FFmpeg: libavdevice/v4l2.c Source File

00001 /*
00002  * Copyright (c) 2000,2001 Fabrice Bellard
00003  * Copyright (c) 2006 Luca Abeni
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00033 #undef __STRICT_ANSI__ //workaround due to broken kernel headers
00034 #include "config.h"
00035 #include "libavformat/internal.h"
00036 #include <unistd.h>
00037 #include <fcntl.h>
00038 #include <sys/ioctl.h>
00039 #include <sys/mman.h>
00040 #include <sys/time.h>
00041 #if HAVE_SYS_VIDEOIO_H
00042 #include <sys/videoio.h>
00043 #else
00044 #if HAVE_ASM_TYPES_H
00045 #include <asm/types.h>
00046 #endif
00047 #include <linux/videodev2.h>
00048 #endif
00049 #include "libavutil/avassert.h"
00050 #include "libavutil/imgutils.h"
00051 #include "libavutil/log.h"
00052 #include "libavutil/opt.h"
00053 #include "avdevice.h"
00054 #include "timefilter.h"
00055 #include "libavutil/parseutils.h"
00056 #include "libavutil/pixdesc.h"
00057 #include "libavutil/avstring.h"
00058 
00059 #if CONFIG_LIBV4L2
00060 #include <libv4l2.h>
00061 #else
00062 #define v4l2_open   open
00063 #define v4l2_close  close
00064 #define v4l2_dup    dup
00065 #define v4l2_ioctl  ioctl
00066 #define v4l2_read   read
00067 #define v4l2_mmap   mmap
00068 #define v4l2_munmap munmap
00069 #endif
00070 
00071 static const int desired_video_buffers = 256;
00072 
00073 #define V4L_ALLFORMATS  3
00074 #define V4L_RAWFORMATS  1
00075 #define V4L_COMPFORMATS 2
00076 
00080 #define V4L_TS_DEFAULT  0
00081 
00085 #define V4L_TS_ABS      1
00086 
00090 #define V4L_TS_MONO2ABS 2
00091 
00097 #define V4L_TS_CONVERT_READY V4L_TS_DEFAULT
00098 
00099 struct video_data {
00100     AVClass *class;
00101     int fd;
00102     int frame_format; /* V4L2_PIX_FMT_* */
00103     int width, height;
00104     int frame_size;
00105     int interlaced;
00106     int top_field_first;
00107     int ts_mode;
00108     TimeFilter *timefilter;
00109     int64_t last_time_m;
00110 
00111     int buffers;
00112     void **buf_start;
00113     unsigned int *buf_len;
00114     char *standard;
00115     int channel;
00116     char *pixel_format; 
00117     int list_format;    
00118     char *framerate;    
00119 };
00120 
00121 struct buff_data {
00122     int index;
00123     int fd;
00124 };
00125 
00126 struct fmt_map {
00127     enum PixelFormat ff_fmt;
00128     enum AVCodecID codec_id;
00129     uint32_t v4l2_fmt;
00130 };
00131 
00132 static struct fmt_map fmt_conversion_table[] = {
00133     //ff_fmt           codec_id           v4l2_fmt
00134     { PIX_FMT_YUV420P, AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV420  },
00135     { PIX_FMT_YUV420P, AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YVU420  },
00136     { PIX_FMT_YUV422P, AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV422P },
00137     { PIX_FMT_YUYV422, AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUYV    },
00138     { PIX_FMT_UYVY422, AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_UYVY    },
00139     { PIX_FMT_YUV411P, AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV411P },
00140     { PIX_FMT_YUV410P, AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV410  },
00141     { PIX_FMT_RGB555LE,AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB555  },
00142     { PIX_FMT_RGB555BE,AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB555X },
00143     { PIX_FMT_RGB565LE,AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB565  },
00144     { PIX_FMT_RGB565BE,AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB565X },
00145     { PIX_FMT_BGR24,   AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR24   },
00146     { PIX_FMT_RGB24,   AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB24   },
00147     { PIX_FMT_BGR0,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR32   },
00148     { PIX_FMT_0RGB,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB32   },
00149     { PIX_FMT_GRAY8,   AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_GREY    },
00150     { PIX_FMT_NV12,    AV_CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_NV12    },
00151     { PIX_FMT_NONE,    AV_CODEC_ID_MJPEG,    V4L2_PIX_FMT_MJPEG   },
00152     { PIX_FMT_NONE,    AV_CODEC_ID_MJPEG,    V4L2_PIX_FMT_JPEG    },
00153 #ifdef V4L2_PIX_FMT_CPIA1
00154     { PIX_FMT_NONE,    AV_CODEC_ID_CPIA,     V4L2_PIX_FMT_CPIA1   },
00155 #endif
00156 };
00157 
00158 static int device_open(AVFormatContext *ctx)
00159 {
00160     struct v4l2_capability cap;
00161     int fd;
00162     int res, err;
00163     int flags = O_RDWR;
00164 
00165     if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
00166         flags |= O_NONBLOCK;
