FFmpeg coverage

GCC Code Coverage Report

Directory:	../../../ffmpeg/		Exec	Total	Coverage
File:	src/libavdevice/xcbgrab.c	Lines:	0	350	0.0 %
Date:	2020-08-14 10:39:37	Branches:	0	142	0.0 %


/*
 * XCB input grabber
 * Copyright (C) 2014 Luca Barbato <lu_zero@gentoo.org>
 *
 * 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
 */

#include "config.h"

#include <stdlib.h>
#include <xcb/xcb.h>

#if CONFIG_LIBXCB_XFIXES
#include <xcb/xfixes.h>
#endif

#if CONFIG_LIBXCB_SHM
#include <sys/shm.h>
#include <xcb/shm.h>
#endif

#if CONFIG_LIBXCB_SHAPE
#include <xcb/shape.h>
#endif

#include "libavutil/internal.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/time.h"

#include "libavformat/avformat.h"
#include "libavformat/internal.h"

typedef struct XCBGrabContext {
    const AVClass *class;

    xcb_connection_t *conn;
    xcb_screen_t *screen;
    xcb_window_t window;
#if CONFIG_LIBXCB_SHM
    AVBufferPool *shm_pool;
#endif
    int64_t time_frame;
    AVRational time_base;
    int64_t frame_duration;

    int x, y;
    int width, height;
    int frame_size;
    int bpp;

    int draw_mouse;
    int follow_mouse;
    int show_region;
    int region_border;
    int centered;

    const char *framerate;

    int has_shm;
} XCBGrabContext;

#define FOLLOW_CENTER -1

#define OFFSET(x) offsetof(XCBGrabContext, x)
#define D AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
    { "x", "Initial x coordinate.", OFFSET(x), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
    { "y", "Initial y coordinate.", OFFSET(y), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
    { "grab_x", "Initial x coordinate.", OFFSET(x), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
    { "grab_y", "Initial y coordinate.", OFFSET(y), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
    { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL }, 0, 0, D },
    { "framerate", "", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "ntsc" }, 0, 0, D },
    { "draw_mouse", "Draw the mouse pointer.", OFFSET(draw_mouse), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, D },
    { "follow_mouse", "Move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region.",
      OFFSET(follow_mouse), AV_OPT_TYPE_INT, { .i64 = 0 },  FOLLOW_CENTER, INT_MAX, D, "follow_mouse" },
    { "centered", "Keep the mouse pointer at the center of grabbing region when following.", 0, AV_OPT_TYPE_CONST, { .i64 = -1 }, INT_MIN, INT_MAX, D, "follow_mouse" },
    { "show_region", "Show the grabbing region.", OFFSET(show_region), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, D },
    { "region_border", "Set the region border thickness.", OFFSET(region_border), AV_OPT_TYPE_INT, { .i64 = 3 }, 1, 128, D },
    { NULL },
};

static const AVClass xcbgrab_class = {
    .class_name = "xcbgrab indev",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
    .category   = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
};

static int xcbgrab_reposition(AVFormatContext *s,
                              xcb_query_pointer_reply_t *p,
                              xcb_get_geometry_reply_t *geo)
{
    XCBGrabContext *c = s->priv_data;
    int x = c->x, y = c->y;
    int w = c->width, h = c->height, f = c->follow_mouse;
    int p_x, p_y;

    if (!p || !geo)
        return AVERROR(EIO);

    p_x = p->win_x;
    p_y = p->win_y;

    if (f == FOLLOW_CENTER) {
        x = p_x - w / 2;
        y = p_y - h / 2;
    } else {
        int left   = x + f;
        int right  = x + w - f;
        int top    = y + f;
        int bottom = y + h - f;
        if (p_x > right) {
            x += p_x - right;
        } else if (p_x < left) {
            x -= left - p_x;
        }
        if (p_y > bottom) {
            y += p_y - bottom;
        } else if (p_y < top) {
            y -= top - p_y;
        }
    }

    c->x = FFMIN(FFMAX(0, x), geo->width  - w);
    c->y = FFMIN(FFMAX(0, y), geo->height - h);

    return 0;
}

static void xcbgrab_image_reply_free(void *opaque, uint8_t *data)
{
    free(opaque);
}

static int xcbgrab_frame(AVFormatContext *s, AVPacket *pkt)
{
    XCBGrabContext *c = s->priv_data;
    xcb_get_image_cookie_t iq;
    xcb_get_image_reply_t *img;
    xcb_drawable_t drawable = c->screen->root;
    xcb_generic_error_t *e = NULL;
    uint8_t *data;
    int length;

    iq  = xcb_get_image(c->conn, XCB_IMAGE_FORMAT_Z_PIXMAP, drawable,
                        c->x, c->y, c->width, c->height, ~0);

    img = xcb_get_image_reply(c->conn, iq, &e);

    if (e) {
        av_log(s, AV_LOG_ERROR,
               "Cannot get the image data "
               "event_error: response_type:%u error_code:%u "
               "sequence:%u resource_id:%u minor_code:%u major_code:%u.\n",
               e->response_type, e->error_code,
               e->sequence, e->resource_id, e->minor_code, e->major_code);
        free(e);
        return AVERROR(EACCES);
    }

    if (!img)
        return AVERROR(EAGAIN);

    data   = xcb_get_image_data(img);
    length = xcb_get_image_data_length(img);

    av_init_packet(pkt);

    pkt->buf = av_buffer_create(data, length, xcbgrab_image_reply_free, img, 0);
    if (!pkt->buf) {
        free(img);
        return AVERROR(ENOMEM);
    }

    pkt->data = data;
    pkt->size = length;

    return 0;
}

static int64_t wait_frame(AVFormatContext *s, AVPacket *pkt)
{
    XCBGrabContext *c = s->priv_data;
    int64_t curtime, delay;

