PeerStreamer

/*

 * Copyright (c) 2011 Stefano Sabatini

 * Copyright (c) 2009 Giliard B. de Freitas <giliarde@gmail.com>

 * Copyright (C) 2002 Gunnar Monell <gmo@linux.nu>

 *

 * 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

 * Linux framebuffer input device,

 * inspired by code from fbgrab.c by Gunnar Monell.

 * See also http://linux-fbdev.sourceforge.net/.

 */

/* #define DEBUG */

#include <unistd.h>

#include <fcntl.h>

#include <sys/ioctl.h>

#include <sys/time.h>

#include <sys/mman.h>

#include <time.h>

#include <linux/fb.h>

#include "libavutil/mem.h"

#include "libavutil/pixdesc.h"

#include "libavformat/avformat.h"

struct rgb_pixfmt_map_entry {

    int bits_per_pixel;

    int red_offset, green_offset, blue_offset, alpha_offset;

    enum PixelFormat pixfmt;

};

static struct rgb_pixfmt_map_entry rgb_pixfmt_map[] = {

    // bpp, red_offset,  green_offset, blue_offset, alpha_offset, pixfmt

    {  32,       0,           8,          16,           24,   PIX_FMT_RGBA  },

    {  32,      16,           8,           0,           24,   PIX_FMT_BGRA  },

    {  32,       8,          16,          24,            0,   PIX_FMT_ARGB  },

    {  32,       3,           2,           8,            0,   PIX_FMT_ABGR  },

    {  24,       0,           8,          16,            0,   PIX_FMT_RGB24 },

    {  24,      16,           8,           0,            0,   PIX_FMT_BGR24 },

};

static enum PixelFormat

get_pixfmt_from_fb_varinfo(struct fb_var_screeninfo *varinfo)

{

    int i;

    for (i = 0; i < FF_ARRAY_ELEMS(rgb_pixfmt_map); i++) {

        struct rgb_pixfmt_map_entry *entry = &rgb_pixfmt_map[i];

        if (entry->bits_per_pixel == varinfo->bits_per_pixel &&

            entry->red_offset     == varinfo->red.offset     &&

            entry->green_offset   == varinfo->green.offset   &&

            entry->blue_offset    == varinfo->blue.offset)

            return entry->pixfmt;

    }

    return PIX_FMT_NONE;

}

typedef struct {

    int frame_size;          ///< size in bytes of a grabbed frame

    AVRational time_base;    ///< time base

    int64_t time_frame;      ///< time for the next frame to output (in 1/1000000 units)

    int fd;                  ///< framebuffer device file descriptor

    int width, heigth;       ///< assumed frame resolution

    int frame_linesize;      ///< linesize of the output frame, it is assumed to be constant

    int bytes_per_pixel;

    struct fb_var_screeninfo varinfo; ///< variable info;

    struct fb_fix_screeninfo fixinfo; ///< fixed    info;

    uint8_t *data;           ///< framebuffer data

} FBDevContext;

av_cold static int fbdev_read_header(AVFormatContext *avctx,

                                     AVFormatParameters *ap)

{

    FBDevContext *fbdev = avctx->priv_data;

    AVStream *st = NULL;

    enum PixelFormat pix_fmt;

    int ret, flags = O_RDONLY;

    if (!(st = av_new_stream(avctx, 0)))

        return AVERROR(ENOMEM);

    av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */

    if (ap->time_base.den <= 0) {

        av_log(avctx, AV_LOG_ERROR, "Invalid time base %d/%d\n",

               ap->time_base.num, ap->time_base.den);

        return AVERROR(EINVAL);

    }

    /* NONBLOCK is ignored by the fbdev driver, only set for consistency */

    if (avctx->flags & AVFMT_FLAG_NONBLOCK)

        flags |= O_NONBLOCK;

    if ((fbdev->fd = open(avctx->filename, flags)) == -1) {

        ret = AVERROR(errno);

        av_log(avctx, AV_LOG_ERROR,

               "Could not open framebuffer device '%s': %s\n",

               avctx->filename, strerror(ret));

        return ret;

    }

    if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {

        ret = AVERROR(errno);

        av_log(avctx, AV_LOG_ERROR,

               "FBIOGET_VSCREENINFO: %s\n", strerror(errno));

        goto fail;

