = ioctl(fd, VIDIOC_QUERYCAP, &cap);
> +    res = v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap);
>      // ENOIOCTLCMD definition only availble on __KERNEL__
>      if (res < 0 && ((err = errno) == 515)) {
>          av_log(ctx, AV_LOG_ERROR, "QUERYCAP not implemented, probably V4L device but not supporting V4L2\n");
> -        close(fd);
> +        v4l2_close(fd);
>  
>          return AVERROR(515);
>      }
>      if (res < 0) {
>          av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
>                   strerror(errno));
> -        close(fd);
> +        v4l2_close(fd);
>          return AVERROR(err);
>      }
>      if ((cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) == 0) {
>          av_log(ctx, AV_LOG_ERROR, "Not a video capture device\n");
> -        close(fd);
> +        v4l2_close(fd);
>          return AVERROR(ENODEV);
>      }
>      *capabilities = cap.capabilities;
> @@ -162,7 +187,7 @@ static int device_init(AVFormatContext *ctx, int *width, int *height, uint32_t p
>      fmt.fmt.pix.height = *height;
>      fmt.fmt.pix.pixelformat = pix_fmt;
>      fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
> -    res = ioctl(fd, VIDIOC_S_FMT, &fmt);
> +    res = v4l2_ioctl(fd, VIDIOC_S_FMT, &fmt);
>      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;
> @@ -182,7 +207,7 @@ static int first_field(int fd)
>      int res;
>      v4l2_std_id std;
>  
> -    res = ioctl(fd, VIDIOC_G_STD, &std);
> +    res = v4l2_ioctl(fd, VIDIOC_G_STD, &std);
>      if (res < 0) {
>          return 0;
>      }
> @@ -245,7 +270,7 @@ static int mmap_init(AVFormatContext *ctx)
>      req.count = desired_video_buffers;
>      req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
>      req.memory = V4L2_MEMORY_MMAP;
> -    res = ioctl(s->fd, VIDIOC_REQBUFS, &req);
> +    res = v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req);
>      if (res < 0) {
>          if (errno == EINVAL) {
>              av_log(ctx, AV_LOG_ERROR, "Device does not support mmap\n");
> @@ -278,7 +303,7 @@ static int mmap_init(AVFormatContext *ctx)
>          buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
>          buf.memory = V4L2_MEMORY_MMAP;
>          buf.index = i;
> -        res = ioctl(s->fd, VIDIOC_QUERYBUF, &buf);
> +        res = v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf);
>          if (res < 0) {
>              av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF)\n");
>              return AVERROR(errno);
> @@ -290,7 +315,7 @@ static int mmap_init(AVFormatContext *ctx)
>  
>              return -1;
>          }
> -        s->buf_start[i] = mmap (NULL, buf.length,
> +        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) {
>              av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));
> @@ -322,7 +347,7 @@ static void mmap_release_buffer(AVPacket *pkt)
>      fd = buf_descriptor->fd;
>      av_free(buf_descriptor);
>  
> -    res = ioctl(fd, VIDIOC_QBUF, &buf);
> +    res = v4l2_ioctl(fd, VIDIOC_QBUF, &buf);
>      if (res < 0) {
>          av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno));
>      }
> @@ -341,7 +366,7 @@ static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
>      buf.memory = V4L2_MEMORY_MMAP;
>  
>      /* FIXME: Some special treatment might be needed in case of loss of signal... */
> -    while ((res = ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
> +    while ((res = v4l2_ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
>      if (res < 0) {
>          if (errno == EAGAIN) {
>              pkt->size = 0;
> @@ -368,7 +393,7 @@ static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
>           * allocate a buffer for memcopying into it
>           */
>          av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");
> -        res = ioctl(s->fd, VIDIOC_QBUF, &buf);
> +        res = v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf);
>  
>          return AVERROR(ENOMEM);
>      }
> @@ -397,7 +422,7 @@ static int mmap_start(AVFormatContext *ctx)
>          buf.memory = V4L2_MEMORY_MMAP;
>          buf.index  = i;
>  
> -        res = ioctl(s->fd, VIDIOC_QBUF, &buf);
> +        res = v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf);
>          if (res < 0) {
>              av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno));
>              return AVERROR(errno);
> @@ -405,7 +430,7 @@ static int mmap_start(AVFormatContext *ctx)
>      }
>  
>      type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> -    res = ioctl(s->fd, VIDIOC_STREAMON, &type);
> +    res = v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type);
>      if (res < 0) {
>          av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n", strerror(errno));
>          return AVERROR(errno);
> @@ -423,9 +448,9 @@ static void mmap_close(struct video_data *s)
>      /* We do not check for the result, because we could
>       * not do anything about it anyway...