    c->time_frame += c->frame_duration;

    for (;;) {
        curtime = av_gettime();
        delay   = c->time_frame - curtime;
        if (delay <= 0)
            break;
        av_usleep(delay);
    }

    return curtime;
}

#if CONFIG_LIBXCB_SHM
static int check_shm(xcb_connection_t *conn)
{
    xcb_shm_query_version_cookie_t cookie = xcb_shm_query_version(conn);
    xcb_shm_query_version_reply_t *reply;

    reply = xcb_shm_query_version_reply(conn, cookie, NULL);
    if (reply) {
        free(reply);
        return 1;
    }

    return 0;
}

static void free_shm_buffer(void *opaque, uint8_t *data)
{
    shmdt(data);
}

static AVBufferRef *allocate_shm_buffer(void *opaque, int size)
{
    xcb_connection_t *conn = opaque;
    xcb_shm_seg_t segment;
    AVBufferRef *ref;
    uint8_t *data;
    int id;

    id = shmget(IPC_PRIVATE, size, IPC_CREAT | 0777);
    if (id == -1)
        return NULL;

    segment = xcb_generate_id(conn);
    xcb_shm_attach(conn, segment, id, 0);
    data = shmat(id, NULL, 0);
    shmctl(id, IPC_RMID, 0);
    if ((intptr_t)data == -1 || !data)
        return NULL;

    ref = av_buffer_create(data, size, free_shm_buffer, (void *)(ptrdiff_t)segment, 0);
    if (!ref)
        shmdt(data);

    return ref;
}

static int xcbgrab_frame_shm(AVFormatContext *s, AVPacket *pkt)
{
    XCBGrabContext *c = s->priv_data;
    xcb_shm_get_image_cookie_t iq;
    xcb_shm_get_image_reply_t *img;
    xcb_drawable_t drawable = c->screen->root;
    xcb_generic_error_t *e = NULL;
    AVBufferRef *buf;
    xcb_shm_seg_t segment;

    buf = av_buffer_pool_get(c->shm_pool);
    if (!buf) {
        av_log(s, AV_LOG_ERROR, "Could not get shared memory buffer.\n");
        return AVERROR(ENOMEM);
    }
    segment = (xcb_shm_seg_t)av_buffer_pool_buffer_get_opaque(buf);

    iq = xcb_shm_get_image(c->conn, drawable,
                           c->x, c->y, c->width, c->height, ~0,
                           XCB_IMAGE_FORMAT_Z_PIXMAP, segment, 0);
    img = xcb_shm_get_image_reply(c->conn, iq, &e);

    xcb_flush(c->conn);

    if (e) {
        av_log(s, AV_LOG_ERROR,
               "Cannot get the image data "
               "event_error: response_type:%u error_code:%u "
               "sequence:%u resource_id:%u minor_code:%u major_code:%u.\n",
               e->response_type, e->error_code,
               e->sequence, e->resource_id, e->minor_code, e->major_code);

        free(e);
        av_buffer_unref(&buf);
        return AVERROR(EACCES);
    }

    free(img);

    av_init_packet(pkt);

    pkt->buf = buf;
    pkt->data = buf->data;
    pkt->size = c->frame_size;

    return 0;
}
#endif /* CONFIG_LIBXCB_SHM */

#if CONFIG_LIBXCB_XFIXES
static int check_xfixes(xcb_connection_t *conn)
{
    xcb_xfixes_query_version_cookie_t cookie;
    xcb_xfixes_query_version_reply_t *reply;

    cookie = xcb_xfixes_query_version(conn, XCB_XFIXES_MAJOR_VERSION,
                                      XCB_XFIXES_MINOR_VERSION);
    reply  = xcb_xfixes_query_version_reply(conn, cookie, NULL);

    if (reply) {
        free(reply);
        return 1;
    }
    return 0;
}

#define BLEND(target, source, alpha) \
    (target) + ((source) * (255 - (alpha)) + 255 / 2) / 255

static void xcbgrab_draw_mouse(AVFormatContext *s, AVPacket *pkt,
                               xcb_query_pointer_reply_t *p,
                               xcb_get_geometry_reply_t *geo)
{
    XCBGrabContext *gr = s->priv_data;
    uint32_t *cursor;
    uint8_t *image = pkt->data;
    int stride     = gr->bpp / 8;
    xcb_xfixes_get_cursor_image_cookie_t cc;
    xcb_xfixes_get_cursor_image_reply_t *ci;
    int cx, cy, x, y, w, h, c_off, i_off;

    cc = xcb_xfixes_get_cursor_image(gr->conn);
    ci = xcb_xfixes_get_cursor_image_reply(gr->conn, cc, NULL);
    if (!ci)
        return;

    cursor = xcb_xfixes_get_cursor_image_cursor_image(ci);
    if (!cursor)
        return;

    cx = ci->x - ci->xhot;
    cy = ci->y - ci->yhot;

    x = FFMAX(cx, gr->x);
    y = FFMAX(cy, gr->y);

    w = FFMIN(cx + ci->width,  gr->x + gr->width)  - x;
    h = FFMIN(cy + ci->height, gr->y + gr->height) - y;

    c_off = x - cx;
    i_off = x - gr->x;

    cursor += (y - cy) * ci->width;
    image  += (y - gr->y) * gr->width * stride;

    for (y = 0; y < h; y++) {
        cursor += c_off;
        image  += i_off * stride;
        for (x = 0; x < w; x++, cursor++, image += stride) {
            int r, g, b, a;

            r =  *cursor        & 0xff;
            g = (*cursor >>  8) & 0xff;
            b = (*cursor >> 16) & 0xff;
            a = (*cursor >> 24) & 0xff;

            if (!a)
                continue;

            if (a == 255) {
                image[0] = r;
                image[1] = g;
                image[2] = b;
            } else {
                image[0] = BLEND(r, image[0], a);
                image[1] = BLEND(g, image[1], a);
                image[2] = BLEND(b, image[2], a);
            }

