[FFmpeg-devel] Fwd: framebuffer device demuxer
Måns Rullgård
mans
Sun Jan 30 17:36:38 CET 2011
Stefano Sabatini <stefano.sabatini-lala at poste.it> writes:
> 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;
Come to think of it, O_NONBLOCK doesn't make sense on fbdev. AFAICT
it is ignored by the drivers.
> + 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;
You should mmap the entire framebuffer memory (as and query the current
display offset in read_packet(). Yes, I know you said it wasn't ready.
> + 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
av_dlog()
> + 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);
> + }
This loop is weird. The correct way is something like this:
ts = delay; /* details omitted */
while (nanosleep(&ts, &ts) && errno == EINTR);
> + 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
>
>
--
M?ns Rullg?rd
mans at mansr.com
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