[PATCH] Add Linux framebuffer device.

Stefano Sabatini stefano.sabatini-lala
Tue Jan 25 19:40:29 CET 2011


Based on a patch by Giliard B. de Freitas /com/gmail/giliarde.

See thread:
Subject: [FFmpeg-devel] Fwd: framebuffer device demuxer
Date: Sat, 23 May 2009 09:32:13 -0300
---
 Changelog                 |    1 +
 configure                 |    2 +
 doc/indevs.texi           |   18 ++++
 libavdevice/Makefile      |    1 +
 libavdevice/alldevices.c  |    1 +
 libavdevice/framebuffer.c |  216 +++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 239 insertions(+), 0 deletions(-)
 create mode 100644 libavdevice/framebuffer.c

diff --git a/Changelog b/Changelog
index 8b7efb6..1c9166e 100644
--- a/Changelog
+++ b/Changelog
@@ -74,6 +74,7 @@ version <next>:
 - Lagarith decoder
 - ffmpeg -copytb option added
 - IVF muxer added
+- Linux framebuffer input device added
 
 
 version 0.6:
diff --git a/configure b/configure
index 001f00a..e75ad41 100755
--- a/configure
+++ b/configure
@@ -1387,6 +1387,7 @@ alsa_indev_deps="alsa_asoundlib_h snd_pcm_htimestamp"
 alsa_outdev_deps="alsa_asoundlib_h"
 bktr_indev_deps_any="dev_bktr_ioctl_bt848_h machine_ioctl_bt848_h dev_video_bktr_ioctl_bt848_h dev_ic_bt8xx_h"
 dv1394_indev_deps="dv1394 dv_demuxer"
+framebuffer_indev_deps="linux_fb_h"
 jack_indev_deps="jack_jack_h"
 libdc1394_indev_deps="libdc1394"
 oss_indev_deps_any="soundcard_h sys_soundcard_h"
@@ -2848,6 +2849,7 @@ if enabled network; then
     fi
 fi
 
+check_header linux/fb.h
 check_header linux/videodev.h
 check_header linux/videodev2.h
 check_header sys/videoio.h
diff --git a/doc/indevs.texi b/doc/indevs.texi
index 8e862ff..e9b1bea 100644
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -59,6 +59,24 @@ BSD video input device.
 
 Linux DV 1394 input device.
 
+ at section framebuffer
+
+Linux framebuffer input device.
+
+The name of the framebuffer device to read is a file device node,
+usually @file{/dev/fb0}.
+
+For example, to record from the framebuffer device /dev/fb0 with
+ at file{ffmpeg}:
+ at example
+ffmpeg -f framebuffer -r 10 -i /dev/fb0 out.avi
+ at end example
+
+You can take a single screenshot image with the command:
+ at example
+ffmpeg -f framebuffer -vframes 1 -r 1 -i /dev/fb0 screenshot.jpeg
+ at end example
+
 @section jack
 