        }
        cursor +=  ci->width - w - c_off;
        image  += (gr->width - w - i_off) * stride;
    }

    free(ci);
}
#endif /* CONFIG_LIBXCB_XFIXES */

static void xcbgrab_update_region(AVFormatContext *s)
{
    XCBGrabContext *c     = s->priv_data;
    const uint32_t args[] = { c->x - c->region_border,
                              c->y - c->region_border };

    xcb_configure_window(c->conn,
                         c->window,
                         XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y,
                         args);
}

static int xcbgrab_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    XCBGrabContext *c = s->priv_data;
    xcb_query_pointer_cookie_t pc;
    xcb_get_geometry_cookie_t gc;
    xcb_query_pointer_reply_t *p  = NULL;
    xcb_get_geometry_reply_t *geo = NULL;
    int ret = 0;
    int64_t pts;

    pts = wait_frame(s, pkt);

    if (c->follow_mouse || c->draw_mouse) {
        pc  = xcb_query_pointer(c->conn, c->screen->root);
        gc  = xcb_get_geometry(c->conn, c->screen->root);
        p   = xcb_query_pointer_reply(c->conn, pc, NULL);
        geo = xcb_get_geometry_reply(c->conn, gc, NULL);
    }

    if (c->follow_mouse && p->same_screen)
        xcbgrab_reposition(s, p, geo);

    if (c->show_region)
        xcbgrab_update_region(s);

#if CONFIG_LIBXCB_SHM
    if (c->has_shm && xcbgrab_frame_shm(s, pkt) < 0) {
        av_log(s, AV_LOG_WARNING, "Continuing without shared memory.\n");
        c->has_shm = 0;
    }
#endif
    if (!c->has_shm)
        ret = xcbgrab_frame(s, pkt);
    pkt->dts = pkt->pts = pts;
    pkt->duration = c->frame_duration;

#if CONFIG_LIBXCB_XFIXES
    if (ret >= 0 && c->draw_mouse && p->same_screen)
        xcbgrab_draw_mouse(s, pkt, p, geo);
#endif

    free(p);
    free(geo);

    return ret;
}

static av_cold int xcbgrab_read_close(AVFormatContext *s)
{
    XCBGrabContext *ctx = s->priv_data;

#if CONFIG_LIBXCB_SHM
    av_buffer_pool_uninit(&ctx->shm_pool);
#endif

    xcb_disconnect(ctx->conn);

    return 0;
}

static xcb_screen_t *get_screen(const xcb_setup_t *setup, int screen_num)
{
    xcb_screen_iterator_t it = xcb_setup_roots_iterator(setup);
    xcb_screen_t *screen     = NULL;

    for (; it.rem > 0; xcb_screen_next (&it)) {
        if (!screen_num) {
            screen = it.data;
            break;
        }

        screen_num--;
    }

    return screen;
}

static int pixfmt_from_pixmap_format(AVFormatContext *s, int depth,
                                     int *pix_fmt, int *bpp)
{
    XCBGrabContext *c        = s->priv_data;
    const xcb_setup_t *setup = xcb_get_setup(c->conn);
    const xcb_format_t *fmt  = xcb_setup_pixmap_formats(setup);
    int length               = xcb_setup_pixmap_formats_length(setup);

    *pix_fmt = 0;

    while (length--) {
        if (fmt->depth == depth) {
            switch (depth) {
            case 32:
                if (fmt->bits_per_pixel == 32)
                    *pix_fmt = AV_PIX_FMT_0RGB;
                break;
            case 24:
                if (fmt->bits_per_pixel == 32)
                    *pix_fmt = AV_PIX_FMT_0RGB32;
                else if (fmt->bits_per_pixel == 24)
                    *pix_fmt = AV_PIX_FMT_RGB24;
                break;
            case 16:
                if (fmt->bits_per_pixel == 16)
                    *pix_fmt = AV_PIX_FMT_RGB565;
                break;
            case 15:
                if (fmt->bits_per_pixel == 16)
                    *pix_fmt = AV_PIX_FMT_RGB555;
                break;
            case 8:
                if (fmt->bits_per_pixel == 8)
                    *pix_fmt = AV_PIX_FMT_RGB8;
                break;
            }
        }

        if (*pix_fmt) {
            *bpp        = fmt->bits_per_pixel;
            return 0;
        }

        fmt++;
    }
    avpriv_report_missing_feature(s, "Mapping this pixmap format");

    return AVERROR_PATCHWELCOME;
}

static int create_stream(AVFormatContext *s)
{
    XCBGrabContext *c = s->priv_data;
    AVStream *st      = avformat_new_stream(s, NULL);
    xcb_get_geometry_cookie_t gc;
    xcb_get_geometry_reply_t *geo;
    int64_t frame_size_bits;
    int ret;

    if (!st)
        return AVERROR(ENOMEM);

    ret = av_parse_video_rate(&st->avg_frame_rate, c->framerate);
    if (ret < 0)
        return ret;

    avpriv_set_pts_info(st, 64, 1, 1000000);

    gc  = xcb_get_geometry(c->conn, c->screen->root);
    geo = xcb_get_geometry_reply(c->conn, gc, NULL);
    if (!geo)
        return AVERROR_EXTERNAL;

    if (!c->width || !c->height) {
        c->width = geo->width;
        c->height = geo->height;
    }

    if (c->x + c->width > geo->width ||
        c->y + c->height > geo->height) {
        av_log(s, AV_LOG_ERROR,
               "Capture area %dx%d at position %d.%d "
               "outside the screen size %dx%d\n",
               c->width, c->height,
               c->x, c->y,
               geo->width, geo->height);
        free(geo);
        return AVERROR(EINVAL);
    }