00167     }
00168 
00169     fd = v4l2_open(ctx->filename, flags, 0);
00170     if (fd < 0) {
00171         err = errno;
00172 
00173         av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s : %s\n",
00174                ctx->filename, strerror(err));
00175 
00176         return AVERROR(err);
00177     }
00178 
00179     res = v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap);
00180     if (res < 0) {
00181         err = errno;
00182         av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
00183                strerror(err));
00184 
00185         goto fail;
00186     }
00187 
00188     av_log(ctx, AV_LOG_VERBOSE, "[%d]Capabilities: %x\n",
00189            fd, cap.capabilities);
00190 
00191     if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
00192         av_log(ctx, AV_LOG_ERROR, "Not a video capture device.\n");
00193         err = ENODEV;
00194 
00195         goto fail;
00196     }
00197 
00198     if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
00199         av_log(ctx, AV_LOG_ERROR,
00200                "The device does not support the streaming I/O method.\n");
00201         err = ENOSYS;
00202 
00203         goto fail;
00204     }
00205 
00206     return fd;
00207 
00208 fail:
00209     v4l2_close(fd);
00210     return AVERROR(err);
00211 }
00212 
00213 static int device_init(AVFormatContext *ctx, int *width, int *height,
00214                        uint32_t pix_fmt)
00215 {
00216     struct video_data *s = ctx->priv_data;
00217     int fd = s->fd;
00218     struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
00219     struct v4l2_pix_format *pix = &fmt.fmt.pix;
00220 
00221     int res;
00222 
00223     pix->width = *width;
00224     pix->height = *height;
00225     pix->pixelformat = pix_fmt;
00226     pix->field = V4L2_FIELD_ANY;
00227 
00228     res = v4l2_ioctl(fd, VIDIOC_S_FMT, &fmt);
00229 
00230     if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) {
00231         av_log(ctx, AV_LOG_INFO,
00232                "The V4L2 driver changed the video from %dx%d to %dx%d\n",
00233                *width, *height, fmt.fmt.pix.width, fmt.fmt.pix.height);
00234         *width = fmt.fmt.pix.width;
00235         *height = fmt.fmt.pix.height;
00236     }
00237 
00238     if (pix_fmt != fmt.fmt.pix.pixelformat) {
00239         av_log(ctx, AV_LOG_DEBUG,
00240                "The V4L2 driver changed the pixel format "
00241                "from 0x%08X to 0x%08X\n",
00242                pix_fmt, fmt.fmt.pix.pixelformat);
00243         res = -1;
00244     }
00245 
00246     if (fmt.fmt.pix.field == V4L2_FIELD_INTERLACED) {
00247         av_log(ctx, AV_LOG_DEBUG, "The V4L2 driver using the interlaced mode");
00248         s->interlaced = 1;
00249     }
00250 
00251     return res;
00252 }
00253 
00254 static int first_field(int fd)
00255 {
00256     int res;
00257     v4l2_std_id std;
00258 
00259     res = v4l2_ioctl(fd, VIDIOC_G_STD, &std);
00260     if (res < 0) {
00261         return 0;
00262     }
00263     if (std & V4L2_STD_NTSC) {
00264         return 0;
00265     }
00266 
00267     return 1;
00268 }
00269 
00270 static uint32_t fmt_ff2v4l(enum PixelFormat pix_fmt, enum AVCodecID codec_id)
00271 {
00272     int i;
00273 
00274     for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
00275         if ((codec_id == AV_CODEC_ID_NONE ||
00276              fmt_conversion_table[i].codec_id == codec_id) &&
00277             (pix_fmt == PIX_FMT_NONE ||
00278              fmt_conversion_table[i].ff_fmt == pix_fmt)) {
00279             return fmt_conversion_table[i].v4l2_fmt;
00280         }
00281     }
00282 
00283     return 0;
00284 }
00285 
00286 static enum PixelFormat fmt_v4l2ff(uint32_t v4l2_fmt, enum AVCodecID codec_id)
00287 {
00288     int i;
00289 
00290     for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
00291         if (fmt_conversion_table[i].v4l2_fmt == v4l2_fmt &&
00292             fmt_conversion_table[i].codec_id == codec_id) {
00293             return fmt_conversion_table[i].ff_fmt;
00294         }
00295     }
00296 
00297     return PIX_FMT_NONE;
00298 }
00299 
00300 static enum AVCodecID fmt_v4l2codec(uint32_t v4l2_fmt)
00301 {
00302     int i;
00303 
00304     for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
00305         if (fmt_conversion_table[i].v4l2_fmt == v4l2_fmt) {
00306             return fmt_conversion_table[i].codec_id;
00307         }
00308     }
00309 
00310     return AV_CODEC_ID_NONE;
00311 }
00312 
00313 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
00314 static void list_framesizes(AVFormatContext *ctx, int fd, uint32_t pixelformat)
00315 {