>       */
> -    ioctl(s->fd, VIDIOC_STREAMOFF, &type);
> +    v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);
>      for (i = 0; i < s->buffers; i++) {
> -        munmap(s->buf_start[i], s->buf_len[i]);
> +        v4l2_munmap(s->buf_start[i], s->buf_len[i]);
>      }
>      av_free(s->buf_start);
>      av_free(s->buf_len);
> @@ -450,14 +475,14 @@ static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
>  
>      /* set tv video input */
>      input.index = s->channel;
> -    if (ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
> +    if (v4l2_ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
>          av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl enum input failed:\n");
>          return AVERROR(EIO);
>      }
>  
>      av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set input_id: %d, input: %s\n",
>              s->channel, input.name);
> -    if (ioctl(s->fd, VIDIOC_S_INPUT, &input.index) < 0) {
> +    if (v4l2_ioctl(s->fd, VIDIOC_S_INPUT, &input.index) < 0) {
>          av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set input(%d) failed\n",
>                  s->channel);
>          return AVERROR(EIO);
> @@ -469,7 +494,7 @@ static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
>          /* set tv standard */
>          for (i = 0;; i++) {
>              standard.index = i;
> -            ret = ioctl(s->fd, VIDIOC_ENUMSTD, &standard);
> +            ret = v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard);
>              if (ret < 0 || !av_strcasecmp(standard.name, s->standard))
>                  break;
>          }
> @@ -480,7 +505,7 @@ static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
>  
>          av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s, id: %"PRIu64"\n",
>                 s->standard, (uint64_t)standard.id);
> -        if (ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
> +        if (v4l2_ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
>              av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n",
>                     s->standard);
>              return AVERROR(EIO);
> @@ -492,7 +517,7 @@ static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
>                 framerate_q.den, framerate_q.num);
>          tpf->numerator   = framerate_q.den;
>          tpf->denominator = framerate_q.num;
> -        if (ioctl(s->fd, VIDIOC_S_PARM, &streamparm) != 0) {
> +        if (v4l2_ioctl(s->fd, VIDIOC_S_PARM, &streamparm) != 0) {
>              av_log(s1, AV_LOG_ERROR,
>                     "ioctl set time per frame(%d/%d) failed\n",
>                     framerate_q.den, framerate_q.num);
> @@ -508,7 +533,7 @@ static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
>          }
>      } else {
>          /* if timebase value is not set, read the timebase value from the driver */
> -        if (ioctl(s->fd, VIDIOC_G_PARM, &streamparm) != 0) {
> +        if (v4l2_ioctl(s->fd, VIDIOC_G_PARM, &streamparm) != 0) {
>              av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_PARM): %s\n", strerror(errno));
>              return AVERROR(errno);
>          }
> @@ -590,7 +615,7 @@ static int v4l2_read_header(AVFormatContext *s1, AVFormatParameters *ap)
>  
>          av_log(s1, AV_LOG_VERBOSE, "Querying the device for the current frame size\n");
>          fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> -        if (ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
> +        if (v4l2_ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
>              av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", strerror(errno));
>              res = AVERROR(errno);
>              goto out;
> @@ -604,7 +629,7 @@ static int v4l2_read_header(AVFormatContext *s1, AVFormatParameters *ap)
>      if (desired_format == 0) {
>          av_log(s1, AV_LOG_ERROR, "Cannot find a proper format for "
>                 "codec_id %d, pix_fmt %d.\n", s1->video_codec_id, pix_fmt);
> -        close(s->fd);
> +        v4l2_close(s->fd);
>  
>          res = AVERROR(EIO);
>          goto out;
> @@ -629,7 +654,7 @@ static int v4l2_read_header(AVFormatContext *s1, AVFormatParameters *ap)
>          res = read_init(s1);
>      }
>      if (res < 0) {
> -        close(s->fd);
> +        v4l2_close(s->fd);
>          res = AVERROR(EIO);
>          goto out;
>      }
> @@ -681,7 +706,7 @@ static int v4l2_read_close(AVFormatContext *s1)
>          mmap_close(s);
>      }
>  
> -    close(s->fd);
> +    v4l2_close(s->fd);
>      return 0;
>  }

Looks fine otherwise.
-- 
FFmpeg = Fundamentalist and Fucking Marvellous Peaceful Egregious Game


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