    c->time_base  = (AVRational){ st->avg_frame_rate.den,
                                  st->avg_frame_rate.num };
    c->frame_duration = av_rescale_q(1, c->time_base, AV_TIME_BASE_Q);
    c->time_frame = av_gettime();

    ret = pixfmt_from_pixmap_format(s, geo->depth, &st->codecpar->format, &c->bpp);
    free(geo);
    if (ret < 0)
        return ret;

    frame_size_bits = (int64_t)c->width * c->height * c->bpp;
    if (frame_size_bits / 8 + AV_INPUT_BUFFER_PADDING_SIZE > INT_MAX) {
        av_log(s, AV_LOG_ERROR, "Captured area is too large\n");
        return AVERROR_PATCHWELCOME;
    }
    c->frame_size = frame_size_bits / 8;

#if CONFIG_LIBXCB_SHM
    c->shm_pool = av_buffer_pool_init2(c->frame_size + AV_INPUT_BUFFER_PADDING_SIZE,
                                           c->conn, allocate_shm_buffer, NULL);
    if (!c->shm_pool)
        return AVERROR(ENOMEM);
#endif

    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
    st->codecpar->codec_id   = AV_CODEC_ID_RAWVIDEO;
    st->codecpar->width      = c->width;
    st->codecpar->height     = c->height;
    st->codecpar->bit_rate   = av_rescale(frame_size_bits, st->avg_frame_rate.num, st->avg_frame_rate.den);

    return ret;
}

static void draw_rectangle(AVFormatContext *s)
{
    XCBGrabContext *c = s->priv_data;
    xcb_gcontext_t gc = xcb_generate_id(c->conn);
    uint32_t mask     = XCB_GC_FOREGROUND |
                        XCB_GC_BACKGROUND |
                        XCB_GC_LINE_WIDTH |
                        XCB_GC_LINE_STYLE |
                        XCB_GC_FILL_STYLE;
    uint32_t values[] = { c->screen->black_pixel,
                          c->screen->white_pixel,
                          c->region_border,
                          XCB_LINE_STYLE_DOUBLE_DASH,
                          XCB_FILL_STYLE_SOLID };
    xcb_rectangle_t r = { 1, 1,
                          c->width  + c->region_border * 2 - 3,
                          c->height + c->region_border * 2 - 3 };

    xcb_create_gc(c->conn, gc, c->window, mask, values);

    xcb_poly_rectangle(c->conn, c->window, gc, 1, &r);
}

static void setup_window(AVFormatContext *s)
{
    XCBGrabContext *c = s->priv_data;
    uint32_t mask     = XCB_CW_OVERRIDE_REDIRECT | XCB_CW_EVENT_MASK;
    uint32_t values[] = { 1,
                          XCB_EVENT_MASK_EXPOSURE |
                          XCB_EVENT_MASK_STRUCTURE_NOTIFY };
    av_unused xcb_rectangle_t rect = { 0, 0, c->width, c->height };

    c->window = xcb_generate_id(c->conn);

    xcb_create_window(c->conn, XCB_COPY_FROM_PARENT,
                      c->window,
                      c->screen->root,
                      c->x - c->region_border,
                      c->y - c->region_border,
                      c->width + c->region_border * 2,
                      c->height + c->region_border * 2,
                      0,
                      XCB_WINDOW_CLASS_INPUT_OUTPUT,
                      XCB_COPY_FROM_PARENT,
                      mask, values);

#if CONFIG_LIBXCB_SHAPE
    xcb_shape_rectangles(c->conn, XCB_SHAPE_SO_SUBTRACT,
                         XCB_SHAPE_SK_BOUNDING, XCB_CLIP_ORDERING_UNSORTED,
                         c->window,
                         c->region_border, c->region_border,
                         1, &rect);
#endif

    xcb_map_window(c->conn, c->window);

    draw_rectangle(s);
}

static av_cold int xcbgrab_read_header(AVFormatContext *s)
{
    XCBGrabContext *c = s->priv_data;
    int screen_num, ret;
    const xcb_setup_t *setup;
    char *display_name = av_strdup(s->url);

    if (!display_name)
        return AVERROR(ENOMEM);

    if (!sscanf(s->url, "%[^+]+%d,%d", display_name, &c->x, &c->y)) {
        *display_name = 0;
        sscanf(s->url, "+%d,%d", &c->x, &c->y);
    }

    c->conn = xcb_connect(display_name[0] ? display_name : NULL, &screen_num);
    av_freep(&display_name);

    if ((ret = xcb_connection_has_error(c->conn))) {
        av_log(s, AV_LOG_ERROR, "Cannot open display %s, error %d.\n",
               s->url[0] ? s->url : "default", ret);
        return AVERROR(EIO);
    }

    setup = xcb_get_setup(c->conn);

    c->screen = get_screen(setup, screen_num);
    if (!c->screen) {
        av_log(s, AV_LOG_ERROR, "The screen %d does not exist.\n",
               screen_num);
        xcbgrab_read_close(s);
        return AVERROR(EIO);
    }

    ret = create_stream(s);

    if (ret < 0) {
        xcbgrab_read_close(s);
        return ret;
    }

#if CONFIG_LIBXCB_SHM
    c->has_shm = check_shm(c->conn);
#endif

#if CONFIG_LIBXCB_XFIXES
    if (c->draw_mouse) {
        if (!(c->draw_mouse = check_xfixes(c->conn))) {
            av_log(s, AV_LOG_WARNING,
                   "XFixes not available, cannot draw the mouse.\n");
        }
        if (c->bpp < 24) {
            avpriv_report_missing_feature(s, "%d bits per pixel screen",
                                          c->bpp);
            c->draw_mouse = 0;
        }
    }
#endif

    if (c->show_region)
        setup_window(s);

    return 0;
}

AVInputFormat ff_xcbgrab_demuxer = {
    .name           = "x11grab",
    .long_name      = NULL_IF_CONFIG_SMALL("X11 screen capture, using XCB"),
    .priv_data_size = sizeof(XCBGrabContext),
    .read_header    = xcbgrab_read_header,
    .read_packet    = xcbgrab_read_packet,
    .read_close     = xcbgrab_read_close,
    .flags          = AVFMT_NOFILE,
    .priv_class     = &xcbgrab_class,
};