    }

    if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {

        ret = AVERROR(errno);

        av_log(avctx, AV_LOG_ERROR,

               "FBIOGET_FSCREENINFO: %s\n", strerror(errno));

        goto fail;

    }

    pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);

    if (pix_fmt == PIX_FMT_NONE) {

        ret = AVERROR(EINVAL);

        av_log(avctx, AV_LOG_ERROR,

               "Framebuffer pixel format not supported.\n");

        goto fail;

    }

    fbdev->width           = fbdev->varinfo.xres;

    fbdev->heigth          = fbdev->varinfo.yres;

    fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;

    fbdev->frame_linesize  = fbdev->width * fbdev->bytes_per_pixel;

    fbdev->frame_size      = fbdev->frame_linesize * fbdev->heigth;

    fbdev->time_base       = ap->time_base;

    fbdev->time_frame      = AV_NOPTS_VALUE;

    fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);

    if (fbdev->data == MAP_FAILED) {

        ret = AVERROR(errno);

        av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", strerror(errno));

        goto fail;

    }

    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

    st->codec->codec_id   = CODEC_ID_RAWVIDEO;

    st->codec->width      = fbdev->width;

    st->codec->height     = fbdev->heigth;

    st->codec->pix_fmt    = pix_fmt;

    st->codec->time_base  = ap->time_base;

    st->codec->bit_rate   =

        fbdev->width * fbdev->heigth * fbdev->bytes_per_pixel / av_q2d(ap->time_base) * 8;

    av_log(avctx, AV_LOG_INFO,

           "w:%d h:%d bpp:%d pixfmt:%s tb:%d/%d bit_rate:%d\n",

           fbdev->width, fbdev->heigth, fbdev->varinfo.bits_per_pixel,

           av_pix_fmt_descriptors[pix_fmt].name,

           ap->time_base.num, ap->time_base.den,

           st->codec->bit_rate);

    return 0;

fail:

    close(fbdev->fd);

    return ret;

}

static int fbdev_read_packet(AVFormatContext *avctx, AVPacket *pkt)

{

    FBDevContext *fbdev = avctx->priv_data;

    int64_t curtime, delay;

    struct timespec ts;

    int i, ret;

    uint8_t *pin, *pout;

    if (fbdev->time_frame == AV_NOPTS_VALUE)

        fbdev->time_frame = av_gettime();

    /* wait based on the frame rate */

    while (1) {

        curtime = av_gettime();

        delay = fbdev->time_frame - curtime;

        av_dlog(avctx,

                "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",

                fbdev->time_frame, curtime, delay);

        if (delay <= 0) {

            fbdev->time_frame += INT64_C(1000000) * av_q2d(fbdev->time_base);

            break;

        }

        if (avctx->flags & AVFMT_FLAG_NONBLOCK)

            return AVERROR(EAGAIN);

        ts.tv_sec  =  delay / 1000000;

        ts.tv_nsec = (delay % 1000000) * 1000;

        while (nanosleep(&ts, &ts) < 0 && errno == EINTR);

    }

    if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)

        return ret;

    /* refresh fbdev->varinfo, visible data position may change at each call */

    if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)

        av_log(avctx, AV_LOG_WARNING,

               "Error refreshing variable info: %s\n", strerror(errno));

    pkt->pts = curtime;

    /* compute visible data offset */

    pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +

                        fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;

    pout = pkt->data;

    for (i = 0; i < fbdev->heigth; i++) {

        memcpy(pout, pin, fbdev->frame_linesize);

        pin  += fbdev->fixinfo.line_length;

        pout += fbdev->frame_linesize;

    }

    return fbdev->frame_size;

}

av_cold static int fbdev_read_close(AVFormatContext *avctx)

{

    FBDevContext *fbdev = avctx->priv_data;

    munmap(fbdev->data, fbdev->frame_size);

    close(fbdev->fd);

    return 0;

}

AVInputFormat ff_fbdev_demuxer = {

    .name           = "fbdev",

    .long_name      = NULL_IF_CONFIG_SMALL("Linux framebuffer"),

    .priv_data_size = sizeof(FBDevContext),

    .read_header    = fbdev_read_header,

    .read_packet    = fbdev_read_packet,

    .read_close     = fbdev_read_close,

    .flags          = AVFMT_NOFILE,

};