00316     struct v4l2_frmsizeenum vfse = { .pixel_format = pixelformat };
00317 
00318     while(!ioctl(fd, VIDIOC_ENUM_FRAMESIZES, &vfse)) {
00319         switch (vfse.type) {
00320         case V4L2_FRMSIZE_TYPE_DISCRETE:
00321             av_log(ctx, AV_LOG_INFO, " %ux%u",
00322                    vfse.discrete.width, vfse.discrete.height);
00323         break;
00324         case V4L2_FRMSIZE_TYPE_CONTINUOUS:
00325         case V4L2_FRMSIZE_TYPE_STEPWISE:
00326             av_log(ctx, AV_LOG_INFO, " {%u-%u, %u}x{%u-%u, %u}",
00327                    vfse.stepwise.min_width,
00328                    vfse.stepwise.max_width,
00329                    vfse.stepwise.step_width,
00330                    vfse.stepwise.min_height,
00331                    vfse.stepwise.max_height,
00332                    vfse.stepwise.step_height);
00333         }
00334         vfse.index++;
00335     }
00336 }
00337 #endif
00338 
00339 static void list_formats(AVFormatContext *ctx, int fd, int type)
00340 {
00341     struct v4l2_fmtdesc vfd = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
00342 
00343     while(!ioctl(fd, VIDIOC_ENUM_FMT, &vfd)) {
00344         enum AVCodecID codec_id = fmt_v4l2codec(vfd.pixelformat);
00345         enum PixelFormat pix_fmt = fmt_v4l2ff(vfd.pixelformat, codec_id);
00346 
00347         vfd.index++;
00348 
00349         if (!(vfd.flags & V4L2_FMT_FLAG_COMPRESSED) &&
00350             type & V4L_RAWFORMATS) {
00351             const char *fmt_name = av_get_pix_fmt_name(pix_fmt);
00352             av_log(ctx, AV_LOG_INFO, "R : %9s : %20s :",
00353                    fmt_name ? fmt_name : "Unsupported",
00354                    vfd.description);
00355         } else if (vfd.flags & V4L2_FMT_FLAG_COMPRESSED &&
00356                    type & V4L_COMPFORMATS) {
00357             AVCodec *codec = avcodec_find_encoder(codec_id);
00358             av_log(ctx, AV_LOG_INFO, "C : %9s : %20s :",
00359                    codec ? codec->name : "Unsupported",
00360                    vfd.description);
00361         } else {
00362             continue;
00363         }
00364 
00365 #ifdef V4L2_FMT_FLAG_EMULATED
00366         if (vfd.flags & V4L2_FMT_FLAG_EMULATED) {
00367             av_log(ctx, AV_LOG_WARNING, "%s", "Emulated");
00368             continue;
00369         }
00370 #endif
00371 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
00372         list_framesizes(ctx, fd, vfd.pixelformat);
00373 #endif
00374         av_log(ctx, AV_LOG_INFO, "\n");
00375     }
00376 }
00377 
00378 static int mmap_init(AVFormatContext *ctx)
00379 {
00380     int i, res;
00381     struct video_data *s = ctx->priv_data;
00382     struct v4l2_requestbuffers req = {
00383         .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
00384         .count  = desired_video_buffers,
00385         .memory = V4L2_MEMORY_MMAP
00386     };
00387 
00388     res = v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req);
00389     if (res < 0) {
00390         if (errno == EINVAL) {
00391             av_log(ctx, AV_LOG_ERROR, "Device does not support mmap\n");
00392         } else {
00393             av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS)\n");
00394         }
00395         return AVERROR(errno);
00396     }
00397 
00398     if (req.count < 2) {
00399         av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n");
00400         return AVERROR(ENOMEM);
00401     }
00402     s->buffers = req.count;
00403     s->buf_start = av_malloc(sizeof(void *) * s->buffers);
00404     if (s->buf_start == NULL) {
00405         av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer pointers\n");
00406         return AVERROR(ENOMEM);
00407     }
00408     s->buf_len = av_malloc(sizeof(unsigned int) * s->buffers);
00409     if (s->buf_len == NULL) {
00410         av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer sizes\n");
00411         av_free(s->buf_start);
00412         return AVERROR(ENOMEM);
00413     }
00414 
00415     for (i = 0; i < req.count; i++) {
00416         struct v4l2_buffer buf = {
00417             .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
00418             .index  = i,
00419             .memory = V4L2_MEMORY_MMAP
00420         };
00421         res = v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf);
00422         if (res < 0) {
00423             av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF)\n");
00424             return AVERROR(errno);
00425         }
00426 
00427         s->buf_len[i] = buf.length;
00428         if (s->frame_size > 0 && s->buf_len[i] < s->frame_size) {
00429             av_log(ctx, AV_LOG_ERROR,
