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ffmpeg / libavdevice / fbdev.c @ c6f95144

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/*
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 * Copyright (c) 2011 Stefano Sabatini
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 * Copyright (c) 2009 Giliard B. de Freitas <giliarde@gmail.com>
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 * Copyright (C) 2002 Gunnar Monell <gmo@linux.nu>
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 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * Linux framebuffer input device,
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 * inspired by code from fbgrab.c by Gunnar Monell.
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 * See also http://linux-fbdev.sourceforge.net/.
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 */
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/* #define DEBUG */
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <sys/time.h>
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#include <sys/mman.h>
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#include <time.h>
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#include <linux/fb.h>
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#include "libavutil/mem.h"
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#include "libavutil/pixdesc.h"
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#include "libavformat/avformat.h"
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struct rgb_pixfmt_map_entry {
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    int bits_per_pixel;
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    int red_offset, green_offset, blue_offset, alpha_offset;
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    enum PixelFormat pixfmt;
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};
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static struct rgb_pixfmt_map_entry rgb_pixfmt_map[] = {
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    // bpp, red_offset,  green_offset, blue_offset, alpha_offset, pixfmt
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    {  32,       0,           8,          16,           24,   PIX_FMT_RGBA  },
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    {  32,      16,           8,           0,           24,   PIX_FMT_BGRA  },
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    {  32,       8,          16,          24,            0,   PIX_FMT_ARGB  },
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    {  32,       3,           2,           8,            0,   PIX_FMT_ABGR  },
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    {  24,       0,           8,          16,            0,   PIX_FMT_RGB24 },
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    {  24,      16,           8,           0,            0,   PIX_FMT_BGR24 },
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};
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static enum PixelFormat get_pixfmt_from_fb_varinfo(struct fb_var_screeninfo *varinfo)
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{
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    int i;
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    for (i = 0; i < FF_ARRAY_ELEMS(rgb_pixfmt_map); i++) {
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        struct rgb_pixfmt_map_entry *entry = &rgb_pixfmt_map[i];
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        if (entry->bits_per_pixel == varinfo->bits_per_pixel &&
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            entry->red_offset     == varinfo->red.offset     &&
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            entry->green_offset   == varinfo->green.offset   &&
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            entry->blue_offset    == varinfo->blue.offset)
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            return entry->pixfmt;
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    }
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    return PIX_FMT_NONE;
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}
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typedef struct {
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    int frame_size;          ///< size in bytes of a grabbed frame
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    AVRational time_base;    ///< time base
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    int64_t time_frame;      ///< time for the next frame to output (in 1/1000000 units)
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    int fd;                  ///< framebuffer device file descriptor
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    int width, heigth;       ///< assumed frame resolution
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    int frame_linesize;      ///< linesize of the output frame, it is assumed to be constant
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    int bytes_per_pixel;
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    struct fb_var_screeninfo varinfo; ///< variable info;
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    struct fb_fix_screeninfo fixinfo; ///< fixed    info;
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    uint8_t *data;           ///< framebuffer data
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} FBDevContext;
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av_cold static int fbdev_read_header(AVFormatContext *avctx,
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                                     AVFormatParameters *ap)
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{
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    FBDevContext *fbdev = avctx->priv_data;
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    AVStream *st = NULL;
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    enum PixelFormat pix_fmt;
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    int ret, flags = O_RDONLY;
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    if (!(st = av_new_stream(avctx, 0)))
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        return AVERROR(ENOMEM);
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    av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
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    if (ap->time_base.den <= 0) {
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        av_log(avctx, AV_LOG_ERROR, "Invalid time base %d/%d\n",
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               ap->time_base.num, ap->time_base.den);
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        return AVERROR(EINVAL);
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    }
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    /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
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    if (avctx->flags & AVFMT_FLAG_NONBLOCK)
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        flags |= O_NONBLOCK;
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    if ((fbdev->fd = open(avctx->filename, flags)) == -1) {
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        ret = AVERROR(errno);
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        av_log(avctx, AV_LOG_ERROR,
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               "Could not open framebuffer device '%s': %s\n",
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               avctx->filename, strerror(ret));
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        return ret;
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    }
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    if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
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        ret = AVERROR(errno);
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        av_log(avctx, AV_LOG_ERROR,
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               "FBIOGET_VSCREENINFO: %s\n", strerror(errno));
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        goto fail;
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    }
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    if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
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        ret = AVERROR(errno);
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        av_log(avctx, AV_LOG_ERROR,
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               "FBIOGET_FSCREENINFO: %s\n", strerror(errno));
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        goto fail;
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    }
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    pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
