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

  */
 
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <time.h>
 #include <linux/fb.h>
 

 #include "libavutil/internal.h"

 #include "libavutil/log.h"

 #include "libavutil/mem.h"

 #include "libavutil/opt.h"

 #include "libavutil/time.h"

 #include "libavutil/parseutils.h"

 #include "libavutil/pixdesc.h"

 #include "libavformat/internal.h"

 #include "avdevice.h"
 #include "fbdev_common.h"

 typedef struct FBDevContext {

     AVClass *class;          ///< class for private options

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

     AVRational framerate_q;  ///< framerate

     int64_t time_frame;      ///< time for the next frame to output (in 1/1000000 units)
 
     int fd;                  ///< framebuffer device file descriptor

     int width, height;       ///< 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;
 

 static av_cold int fbdev_read_header(AVFormatContext *avctx)

 {
     FBDevContext *fbdev = avctx->priv_data;
     AVStream *st = NULL;

     enum AVPixelFormat pix_fmt;

     int ret, flags = O_RDONLY;
 

     if (!(st = avformat_new_stream(avctx, NULL)))

         return AVERROR(ENOMEM);

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

 
     /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
     if (avctx->flags & AVFMT_FLAG_NONBLOCK)
         flags |= O_NONBLOCK;
 

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

         ret = AVERROR(errno);
         av_log(avctx, AV_LOG_ERROR,
                "Could not open framebuffer device '%s': %s\n",

                avctx->filename, av_err2str(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", av_err2str(ret));

         goto fail;
     }
 
     if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
         ret = AVERROR(errno);
         av_log(avctx, AV_LOG_ERROR,

                "FBIOGET_FSCREENINFO: %s\n", av_err2str(ret));

         goto fail;
     }
 

     pix_fmt = ff_get_pixfmt_from_fb_varinfo(&fbdev->varinfo);

     if (pix_fmt == AV_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->height          = 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->height;

     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", av_err2str(ret));

         goto fail;
     }
 
     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

     st->codec->codec_id   = AV_CODEC_ID_RAWVIDEO;

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

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

     st->codec->pix_fmt    = pix_fmt;

     st->codec->time_base  = av_inv_q(fbdev->framerate_q);

     st->codec->bit_rate   =

         fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;

 
     av_log(avctx, AV_LOG_INFO,

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

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

            av_get_pix_fmt_name(pix_fmt),

            fbdev->framerate_q.num, fbdev->framerate_q.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->framerate_q);

             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", av_err2str(ret));

 
     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->height; i++) {

         memcpy(pout, pin, fbdev->frame_linesize);
         pin  += fbdev->fixinfo.line_length;
         pout += fbdev->frame_linesize;
     }
 
     return fbdev->frame_size;
 }
 

 static av_cold int fbdev_read_close(AVFormatContext *avctx)

 {
     FBDevContext *fbdev = avctx->priv_data;
 

     munmap(fbdev->data, fbdev->fixinfo.smem_len);

     close(fbdev->fd);
 
     return 0;
 }
 

 static int fbdev_get_device_list(AVFormatContext *s, AVDeviceInfoList *device_list)
 {
     return ff_fbdev_get_device_list(device_list);
 }
 

 #define OFFSET(x) offsetof(FBDevContext, x)
 #define DEC AV_OPT_FLAG_DECODING_PARAM
 static const AVOption options[] = {

     { "framerate","", OFFSET(framerate_q), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, DEC },

     { NULL },
 };
 
 static const AVClass fbdev_class = {
     .class_name = "fbdev indev",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,

     .category   = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,

 };
 

 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,

     .get_device_list = fbdev_get_device_list,

     .flags          = AVFMT_NOFILE,

     .priv_class     = &fbdev_class,

 };