FFmpeg/libavdevice/fbdev.c
Anton Khirnov 9200514ad8 lavf: replace AVStream.codec with AVStream.codecpar
Currently, AVStream contains an embedded AVCodecContext instance, which
is used by demuxers to export stream parameters to the caller and by
muxers to receive stream parameters from the caller. It is also used
internally as the codec context that is passed to parsers.

In addition, it is also widely used by the callers as the decoding (when
demuxer) or encoding (when muxing) context, though this has been
officially discouraged since Libav 11.

There are multiple important problems with this approach:
    - the fields in AVCodecContext are in general one of
        * stream parameters
        * codec options
        * codec state
      However, it's not clear which ones are which. It is consequently
      unclear which fields are a demuxer allowed to set or a muxer allowed to
      read. This leads to erratic behaviour depending on whether decoding or
      encoding is being performed or not (and whether it uses the AVStream
      embedded codec context).
    - various synchronization issues arising from the fact that the same
      context is used by several different APIs (muxers/demuxers,
      parsers, bitstream filters and encoders/decoders) simultaneously, with
      there being no clear rules for who can modify what and the different
      processes being typically delayed with respect to each other.
    - avformat_find_stream_info() making it necessary to support opening
      and closing a single codec context multiple times, thus
      complicating the semantics of freeing various allocated objects in the
      codec context.

Those problems are resolved by replacing the AVStream embedded codec
context with a newly added AVCodecParameters instance, which stores only
the stream parameters exported by the demuxers or read by the muxers.
2016-02-23 17:01:58 +01:00

278 lines
9.5 KiB
C

/*
* 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 Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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/avformat.h"
#include "libavformat/internal.h"
struct rgb_pixfmt_map_entry {
int bits_per_pixel;
int red_offset, green_offset, blue_offset, alpha_offset;
enum AVPixelFormat pixfmt;
};
static struct rgb_pixfmt_map_entry rgb_pixfmt_map[] = {
// bpp, red_offset, green_offset, blue_offset, alpha_offset, pixfmt
{ 32, 0, 8, 16, 24, AV_PIX_FMT_RGBA },
{ 32, 16, 8, 0, 24, AV_PIX_FMT_BGRA },
{ 32, 8, 16, 24, 0, AV_PIX_FMT_ARGB },
{ 32, 3, 2, 8, 0, AV_PIX_FMT_ABGR },
{ 24, 0, 8, 16, 0, AV_PIX_FMT_RGB24 },
{ 24, 16, 8, 0, 0, AV_PIX_FMT_BGR24 },
{ 16, 11, 5, 0, 0, AV_PIX_FMT_RGB565 },
};
static enum AVPixelFormat 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 AV_PIX_FMT_NONE;
}
typedef struct FBDevContext {
AVClass *class; ///< class for private options
int frame_size; ///< size in bytes of a grabbed frame
AVRational framerate_q; ///< framerate
char *framerate; ///< framerate string set by a private option
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;
char errbuf[128];
ret = av_parse_video_rate(&fbdev->framerate_q, fbdev->framerate);
if (ret < 0) {
av_log(avctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n", fbdev->framerate);
return ret;
}
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_strerror(ret, errbuf, sizeof(errbuf));
av_log(avctx, AV_LOG_ERROR,
"Could not open framebuffer device '%s': %s\n",
avctx->filename, errbuf);
return ret;
}
if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
ret = AVERROR(errno);
av_strerror(ret, errbuf, sizeof(errbuf));
av_log(avctx, AV_LOG_ERROR,
"FBIOGET_VSCREENINFO: %s\n", errbuf);
goto fail;
}
if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
ret = AVERROR(errno);
av_strerror(ret, errbuf, sizeof(errbuf));
av_log(avctx, AV_LOG_ERROR,
"FBIOGET_FSCREENINFO: %s\n", errbuf);
goto fail;
}
pix_fmt = 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_strerror(ret, errbuf, sizeof(errbuf));
av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", errbuf);
goto fail;
}
st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;
st->codecpar->width = fbdev->width;
st->codecpar->height = fbdev->height;
st->codecpar->format = pix_fmt;
st->codecpar->bit_rate =
fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
st->avg_frame_rate = fbdev->framerate_q;
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->codecpar->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 */
curtime = av_gettime();
delay = fbdev->time_frame - curtime;
av_log(avctx, AV_LOG_TRACE,
"time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
fbdev->time_frame, curtime, delay);
if (delay > 0) {
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);
}
/* compute the time of the next frame */
fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
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) {
char errbuf[128];
av_strerror(AVERROR(errno), errbuf, sizeof(errbuf));
av_log(avctx, AV_LOG_WARNING,
"Error refreshing variable info: %s\n", errbuf);
}
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;
// TODO it'd be nice if the lines were aligned
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->frame_size);
close(fbdev->fd);
return 0;
}
#define OFFSET(x) offsetof(FBDevContext, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
{ "framerate","", OFFSET(framerate), AV_OPT_TYPE_STRING, {.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,
};
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,
.flags = AVFMT_NOFILE,
.priv_class = &fbdev_class,
};