[PATCH] Add Linux framebuffer input 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          |   24 +++++
 libavdevice/Makefile     |    1 +
 libavdevice/alldevices.c |    1 +
 libavdevice/linuxfb.c    |  240 ++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 269 insertions(+), 0 deletions(-)
 create mode 100644 libavdevice/linuxfb.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 a4d1711..a7e4b28 100755
--- a/configure
+++ b/configure
@@ -1395,6 +1395,7 @@ 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"
+linuxfb_indev_deps="linux_fb_h"
 jack_indev_deps="jack_jack_h"
 libdc1394_indev_deps="libdc1394"
 oss_indev_deps_any="soundcard_h sys_soundcard_h"
@@ -2863,6 +2864,7 @@ fi
 
 texi2html -version > /dev/null 2>&1 && enable texi2html || disable texi2html
 
+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..655529f 100644
--- a/doc/indevs.texi
+++ b/doc/indevs.texi
@@ -112,6 +112,30 @@ For more information read:
 
 IIDC1394 input device, based on libdc1394 and libraw1394.
 
+ at section linuxfb
+
+Linux framebuffer input device.
+
+The name of the framebuffer device to read is a file device node,
+usually @file{/dev/fb0}.
+
+For more detailed information related to the Linux framebuffer device
+read the file kernel/Documentation/fb/framebuffer.txt included in
+Linux.
+
+For example, to record from the framebuffer device /dev/fb0 with
+ at file{ffmpeg}:
+ at example
+ffmpeg -f linuxfb -r 10 -i /dev/fb0 out.avi
+ at end example
+
+You can take a single screenshot image with the command:
+ at example
+ffmpeg -f linuxfb -vframes 1 -r 1 -i /dev/fb0 screenshot.jpeg
+ at end example
+
+See also fbset(1).
+
 @section oss
 
 Open Sound System input device.
diff --git a/libavdevice/Makefile b/libavdevice/Makefile
index 1c0630b..7786adb 100644
--- a/libavdevice/Makefile
+++ b/libavdevice/Makefile
@@ -15,6 +15,7 @@ OBJS-$(CONFIG_ALSA_OUTDEV)               += alsa-audio-common.o \
 OBJS-$(CONFIG_BKTR_INDEV)                += bktr.o
 OBJS-$(CONFIG_DV1394_INDEV)              += dv1394.o
 OBJS-$(CONFIG_JACK_INDEV)                += jack_audio.o
+OBJS-$(CONFIG_LINUXFB_INDEV)             += linuxfb.o
 OBJS-$(CONFIG_OSS_INDEV)                 += oss_audio.o
 OBJS-$(CONFIG_OSS_OUTDEV)                += oss_audio.o
 OBJS-$(CONFIG_V4L2_INDEV)                += v4l2.o
diff --git a/libavdevice/alldevices.c b/libavdevice/alldevices.c
index ce06bf2..5aaa967 100644
--- a/libavdevice/alldevices.c
+++ b/libavdevice/alldevices.c
@@ -43,6 +43,7 @@ void avdevice_register_all(void)
     REGISTER_INDEV    (BKTR, bktr);
     REGISTER_INDEV    (DV1394, dv1394);
     REGISTER_INDEV    (JACK, jack);
+    REGISTER_INDEV    (LINUXFB, linuxfb);
     REGISTER_INOUTDEV (OSS, oss);
     REGISTER_INDEV    (V4L2, v4l2);
     REGISTER_INDEV    (V4L, v4l);
diff --git a/libavdevice/linuxfb.c b/libavdevice/linuxfb.c
new file mode 100644
index 0000000..71fa653
--- /dev/null
+++ b/libavdevice/linuxfb.c
@@ -0,0 +1,240 @@
+/*
+ * 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,
+ * inspired by code from fbgrab.c by Gunnar Monell.
+ */
+
+/* #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, r_offset,  g_offset, b_offset, a_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 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;           ///< framebuffer data
+    uint8_t *visible_data;   ///< framebuffer visible data
+} FrameBufferContext;
+
+av_cold static int linuxfb_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, bytes_per_pixel, 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);
+    }
+
+    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': %s\n",
+               avctx->filename, strerror(ret));
+        return ret;
+    }
+
+    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;
+    }
+
+    fb->width  = fb_varinfo.xres;
+    fb->height = fb_varinfo.yres;
+
+    pix_fmt = get_pixfmt_from_fb_varinfo(&fb_varinfo);
+    if (pix_fmt == PIX_FMT_NONE) {
+        ret = AVERROR(EINVAL);
+        av_log(avctx, AV_LOG_ERROR, "Framebuffer pixel format not supported.\n");
+        goto fail;
+    }
+
+    bytes_per_pixel    = (fb_varinfo.bits_per_pixel + 7) >> 3;
+    fb->frame_linesize = fb_varinfo.xres * bytes_per_pixel;
+    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_NOPTS_VALUE;
+    fb->data = mmap(NULL, fb_fixinfo.line_length * (fb_varinfo.yoffset + 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;
+    }
+    fb->visible_data = fb->data +
+        (fb_varinfo.xoffset + fb_fixinfo.line_length * fb_varinfo.yoffset) * bytes_per_pixel;
+
+    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, fb_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(fb->fd);
+    return ret;
+}
+
+static int linuxfb_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;
+
+    if (fb->time_frame == AV_NOPTS_VALUE)
+        fb->time_frame = av_gettime();
+
+    /* wait based on the frame rate */
+    while (1) {
+        curtime = av_gettime();
+        delay = fb->time_frame - curtime;
+#ifdef DEBUG
+        av_log(avctx, AV_LOG_DEBUG,
+               "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
+               fb->time_frame, curtime, delay);
+#endif
+        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->visible_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;
+}
+
+av_cold static int linuxfb_read_close(AVFormatContext *avctx)
+{
+    FrameBufferContext *fb = avctx->priv_data;
+
+    munmap(fb->data, fb->frame_size);
+    close(fb->fd);
+
+    return 0;
+}
+
+AVInputFormat ff_linuxfb_demuxer = {
+    .name           = "linuxfb",
+    .long_name      = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
+    .priv_data_size = sizeof(FrameBufferContext),
+    .read_header    = linuxfb_read_header,
+    .read_packet    = linuxfb_read_packet,
+    .read_close     = linuxfb_read_close,
+    .flags          = AVFMT_NOFILE,
+};
-- 
1.7.2.3


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