 JACK input device.
diff --git a/libavdevice/Makefile b/libavdevice/Makefile
index 1c0630b..f5afeb2 100644
--- a/libavdevice/Makefile
+++ b/libavdevice/Makefile
@@ -14,6 +14,7 @@ OBJS-$(CONFIG_ALSA_OUTDEV)               += alsa-audio-common.o \
                                             alsa-audio-enc.o
 OBJS-$(CONFIG_BKTR_INDEV)                += bktr.o
 OBJS-$(CONFIG_DV1394_INDEV)              += dv1394.o
+OBJS-$(CONFIG_FRAMEBUFFER_INDEV)         += framebuffer.o
 OBJS-$(CONFIG_JACK_INDEV)                += jack_audio.o
 OBJS-$(CONFIG_OSS_INDEV)                 += oss_audio.o
 OBJS-$(CONFIG_OSS_OUTDEV)                += oss_audio.o
diff --git a/libavdevice/alldevices.c b/libavdevice/alldevices.c
index de3bc82..4e79467 100644
--- a/libavdevice/alldevices.c
+++ b/libavdevice/alldevices.c
@@ -42,6 +42,7 @@ void avdevice_register_all(void)
     REGISTER_INOUTDEV (ALSA, alsa);
     REGISTER_INDEV    (BKTR, bktr);
     REGISTER_INDEV    (DV1394, dv1394);
+    REGISTER_INDEV    (FRAMEBUFFER, framebuffer);
     REGISTER_INDEV    (JACK, jack);
     REGISTER_INOUTDEV (OSS, oss);
     REGISTER_INDEV    (V4L2, v4l2);
diff --git a/libavdevice/framebuffer.c b/libavdevice/framebuffer.c
new file mode 100644
index 0000000..902744f
--- /dev/null
+++ b/libavdevice/framebuffer.c
@@ -0,0 +1,216 @@
+/*
+ * Copyright (c) 2010 Stefano Sabatini
+ * Copyright (c) 2009 Giliard B. de Freitas <giliarde at gmail.com>
+ * Copyright (C) 2002 Gunnar Monell <gmo at 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,
+ * based on code from fbgrab.c by Gunnar Monell.
+ */
+
+#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"
+
+typedef struct {
+    int frame_size;          ///< size in bytes of a grabbed frame
+    AVRational time_base;    ///< time base
+    int64_t time_frame;      ///< current time
+
+    int frame_linesize;      ///< linesize of the output frame
+    int linesize;            ///< linesize of the read framebuffer
+    int height;              ///< height of the grab frame
+    int width;               ///< width of the grab frame
+    int fd;                  ///< framebuffer device file descriptor
+
+    uint8_t *data;           ///< image data
+} FrameBufferContext;
+
+/**
+ * Initialize the framebuffer input device.
+ */
+av_cold static int framebuffer_read_header(AVFormatContext *avctx, AVFormatParameters *ap)
+{
+    FrameBufferContext *fb = avctx->priv_data;
+    struct fb_var_screeninfo fb_varinfo;
+    struct fb_fix_screeninfo fb_fixinfo;
+    AVStream *st = NULL;
+    enum PixelFormat pix_fmt;
+    int ret, bits_per_pixel, flags = O_RDONLY;
+
+    if (!(st = av_new_stream(avctx, 0)))
+        return AVERROR(ENOMEM);
+
+    if (avctx->flags & AVFMT_FLAG_NONBLOCK)
+        flags |= O_NONBLOCK;
+
+    if ((fb->fd = open(avctx->filename, flags)) == -1) {
+        ret = AVERROR(errno);
+        av_log(avctx, AV_LOG_ERROR, "Could not open framebuffer device '%s'.\n", avctx->filename);
+        goto fail;
+    }
+
+    if (ioctl(fb->fd, FBIOGET_VSCREENINFO, &fb_varinfo) < 0) {
+        ret = AVERROR(errno);
+        av_log(avctx, AV_LOG_ERROR, "FBIOGET_VSCREENINFO: %s\n", strerror(errno));
+        goto fail;
+    }
+
+    if (ioctl(fb->fd, FBIOGET_FSCREENINFO, &fb_fixinfo) < 0) {
+        ret = AVERROR(errno);
+        av_log(avctx, AV_LOG_ERROR, "FBIOGET_FSCREENINFO: %s\n", strerror(errno));
+        goto fail;
+    }
+
+    if (ap->time_base.den <= 0) {
+        ret = AVERROR(EINVAL);
+        av_log(avctx, AV_LOG_ERROR, "Invalid time base %d/%d\n", ap->time_base.num, ap->time_base.den);