00430                    "Buffer len [%d] = %d != %d\n",
00431                    i, s->buf_len[i], s->frame_size);
00432 
00433             return -1;
00434         }
00435         s->buf_start[i] = v4l2_mmap(NULL, buf.length,
00436                                PROT_READ | PROT_WRITE, MAP_SHARED,
00437                                s->fd, buf.m.offset);
00438 
00439         if (s->buf_start[i] == MAP_FAILED) {
00440             av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));
00441             return AVERROR(errno);
00442         }
00443     }
00444 
00445     return 0;
00446 }
00447 
00448 static void mmap_release_buffer(AVPacket *pkt)
00449 {
00450     struct v4l2_buffer buf = { 0 };
00451     int res, fd;
00452     struct buff_data *buf_descriptor = pkt->priv;
00453 
00454     if (pkt->data == NULL)
00455         return;
00456 
00457     buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
00458     buf.memory = V4L2_MEMORY_MMAP;
00459     buf.index = buf_descriptor->index;
00460     fd = buf_descriptor->fd;
00461     av_free(buf_descriptor);
00462 
00463     res = v4l2_ioctl(fd, VIDIOC_QBUF, &buf);
00464     if (res < 0)
00465         av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
00466                strerror(errno));
00467 
00468     pkt->data = NULL;
00469     pkt->size = 0;
00470 }
00471 
00472 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
00473 static int64_t av_gettime_monotonic(void)
00474 {
00475     struct timespec tv;
00476 
00477     clock_gettime(CLOCK_MONOTONIC, &tv);
00478     return (int64_t)tv.tv_sec * 1000000 + tv.tv_nsec / 1000;
00479 }
00480 #endif
00481 
00482 static int init_convert_timestamp(AVFormatContext *ctx, int64_t ts)
00483 {
00484     struct video_data *s = ctx->priv_data;
00485     int64_t now;
00486 
00487     now = av_gettime();
00488     if (s->ts_mode == V4L_TS_ABS &&
00489         ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE) {
00490         av_log(ctx, AV_LOG_INFO, "Detected absolute timestamps\n");
00491         s->ts_mode = V4L_TS_CONVERT_READY;
00492         return 0;
00493     }
00494 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
00495     now = av_gettime_monotonic();
00496     if (s->ts_mode == V4L_TS_MONO2ABS ||
00497         (ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE)) {
00498         int64_t period = av_rescale_q(1, ctx->streams[0]->codec->time_base,
00499                                       AV_TIME_BASE_Q);
00500         av_log(ctx, AV_LOG_INFO, "Detected monotonic timestamps, converting\n");
00501         /* microseconds instead of seconds, MHz instead of Hz */
00502         s->timefilter = ff_timefilter_new(1, period, 1.0E-6);
00503         s->ts_mode = V4L_TS_CONVERT_READY;
00504         return 0;
00505     }
00506 #endif
00507     av_log(ctx, AV_LOG_ERROR, "Unknown timestamps\n");
00508     return AVERROR(EIO);
00509 }
00510 
00511 static int convert_timestamp(AVFormatContext *ctx, int64_t *ts)
00512 {
00513     struct video_data *s = ctx->priv_data;
00514 
00515     if (s->ts_mode) {
00516         int r = init_convert_timestamp(ctx, *ts);
00517         if (r < 0)
00518             return r;
00519     }
00520 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
00521     if (s->timefilter) {
00522         int64_t nowa = av_gettime();
00523         int64_t nowm = av_gettime_monotonic();
00524         ff_timefilter_update(s->timefilter, nowa, nowm - s->last_time_m);
00525         s->last_time_m = nowm;
00526         *ts = ff_timefilter_eval(s->timefilter, *ts - nowm);
00527     }
00528 #endif
00529     return 0;
00530 }
00531 
00532 static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
00533 {
00534     struct video_data *s = ctx->priv_data;
00535     struct v4l2_buffer buf = {
00536         .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
00537         .memory = V4L2_MEMORY_MMAP
00538     };
00539     struct buff_data *buf_descriptor;
00540     int res;
00541 
00542     /* FIXME: Some special treatment might be needed in case of loss of signal... */
00543     while ((res = v4l2_ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
00544     if (res < 0) {
00545         if (errno == EAGAIN) {
00546             pkt->size = 0;
00547             return AVERROR(EAGAIN);
00548         }
00549         av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n",
00550                strerror(errno));
00551 
00552         return AVERROR(errno);
00553     }
00554     av_assert0(buf.index < s->buffers);
00555 
00556     /* CPIA is a compressed format and we don't know the exact number of bytes
00557      * used by a frame, so set it here as the driver announces it.