Generated by: GCOVR (Version 4.2)

Line	Branch	Exec	Source
1			/*
2			* XCB input grabber
3			* Copyright (C) 2014 Luca Barbato <lu_zero@gentoo.org>
4			*
5			* This file is part of FFmpeg.
6			*
7			* FFmpeg is free software; you can redistribute it and/or
8			* modify it under the terms of the GNU Lesser General Public
9			* License as published by the Free Software Foundation; either
10			* version 2.1 of the License, or (at your option) any later version.
11			*
12			* FFmpeg is distributed in the hope that it will be useful,
13			* but WITHOUT ANY WARRANTY; without even the implied warranty of
14			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15			* Lesser General Public License for more details.
16			*
17			* You should have received a copy of the GNU Lesser General Public
18			* License along with FFmpeg; if not, write to the Free Software
19			* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20			*/
21
22			#include "config.h"
23
24			#include <stdlib.h>
25			#include <xcb/xcb.h>
26
27			#if CONFIG_LIBXCB_XFIXES
28			#include <xcb/xfixes.h>
29			#endif
30
31			#if CONFIG_LIBXCB_SHM
32			#include <sys/shm.h>
33			#include <xcb/shm.h>
34			#endif
35
36			#if CONFIG_LIBXCB_SHAPE
37			#include <xcb/shape.h>
38			#endif
39
40			#include "libavutil/internal.h"
41			#include "libavutil/mathematics.h"
42			#include "libavutil/opt.h"
43			#include "libavutil/parseutils.h"
44			#include "libavutil/time.h"
45
46			#include "libavformat/avformat.h"
47			#include "libavformat/internal.h"
48
49			typedef struct XCBGrabContext {
50			const AVClass *class;
51
52			xcb_connection_t *conn;
53			xcb_screen_t *screen;
54			xcb_window_t window;
55			#if CONFIG_LIBXCB_SHM
56			AVBufferPool *shm_pool;
57			#endif
58			int64_t time_frame;
59			AVRational time_base;
60			int64_t frame_duration;
61
62			int x, y;
63			int width, height;
64			int frame_size;
65			int bpp;
66
67			int draw_mouse;
68			int follow_mouse;
69			int show_region;
70			int region_border;
71			int centered;
72
73			const char *framerate;
74
75			int has_shm;
76			} XCBGrabContext;
77
78			#define FOLLOW_CENTER -1
79
80			#define OFFSET(x) offsetof(XCBGrabContext, x)
81			#define D AV_OPT_FLAG_DECODING_PARAM
82			static const AVOption options[] = {
83			{ "x", "Initial x coordinate.", OFFSET(x), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
84			{ "y", "Initial y coordinate.", OFFSET(y), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
85			{ "grab_x", "Initial x coordinate.", OFFSET(x), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
86			{ "grab_y", "Initial y coordinate.", OFFSET(y), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, D },
87			{ "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL }, 0, 0, D },
88			{ "framerate", "", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "ntsc" }, 0, 0, D },
89			{ "draw_mouse", "Draw the mouse pointer.", OFFSET(draw_mouse), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, D },
90			{ "follow_mouse", "Move the grabbing region when the mouse pointer reaches within specified amount of pixels to the edge of region.",
91			OFFSET(follow_mouse), AV_OPT_TYPE_INT, { .i64 = 0 }, FOLLOW_CENTER, INT_MAX, D, "follow_mouse" },
92			{ "centered", "Keep the mouse pointer at the center of grabbing region when following.", 0, AV_OPT_TYPE_CONST, { .i64 = -1 }, INT_MIN, INT_MAX, D, "follow_mouse" },
93			{ "show_region", "Show the grabbing region.", OFFSET(show_region), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, D },
94			{ "region_border", "Set the region border thickness.", OFFSET(region_border), AV_OPT_TYPE_INT, { .i64 = 3 }, 1, 128, D },
95			{ NULL },
96			};
97
98			static const AVClass xcbgrab_class = {
99			.class_name = "xcbgrab indev",
100			.item_name = av_default_item_name,
101			.option = options,
102			.version = LIBAVUTIL_VERSION_INT,
103			.category = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
104			};
105
106			static int xcbgrab_reposition(AVFormatContext *s,
107			xcb_query_pointer_reply_t *p,
108			xcb_get_geometry_reply_t *geo)
109			{
110			XCBGrabContext *c = s->priv_data;
111			int x = c->x, y = c->y;
112			int w = c->width, h = c->height, f = c->follow_mouse;
113			int p_x, p_y;
114
115			if (!p \|\| !geo)
116			return AVERROR(EIO);
117
118			p_x = p->win_x;
119			p_y = p->win_y;
120
121			if (f == FOLLOW_CENTER) {
122			x = p_x - w / 2;
123			y = p_y - h / 2;
124			} else {
125			int left = x + f;
126			int right = x + w - f;