+        goto fail;
+    }
+
+    av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
+
+    fb->width  = fb_varinfo.xres;
+    fb->height = fb_varinfo.yres;
+    bits_per_pixel = fb_varinfo.bits_per_pixel;
+
+    switch (bits_per_pixel) {
+    case  8: pix_fmt = PIX_FMT_PAL8  ; break;
+    case 15: pix_fmt = PIX_FMT_BGR555; break;
+    case 16: pix_fmt = PIX_FMT_RGB565; break;
+    case 24: pix_fmt = PIX_FMT_RGB24 ; break;
+    case 32: pix_fmt = PIX_FMT_RGB32 ; break;
+    default:
+        ret = AVERROR(EINVAL);
+        av_log(avctx, AV_LOG_ERROR, "Image with bits per pixel depth %d not supported.\n",
+               bits_per_pixel);
+        goto fail;
+    }
+
+    fb->frame_linesize = fb_varinfo.xres * ((bits_per_pixel + 7) >> 3);
+    fb->frame_size     = fb->frame_linesize * fb_varinfo.yres;
+    fb->linesize       = fb_fixinfo.line_length;
+    fb->time_base      = ap->time_base;
+    fb->time_frame     = av_gettime() / av_q2d(ap->time_base);
+    fb->data = mmap(NULL, fb_fixinfo.line_length * fb_varinfo.yres,
+                    PROT_READ, MAP_SHARED, fb->fd, 0);
+    if (fb->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      = fb->width;
+    st->codec->height     = fb->height;
+    st->codec->pix_fmt    = pix_fmt;
+    st->codec->time_base  = ap->time_base;
+    st->codec->bit_rate   = fb->frame_size / 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",
+           fb->width, fb->height, 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:
+    if (fb->fd >= 0)
+        close(fb->fd);
+    return ret;
+}
+
+/**
+ * Grab a frame from the frame buffer device.
+ *
+ * @param pkt packet holding the grabbed frame
+ * @return frame size in bytes
+ */
+static int framebuffer_read_packet(AVFormatContext *avctx, AVPacket *pkt)
+{
+    FrameBufferContext *fb = avctx->priv_data;
+    int64_t curtime, delay;
+    struct timespec ts;
+    int i, ret;
+    uint8_t *pin, *pout;
+
+    /* wait based on the frame rate */
+    while (1) {
+        curtime = av_gettime();
+        delay = curtime - fb->time_frame * av_q2d(fb->time_base);
+        if (delay >= 0) {
+            fb->time_frame += INT64_C(1000000) * av_q2d(fb->time_base);
+            break;
+        }
+        if (avctx->flags & AVFMT_FLAG_NONBLOCK)
+            return AVERROR(EAGAIN);
+        ts.tv_sec  =  delay / 1000000;
+        ts.tv_nsec = (delay % 1000000) * 1000;
+        nanosleep(&ts, NULL);
+    }
+
+    if ((ret = av_new_packet(pkt, fb->frame_size)) < 0)
+        return ret;
+
+    pkt->pts = curtime;
+    pin  = fb->data;
+    pout = pkt->data;
+    for (i = 0; i < fb->height; i++) {
+        memcpy(pout, pin, fb->frame_linesize);
+        pin  += fb->linesize;
+        pout += fb->frame_linesize;
+    }
+
+    return fb->frame_size;
+}
+
+/**
+ * Close framebuffer input device.
+ *
+ * @return a negative value in case of errors, 0 otherwise
+ */
+av_cold static int framebuffer_read_close(AVFormatContext *avctx)
+{
+    FrameBufferContext *fb = avctx->priv_data;
+
+    munmap(fb->data, fb->frame_size);
+    close(fb->fd);
+
+    return 0;
+}
+
+AVInputFormat framebuffer_demuxer = {
+    .name           = "framebuffer",
+    .long_name      = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
+    .priv_data_size = sizeof(FrameBufferContext),
+    .read_header    = framebuffer_read_header,
+    .read_packet    = framebuffer_read_packet,
+    .read_close     = framebuffer_read_close,
+    .flags          = AVFMT_NOFILE,
+};
-- 
1.7.2.3


--UlVJffcvxoiEqYs2--



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