00558      */
00559     if (ctx->video_codec_id == AV_CODEC_ID_CPIA)
00560         s->frame_size = buf.bytesused;
00561 
00562     if (s->frame_size > 0 && buf.bytesused != s->frame_size) {
00563         av_log(ctx, AV_LOG_ERROR,
00564                "The v4l2 frame is %d bytes, but %d bytes are expected\n",
00565                buf.bytesused, s->frame_size);
00566 
00567         return AVERROR_INVALIDDATA;
00568     }
00569 
00570     /* Image is at s->buff_start[buf.index] */
00571     pkt->data= s->buf_start[buf.index];
00572     pkt->size = buf.bytesused;
00573     pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec;
00574     res = convert_timestamp(ctx, &pkt->pts);
00575     if (res < 0)
00576         return res;
00577     pkt->destruct = mmap_release_buffer;
00578     buf_descriptor = av_malloc(sizeof(struct buff_data));
00579     if (buf_descriptor == NULL) {
00580         /* Something went wrong... Since av_malloc() failed, we cannot even
00581          * allocate a buffer for memcopying into it
00582          */
00583         av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");
00584         res = v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf);
00585 
00586         return AVERROR(ENOMEM);
00587     }
00588     buf_descriptor->fd = s->fd;
00589     buf_descriptor->index = buf.index;
00590     pkt->priv = buf_descriptor;
00591 
00592     return s->buf_len[buf.index];
00593 }
00594 
00595 static int mmap_start(AVFormatContext *ctx)
00596 {
00597     struct video_data *s = ctx->priv_data;
00598     enum v4l2_buf_type type;
00599     int i, res;
00600 
00601     for (i = 0; i < s->buffers; i++) {
00602         struct v4l2_buffer buf = {
00603             .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
00604             .index  = i,
00605             .memory = V4L2_MEMORY_MMAP
00606         };
00607 
00608         res = v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf);
00609         if (res < 0) {
00610             av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
00611                    strerror(errno));
00612 
00613             return AVERROR(errno);
00614         }
00615     }
00616 
00617     type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
00618     res = v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type);
00619     if (res < 0) {
00620         av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n",
00621                strerror(errno));
00622 
00623         return AVERROR(errno);
00624     }
00625 
00626     return 0;
00627 }
00628 
00629 static void mmap_close(struct video_data *s)
00630 {
00631     enum v4l2_buf_type type;
00632     int i;
00633 
00634     type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
00635     /* We do not check for the result, because we could
00636      * not do anything about it anyway...