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    if (pix_fmt == PIX_FMT_NONE) {
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        ret = AVERROR(EINVAL);
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        av_log(avctx, AV_LOG_ERROR,
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               "Framebuffer pixel format not supported.\n");
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        goto fail;
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    }
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    fbdev->width           = fbdev->varinfo.xres;
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    fbdev->heigth          = fbdev->varinfo.yres;
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    fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
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    fbdev->frame_linesize  = fbdev->width * fbdev->bytes_per_pixel;
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    fbdev->frame_size      = fbdev->frame_linesize * fbdev->heigth;
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    fbdev->time_base       = ap->time_base;
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    fbdev->time_frame      = AV_NOPTS_VALUE;
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    fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
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    if (fbdev->data == MAP_FAILED) {
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        ret = AVERROR(errno);
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        av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", strerror(errno));
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        goto fail;
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    }
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    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
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    st->codec->codec_id   = CODEC_ID_RAWVIDEO;
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    st->codec->width      = fbdev->width;
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    st->codec->height     = fbdev->heigth;
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    st->codec->pix_fmt    = pix_fmt;
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    st->codec->time_base  = ap->time_base;
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    st->codec->bit_rate   =
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        fbdev->width * fbdev->heigth * fbdev->bytes_per_pixel / av_q2d(ap->time_base) * 8;
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    av_log(avctx, AV_LOG_INFO,
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           "w:%d h:%d bpp:%d pixfmt:%s tb:%d/%d bit_rate:%d\n",
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           fbdev->width, fbdev->heigth, fbdev->varinfo.bits_per_pixel,
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           av_pix_fmt_descriptors[pix_fmt].name,
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           ap->time_base.num, ap->time_base.den,
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           st->codec->bit_rate);
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    return 0;
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fail:
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    close(fbdev->fd);
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    return ret;
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}
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static int fbdev_read_packet(AVFormatContext *avctx, AVPacket *pkt)
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{
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    FBDevContext *fbdev = avctx->priv_data;
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    int64_t curtime, delay;
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    struct timespec ts;
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    int i, ret;
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    uint8_t *pin, *pout;
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    if (fbdev->time_frame == AV_NOPTS_VALUE)
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        fbdev->time_frame = av_gettime();
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    /* wait based on the frame rate */
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    curtime = av_gettime();
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    delay = fbdev->time_frame - curtime;
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    av_dlog(avctx,
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            "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
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            fbdev->time_frame, curtime, delay);
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    if (delay > 0) {
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        if (avctx->flags & AVFMT_FLAG_NONBLOCK)
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            return AVERROR(EAGAIN);
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        ts.tv_sec  =  delay / 1000000;
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        ts.tv_nsec = (delay % 1000000) * 1000;
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        while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
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    }
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    /* compute the time of the next frame */
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    fbdev->time_frame += INT64_C(1000000) * av_q2d(fbdev->time_base);
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    if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
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        return ret;
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    /* refresh fbdev->varinfo, visible data position may change at each call */
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    if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
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        av_log(avctx, AV_LOG_WARNING,
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               "Error refreshing variable info: %s\n", strerror(errno));
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    pkt->pts = curtime;
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    /* compute visible data offset */
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    pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
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                        fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
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    pout = pkt->data;
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    // TODO it'd be nice if the lines were aligned
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    for (i = 0; i < fbdev->heigth; i++) {
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        memcpy(pout, pin, fbdev->frame_linesize);
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        pin  += fbdev->fixinfo.line_length;
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        pout += fbdev->frame_linesize;
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    }
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    return fbdev->frame_size;
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}
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av_cold static int fbdev_read_close(AVFormatContext *avctx)
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{
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    FBDevContext *fbdev = avctx->priv_data;
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    munmap(fbdev->data, fbdev->frame_size);
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    close(fbdev->fd);
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    return 0;
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}
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AVInputFormat ff_fbdev_demuxer = {
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    .name           = "fbdev",
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    .long_name      = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
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    .priv_data_size = sizeof(FBDevContext),
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    .read_header    = fbdev_read_header,
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    .read_packet    = fbdev_read_packet,
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    .read_close     = fbdev_read_close,
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    .flags          = AVFMT_NOFILE,
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};