127			int top = y + f;
128			int bottom = y + h - f;
129			if (p_x > right) {
130			x += p_x - right;
131			} else if (p_x < left) {
132			x -= left - p_x;
133			}
134			if (p_y > bottom) {
135			y += p_y - bottom;
136			} else if (p_y < top) {
137			y -= top - p_y;
138			}
139			}
140
141			c->x = FFMIN(FFMAX(0, x), geo->width - w);
142			c->y = FFMIN(FFMAX(0, y), geo->height - h);
143
144			return 0;
145			}
146
147			static void xcbgrab_image_reply_free(void opaque, uint8_t data)
148			{
149			free(opaque);
150			}
151
152			static int xcbgrab_frame(AVFormatContext s, AVPacket pkt)
153			{
154			XCBGrabContext *c = s->priv_data;
155			xcb_get_image_cookie_t iq;
156			xcb_get_image_reply_t *img;
157			xcb_drawable_t drawable = c->screen->root;
158			xcb_generic_error_t *e = NULL;
159			uint8_t *data;
160			int length;
161
162			iq = xcb_get_image(c->conn, XCB_IMAGE_FORMAT_Z_PIXMAP, drawable,
163			c->x, c->y, c->width, c->height, ~0);
164
165			img = xcb_get_image_reply(c->conn, iq, &e);
166
167			if (e) {
168			av_log(s, AV_LOG_ERROR,
169			"Cannot get the image data "
170			"event_error: response_type:%u error_code:%u "
171			"sequence:%u resource_id:%u minor_code:%u major_code:%u.\n",
172			e->response_type, e->error_code,
173			e->sequence, e->resource_id, e->minor_code, e->major_code);
174			free(e);
175			return AVERROR(EACCES);
176			}
177
178			if (!img)
179			return AVERROR(EAGAIN);
180
181			data = xcb_get_image_data(img);
182			length = xcb_get_image_data_length(img);
183
184			av_init_packet(pkt);
185
186			pkt->buf = av_buffer_create(data, length, xcbgrab_image_reply_free, img, 0);
187			if (!pkt->buf) {
188			free(img);
189			return AVERROR(ENOMEM);
190			}
191
192			pkt->data = data;
193			pkt->size = length;
194
195			return 0;
196			}
197
198			static int64_t wait_frame(AVFormatContext s, AVPacket pkt)
199			{
200			XCBGrabContext *c = s->priv_data;
201			int64_t curtime, delay;
202
203			c->time_frame += c->frame_duration;
204
205			for (;;) {
206			curtime = av_gettime();
207			delay = c->time_frame - curtime;
208			if (delay <= 0)
209			break;
210			av_usleep(delay);
211			}
212
213			return curtime;
214			}
215
216			#if CONFIG_LIBXCB_SHM
217			static int check_shm(xcb_connection_t *conn)
218			{
219			xcb_shm_query_version_cookie_t cookie = xcb_shm_query_version(conn);
220			xcb_shm_query_version_reply_t *reply;
221
222			reply = xcb_shm_query_version_reply(conn, cookie, NULL);
223			if (reply) {
224			free(reply);
225			return 1;
226			}
227
228			return 0;
229			}
230
231			static void free_shm_buffer(void opaque, uint8_t data)
232			{
233			shmdt(data);
234			}
235
236			static AVBufferRef allocate_shm_buffer(void opaque, int size)
237			{
238			xcb_connection_t *conn = opaque;
239			xcb_shm_seg_t segment;
240			AVBufferRef *ref;
241			uint8_t *data;
242			int id;
243
244			id = shmget(IPC_PRIVATE, size, IPC_CREAT \| 0777);
245			if (id == -1)
246			return NULL;
247
248			segment = xcb_generate_id(conn);
249			xcb_shm_attach(conn, segment, id, 0);
250			data = shmat(id, NULL, 0);
251			shmctl(id, IPC_RMID, 0);
252			if ((intptr_t)data == -1 \|\| !data)
253			return NULL;
254
255			ref = av_buffer_create(data, size, free_shm_buffer, (void *)(ptrdiff_t)segment, 0);
256			if (!ref)
257			shmdt(data);
258
259			return ref;
260			}
261
262			static int xcbgrab_frame_shm(AVFormatContext s, AVPacket pkt)
263			{
264			XCBGrabContext *c = s->priv_data;
265			xcb_shm_get_image_cookie_t iq;
266			xcb_shm_get_image_reply_t *img;
267			xcb_drawable_t drawable = c->screen->root;
268			xcb_generic_error_t *e = NULL;
269			AVBufferRef *buf;
270			xcb_shm_seg_t segment;
271
272			buf = av_buffer_pool_get(c->shm_pool);
273			if (!buf) {
274			av_log(s, AV_LOG_ERROR, "Could not get shared memory buffer.\n");
275			return AVERROR(ENOMEM);
276			}
277			segment = (xcb_shm_seg_t)av_buffer_pool_buffer_get_opaque(buf);
278
279			iq = xcb_shm_get_image(c->conn, drawable,
280			c->x, c->y, c->width, c->height, ~0,
281			XCB_IMAGE_FORMAT_Z_PIXMAP, segment, 0);
282			img = xcb_shm_get_image_reply(c->conn, iq, &e);
283
284			xcb_flush(c->conn);
285
286			if (e) {
287			av_log(s, AV_LOG_ERROR,
288			"Cannot get the image data "
289			"event_error: response_type:%u error_code:%u "
290			"sequence:%u resource_id:%u minor_code:%u major_code:%u.\n",
291			e->response_type, e->error_code,
292			e->sequence, e->resource_id, e->minor_code, e->major_code);
293
294			free(e);
295			av_buffer_unref(&buf);
296			return AVERROR(EACCES);