00637      */
00638     v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);
00639     for (i = 0; i < s->buffers; i++) {
00640         v4l2_munmap(s->buf_start[i], s->buf_len[i]);
00641     }
00642     av_free(s->buf_start);
00643     av_free(s->buf_len);
00644 }
00645 
00646 static int v4l2_set_parameters(AVFormatContext *s1)
00647 {
00648     struct video_data *s = s1->priv_data;
00649     struct v4l2_input input = { 0 };
00650     struct v4l2_standard standard = { 0 };
00651     struct v4l2_streamparm streamparm = { 0 };
00652     struct v4l2_fract *tpf = &streamparm.parm.capture.timeperframe;
00653     AVRational framerate_q = { 0 };
00654     int i, ret;
00655 
00656     streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
00657 
00658     if (s->framerate &&
00659         (ret = av_parse_video_rate(&framerate_q, s->framerate)) < 0) {
00660         av_log(s1, AV_LOG_ERROR, "Could not parse framerate '%s'.\n",
00661                s->framerate);
00662         return ret;
00663     }
00664 
00665     /* set tv video input */
00666     input.index = s->channel;
00667     if (v4l2_ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
00668         av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl enum input failed:\n");
00669         return AVERROR(EIO);
00670     }
00671 
00672     av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set input_id: %d, input: %s\n",
00673             s->channel, input.name);
00674     if (v4l2_ioctl(s->fd, VIDIOC_S_INPUT, &input.index) < 0) {
00675         av_log(s1, AV_LOG_ERROR,
00676                "The V4L2 driver ioctl set input(%d) failed\n",
00677                 s->channel);
00678         return AVERROR(EIO);
00679     }
00680 
00681     if (s->standard) {
00682         av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s\n",
00683                s->standard);
00684         /* set tv standard */
00685         for(i=0;;i++) {
00686             standard.index = i;
00687             ret = v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard);
00688             if (ret < 0 || !av_strcasecmp(standard.name, s->standard))
00689                 break;
00690         }
00691         if (ret < 0) {
00692             av_log(s1, AV_LOG_ERROR, "Unknown standard '%s'\n", s->standard);
00693             return ret;
00694         }
00695 
00696         av_log(s1, AV_LOG_DEBUG,
00697                "The V4L2 driver set standard: %s, id: %"PRIu64"\n",
00698                s->standard, (uint64_t)standard.id);
00699         if (v4l2_ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
00700             av_log(s1, AV_LOG_ERROR,
00701                    "The V4L2 driver ioctl set standard(%s) failed\n",
00702                    s->standard);
00703             return AVERROR(EIO);
00704         }
00705     }
00706 
00707     if (framerate_q.num && framerate_q.den) {
00708         av_log(s1, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",
00709                framerate_q.den, framerate_q.num);
00710         tpf->numerator   = framerate_q.den;
00711         tpf->denominator = framerate_q.num;
00712 
00713         if (v4l2_ioctl(s->fd, VIDIOC_S_PARM, &streamparm) != 0) {
00714             av_log(s1, AV_LOG_ERROR,
00715                    "ioctl set time per frame(%d/%d) failed\n",
00716                    framerate_q.den, framerate_q.num);
00717             return AVERROR(EIO);
00718         }
00719 
00720         if (framerate_q.num != tpf->denominator ||
00721             framerate_q.den != tpf->numerator) {
00722             av_log(s1, AV_LOG_INFO,
00723                    "The driver changed the time per frame from "
00724                    "%d/%d to %d/%d\n",
00725                    framerate_q.den, framerate_q.num,
00726                    tpf->numerator, tpf->denominator);
00727         }
00728     } else {
00729         if (v4l2_ioctl(s->fd, VIDIOC_G_PARM, &streamparm) != 0) {
00730             av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_PARM): %s\n",
00731                    strerror(errno));
00732             return AVERROR(errno);
00733         }
00734     }
00735     s1->streams[0]->codec->time_base.den = tpf->denominator;
00736     s1->streams[0]->codec->time_base.num = tpf->numerator;
00737 
00738     return 0;
00739 }
00740 
00741 static uint32_t device_try_init(AVFormatContext *s1,
00742                                 enum PixelFormat pix_fmt,
00743                                 int *width,
00744                                 int *height,
00745                                 enum AVCodecID *codec_id)
00746 {
00747     uint32_t desired_format = fmt_ff2v4l(pix_fmt, s1->video_codec_id);
00748 
00749     if (desired_format == 0 ||
00750         device_init(s1, width, height, desired_format) < 0) {
00751         int i;
00752 
00753         desired_format = 0;
00754         for (i = 0; i<FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
00755             if (s1->video_codec_id == AV_CODEC_ID_NONE ||
00756                 fmt_conversion_table[i].codec_id == s1->video_codec_id) {
00757                 desired_format = fmt_conversion_table[i].v4l2_fmt;
00758                 if (device_init(s1, width, height, desired_format) >= 0) {
00759                     break;
00760                 }
00761                 desired_format = 0;
00762             }
00763         }
00764     }
00765 
00766     if (desired_format != 0) {
00767         *codec_id = fmt_v4l2codec(desired_format);
00768         av_assert0(*codec_id != AV_CODEC_ID_NONE);
00769     }
00770 
00771     return desired_format;
00772 }
00773 
00774 static int v4l2_read_header(AVFormatContext *s1)
00775 {
00776     struct video_data *s = s1->priv_data;
00777     AVStream *st;
00778     int res = 0;
00779     uint32_t desired_format;
00780     enum AVCodecID codec_id = AV_CODEC_ID_NONE;
00781     enum PixelFormat pix_fmt = PIX_FMT_NONE;
00782 
00783     st = avformat_new_stream(s1, NULL);
00784     if (!st) {
00785         res = AVERROR(ENOMEM);
00786         goto out;
00787     }
00788 
00789     s->fd = device_open(s1);
00790     if (s->fd < 0) {
00791         res = s->fd;
00792         goto out;
00793     }
00794 
00795     if (s->list_format) {
00796         list_formats(s1, s->fd, s->list_format);
00797         res = AVERROR_EXIT;
00798         goto out;
00799     }
00800 
00801     avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
00802 
00803     if (s->pixel_format) {
00804         AVCodec *codec = avcodec_find_decoder_by_name(s->pixel_format);
00805 
00806         if (codec)
00807             s1->video_codec_id = codec->id;
00808 
00809         pix_fmt = av_get_pix_fmt(s->pixel_format);
00810 
00811         if (pix_fmt == PIX_FMT_NONE && !codec) {
00812             av_log(s1, AV_LOG_ERROR, "No such input format: %s.\n",
00813                    s->pixel_format);
00814 
00815             res = AVERROR(EINVAL);
00816             goto out;
00817         }
00818     }
00819 
00820     if (!s->width && !s->height) {
00821         struct v4l2_format fmt;
00822 
00823         av_log(s1, AV_LOG_VERBOSE,
00824                "Querying the device for the current frame size\n");
00825         fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
00826         if (v4l2_ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
00827             av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n",
00828                    strerror(errno));
00829             res = AVERROR(errno);
00830             goto out;
00831         }
00832 
00833         s->width  = fmt.fmt.pix.width;
00834         s->height = fmt.fmt.pix.height;
00835         av_log(s1, AV_LOG_VERBOSE,
00836                "Setting frame size to %dx%d\n", s->width, s->height);
00837     }
00838 
00839     desired_format = device_try_init(s1, pix_fmt, &s->width, &s->height,
00840                                      &codec_id);
00841 
00842     /* If no pixel_format was specified, the codec_id was not known up
00843      * until now. Set video_codec_id in the context, as codec_id will
00844      * not be available outside this function
00845      */
00846     if (codec_id != AV_CODEC_ID_NONE && s1->video_codec_id == AV_CODEC_ID_NONE)
00847         s1->video_codec_id = codec_id;
00848 
00849     if (desired_format == 0) {
00850         av_log(s1, AV_LOG_ERROR, "Cannot find a proper format for "
00851                "codec_id %d, pix_fmt %d.\n", s1->video_codec_id, pix_fmt);
00852         v4l2_close(s->fd);
00853 
00854         res = AVERROR(EIO);
00855         goto out;
00856     }
00857     if ((res = av_image_check_size(s->width, s->height, 0, s1)) < 0)
00858         goto out;
00859 
00860     s->frame_format = desired_format;
00861 
00862     if ((res = v4l2_set_parameters(s1)) < 0)
00863         goto out;
00864 
00865     st->codec->pix_fmt = fmt_v4l2ff(desired_format, codec_id);
00866     s->frame_size =
00867         avpicture_get_size(st->codec->pix_fmt, s->width, s->height);
00868 
00869     if ((res = mmap_init(s1)) ||
00870         (res = mmap_start(s1)) < 0) {
00871         v4l2_close(s->fd);
00872         goto out;
00873     }
00874 
00875     s->top_field_first = first_field(s->fd);
00876 
00877     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00878     st->codec->codec_id = codec_id;
00879     if (codec_id == AV_CODEC_ID_RAWVIDEO)
00880         st->codec->codec_tag =