297			}
298
299			free(img);
300
301			av_init_packet(pkt);
302
303			pkt->buf = buf;
304			pkt->data = buf->data;
305			pkt->size = c->frame_size;
306
307			return 0;
308			}
309			#endif /* CONFIG_LIBXCB_SHM */
310
311			#if CONFIG_LIBXCB_XFIXES
312			static int check_xfixes(xcb_connection_t *conn)
313			{
314			xcb_xfixes_query_version_cookie_t cookie;
315			xcb_xfixes_query_version_reply_t *reply;
316
317			cookie = xcb_xfixes_query_version(conn, XCB_XFIXES_MAJOR_VERSION,
318			XCB_XFIXES_MINOR_VERSION);
319			reply = xcb_xfixes_query_version_reply(conn, cookie, NULL);
320
321			if (reply) {
322			free(reply);
323			return 1;
324			}
325			return 0;
326			}
327
328			#define BLEND(target, source, alpha) \
329			(target) + ((source) * (255 - (alpha)) + 255 / 2) / 255
330
331			static void xcbgrab_draw_mouse(AVFormatContext s, AVPacket pkt,
332			xcb_query_pointer_reply_t *p,
333			xcb_get_geometry_reply_t *geo)
334			{
335			XCBGrabContext *gr = s->priv_data;
336			uint32_t *cursor;
337			uint8_t *image = pkt->data;
338			int stride = gr->bpp / 8;
339			xcb_xfixes_get_cursor_image_cookie_t cc;
340			xcb_xfixes_get_cursor_image_reply_t *ci;
341			int cx, cy, x, y, w, h, c_off, i_off;
342
343			cc = xcb_xfixes_get_cursor_image(gr->conn);
344			ci = xcb_xfixes_get_cursor_image_reply(gr->conn, cc, NULL);
345			if (!ci)
346			return;
347
348			cursor = xcb_xfixes_get_cursor_image_cursor_image(ci);
349			if (!cursor)
350			return;
351
352			cx = ci->x - ci->xhot;
353			cy = ci->y - ci->yhot;
354
355			x = FFMAX(cx, gr->x);
356			y = FFMAX(cy, gr->y);
357
358			w = FFMIN(cx + ci->width, gr->x + gr->width) - x;
359			h = FFMIN(cy + ci->height, gr->y + gr->height) - y;
360
361			c_off = x - cx;
362			i_off = x - gr->x;
363
364			cursor += (y - cy) * ci->width;
365			image += (y - gr->y) * gr->width * stride;
366
367			for (y = 0; y < h; y++) {
368			cursor += c_off;
369			image += i_off * stride;
370			for (x = 0; x < w; x++, cursor++, image += stride) {
371			int r, g, b, a;
372
373			r = *cursor & 0xff;
374			g = (*cursor >> 8) & 0xff;
375			b = (*cursor >> 16) & 0xff;
376			a = (*cursor >> 24) & 0xff;
377
378			if (!a)
379			continue;
380
381			if (a == 255) {
382			image[0] = r;
383			image[1] = g;
384			image[2] = b;
385			} else {
386			image[0] = BLEND(r, image[0], a);
387			image[1] = BLEND(g, image[1], a);
388			image[2] = BLEND(b, image[2], a);
389			}
390
391			}
392			cursor += ci->width - w - c_off;
393			image += (gr->width - w - i_off) * stride;
394			}
395
396			free(ci);
397			}
398			#endif /* CONFIG_LIBXCB_XFIXES */
399
400			static void xcbgrab_update_region(AVFormatContext *s)
401			{
402			XCBGrabContext *c = s->priv_data;
403			const uint32_t args[] = { c->x - c->region_border,
404			c->y - c->region_border };
405
406			xcb_configure_window(c->conn,
407			c->window,
408			XCB_CONFIG_WINDOW_X \| XCB_CONFIG_WINDOW_Y,
409			args);
410			}
411
412			static int xcbgrab_read_packet(AVFormatContext s, AVPacket pkt)
413			{
414			XCBGrabContext *c = s->priv_data;
415			xcb_query_pointer_cookie_t pc;
416			xcb_get_geometry_cookie_t gc;
417			xcb_query_pointer_reply_t *p = NULL;
418			xcb_get_geometry_reply_t *geo = NULL;
419			int ret = 0;
420			int64_t pts;
421
422			pts = wait_frame(s, pkt);
423
424			if (c->follow_mouse \|\| c->draw_mouse) {
425			pc = xcb_query_pointer(c->conn, c->screen->root);
426			gc = xcb_get_geometry(c->conn, c->screen->root);
427			p = xcb_query_pointer_reply(c->conn, pc, NULL);
428			geo = xcb_get_geometry_reply(c->conn, gc, NULL);
429			}
430
431			if (c->follow_mouse && p->same_screen)
432			xcbgrab_reposition(s, p, geo);
433
434			if (c->show_region)
435			xcbgrab_update_region(s);
436
437			#if CONFIG_LIBXCB_SHM
438			if (c->has_shm && xcbgrab_frame_shm(s, pkt) < 0) {
439			av_log(s, AV_LOG_WARNING, "Continuing without shared memory.\n");
440			c->has_shm = 0;
441			}
442			#endif
443			if (!c->has_shm)
444			ret = xcbgrab_frame(s, pkt);
445			pkt->dts = pkt->pts = pts;
446			pkt->duration = c->frame_duration;
447
448			#if CONFIG_LIBXCB_XFIXES
449			if (ret >= 0 && c->draw_mouse && p->same_screen)
450			xcbgrab_draw_mouse(s, pkt, p, geo);
451			#endif
452
453			free(p);
454			free(geo);
455
456			return ret;
457			}
458
459			static av_cold int xcbgrab_read_close(AVFormatContext *s)
460			{
461			XCBGrabContext *ctx = s->priv_data;
462
463			#if CONFIG_LIBXCB_SHM
464			av_buffer_pool_uninit(&ctx->shm_pool);
465			#endif
466
467			xcb_disconnect(ctx->conn);