00881             avcodec_pix_fmt_to_codec_tag(st->codec->pix_fmt);
00882     if (desired_format == V4L2_PIX_FMT_YVU420)
00883         st->codec->codec_tag = MKTAG('Y', 'V', '1', '2');
00884     st->codec->width = s->width;
00885     st->codec->height = s->height;
00886     st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8;
00887 
00888 out:
00889     return res;
00890 }
00891 
00892 static int v4l2_read_packet(AVFormatContext *s1, AVPacket *pkt)
00893 {
00894     struct video_data *s = s1->priv_data;
00895     AVFrame *frame = s1->streams[0]->codec->coded_frame;
00896     int res;
00897 
00898     av_init_packet(pkt);
00899     if ((res = mmap_read_frame(s1, pkt)) < 0) {
00900         return res;
00901     }
00902 
00903     if (frame && s->interlaced) {
00904         frame->interlaced_frame = 1;
00905         frame->top_field_first = s->top_field_first;
00906     }
00907 
00908     return pkt->size;
00909 }
00910 
00911 static int v4l2_read_close(AVFormatContext *s1)
00912 {
00913     struct video_data *s = s1->priv_data;
00914 
00915     mmap_close(s);
00916 
00917     v4l2_close(s->fd);
00918     return 0;
00919 }
00920 
00921 #define OFFSET(x) offsetof(struct video_data, x)
00922 #define DEC AV_OPT_FLAG_DECODING_PARAM
00923 
00924 static const AVOption options[] = {
00925     { "standard",     "TV standard, used only by analog frame grabber",            OFFSET(standard),     AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0,       DEC },
00926     { "channel",      "TV channel, used only by frame grabber",                    OFFSET(channel),      AV_OPT_TYPE_INT,    {.i64 = 0 },    0, INT_MAX, DEC },
00927     { "video_size",   "A string describing frame size, such as 640x480 or hd720.", OFFSET(width),        AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL},  0, 0,       DEC },
00928     { "pixel_format", "Preferred pixel format",                                    OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       DEC },
00929     { "input_format", "Preferred pixel format (for raw video) or codec name",      OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       DEC },
00930     { "framerate",    "",                                                          OFFSET(framerate),    AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,       DEC },
00931     { "list_formats", "List available formats and exit",                           OFFSET(list_format),  AV_OPT_TYPE_INT,    {.i64 = 0 },  0, INT_MAX, DEC, "list_formats" },
00932     { "all",          "Show all available formats",                                OFFSET(list_format),  AV_OPT_TYPE_CONST,  {.i64 = V4L_ALLFORMATS  },    0, INT_MAX, DEC, "list_formats" },
00933     { "raw",          "Show only non-compressed formats",                          OFFSET(list_format),  AV_OPT_TYPE_CONST,  {.i64 = V4L_RAWFORMATS  },    0, INT_MAX, DEC, "list_formats" },
00934     { "compressed",   "Show only compressed formats",                              OFFSET(list_format),  AV_OPT_TYPE_CONST,  {.i64 = V4L_COMPFORMATS },    0, INT_MAX, DEC, "list_formats" },
00935     { "timestamps",   "Kind of timestamps for grabbed frames",                     OFFSET(ts_mode),      AV_OPT_TYPE_INT,    {.i64 = 0 }, 0, 2, DEC, "timestamps" },
00936     { "default",      "Use timestamps from the kernel",                            OFFSET(ts_mode),      AV_OPT_TYPE_CONST,  {.i64 = V4L_TS_DEFAULT  }, 0, 2, DEC, "timestamps" },
00937     { "abs",          "Use absolute timestamps (wall clock)",                      OFFSET(ts_mode),      AV_OPT_TYPE_CONST,  {.i64 = V4L_TS_ABS      }, 0, 2, DEC, "timestamps" },
00938     { "mono2abs",     "Force conversion from monotonic to absolute timestamps",    OFFSET(ts_mode),      AV_OPT_TYPE_CONST,  {.i64 = V4L_TS_MONO2ABS }, 0, 2, DEC, "timestamps" },
00939     { "ts",           "Kind of timestamps for grabbed frames",                     OFFSET(ts_mode),      AV_OPT_TYPE_INT,    {.i64 = 0 }, 0, 2, DEC, "timestamps" },
00940     { NULL },
00941 };
00942 
00943 static const AVClass v4l2_class = {
00944     .class_name = "V4L2 indev",
00945     .item_name  = av_default_item_name,
00946     .option     = options,
00947     .version    = LIBAVUTIL_VERSION_INT,
00948 };
00949 
00950 AVInputFormat ff_v4l2_demuxer = {
00951     .name           = "video4linux2,v4l2",
00952     .long_name      = NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"),
00953     .priv_data_size = sizeof(struct video_data),
00954     .read_header    = v4l2_read_header,
00955     .read_packet    = v4l2_read_packet,
00956     .read_close     = v4l2_read_close,
00957     .flags          = AVFMT_NOFILE,
00958     .priv_class     = &v4l2_class,
00959 };