468
469			return 0;
470			}
471
472			static xcb_screen_t get_screen(const xcb_setup_t setup, int screen_num)
473			{
474			xcb_screen_iterator_t it = xcb_setup_roots_iterator(setup);
475			xcb_screen_t *screen = NULL;
476
477			for (; it.rem > 0; xcb_screen_next (&it)) {
478			if (!screen_num) {
479			screen = it.data;
480			break;
481			}
482
483			screen_num--;
484			}
485
486			return screen;
487			}
488
489			static int pixfmt_from_pixmap_format(AVFormatContext *s, int depth,
490			int pix_fmt, int bpp)
491			{
492			XCBGrabContext *c = s->priv_data;
493			const xcb_setup_t *setup = xcb_get_setup(c->conn);
494			const xcb_format_t *fmt = xcb_setup_pixmap_formats(setup);
495			int length = xcb_setup_pixmap_formats_length(setup);
496
497			*pix_fmt = 0;
498
499			while (length--) {
500			if (fmt->depth == depth) {
501			switch (depth) {
502			case 32:
503			if (fmt->bits_per_pixel == 32)
504			*pix_fmt = AV_PIX_FMT_0RGB;
505			break;
506			case 24:
507			if (fmt->bits_per_pixel == 32)
508			*pix_fmt = AV_PIX_FMT_0RGB32;
509			else if (fmt->bits_per_pixel == 24)
510			*pix_fmt = AV_PIX_FMT_RGB24;
511			break;
512			case 16:
513			if (fmt->bits_per_pixel == 16)
514			*pix_fmt = AV_PIX_FMT_RGB565;
515			break;
516			case 15:
517			if (fmt->bits_per_pixel == 16)
518			*pix_fmt = AV_PIX_FMT_RGB555;
519			break;
520			case 8:
521			if (fmt->bits_per_pixel == 8)
522			*pix_fmt = AV_PIX_FMT_RGB8;
523			break;
524			}
525			}
526
527			if (*pix_fmt) {
528			*bpp = fmt->bits_per_pixel;
529			return 0;
530			}
531
532			fmt++;
533			}
534			avpriv_report_missing_feature(s, "Mapping this pixmap format");
535
536			return AVERROR_PATCHWELCOME;
537			}
538
539			static int create_stream(AVFormatContext *s)
540			{
541			XCBGrabContext *c = s->priv_data;
542			AVStream *st = avformat_new_stream(s, NULL);
543			xcb_get_geometry_cookie_t gc;
544			xcb_get_geometry_reply_t *geo;
545			int64_t frame_size_bits;
546			int ret;
547
548			if (!st)
549			return AVERROR(ENOMEM);
550
551			ret = av_parse_video_rate(&st->avg_frame_rate, c->framerate);
552			if (ret < 0)
553			return ret;
554
555			avpriv_set_pts_info(st, 64, 1, 1000000);
556
557			gc = xcb_get_geometry(c->conn, c->screen->root);
558			geo = xcb_get_geometry_reply(c->conn, gc, NULL);
559			if (!geo)
560			return AVERROR_EXTERNAL;
561
562			if (!c->width \|\| !c->height) {
563			c->width = geo->width;
564			c->height = geo->height;
565			}
566
567			if (c->x + c->width > geo->width \|\|
568			c->y + c->height > geo->height) {
569			av_log(s, AV_LOG_ERROR,
570			"Capture area %dx%d at position %d.%d "
571			"outside the screen size %dx%d\n",
572			c->width, c->height,
573			c->x, c->y,
574			geo->width, geo->height);
575			free(geo);
576			return AVERROR(EINVAL);
577			}
578
579			c->time_base = (AVRational){ st->avg_frame_rate.den,
580			st->avg_frame_rate.num };
581			c->frame_duration = av_rescale_q(1, c->time_base, AV_TIME_BASE_Q);
582			c->time_frame = av_gettime();
583
584			ret = pixfmt_from_pixmap_format(s, geo->depth, &st->codecpar->format, &c->bpp);
585			free(geo);
586			if (ret < 0)
587			return ret;
588
589			frame_size_bits = (int64_t)c->width * c->height * c->bpp;
590			if (frame_size_bits / 8 + AV_INPUT_BUFFER_PADDING_SIZE > INT_MAX) {
591			av_log(s, AV_LOG_ERROR, "Captured area is too large\n");
592			return AVERROR_PATCHWELCOME;
593			}
594			c->frame_size = frame_size_bits / 8;
595
596			#if CONFIG_LIBXCB_SHM
597			c->shm_pool = av_buffer_pool_init2(c->frame_size + AV_INPUT_BUFFER_PADDING_SIZE,
598			c->conn, allocate_shm_buffer, NULL);
599			if (!c->shm_pool)
600			return AVERROR(ENOMEM);
601			#endif
602
603			st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
604			st->codecpar->codec_id = AV_CODEC_ID_RAWVIDEO;
605			st->codecpar->width = c->width;
606			st->codecpar->height = c->height;
607			st->codecpar->bit_rate = av_rescale(frame_size_bits, st->avg_frame_rate.num, st->avg_frame_rate.den);
608
609			return ret;
610			}
611
612			static void draw_rectangle(AVFormatContext *s)
613			{
614			XCBGrabContext *c = s->priv_data;
615			xcb_gcontext_t gc = xcb_generate_id(c->conn);
616			uint32_t mask = XCB_GC_FOREGROUND \|
617			XCB_GC_BACKGROUND \|
618			XCB_GC_LINE_WIDTH \|
619			XCB_GC_LINE_STYLE \|
620			XCB_GC_FILL_STYLE;
621			uint32_t values[] = { c->screen->black_pixel,
622			c->screen->white_pixel,
623			c->region_border,
624			XCB_LINE_STYLE_DOUBLE_DASH,
625			XCB_FILL_STYLE_SOLID };
626			xcb_rectangle_t r = { 1, 1,
627			c->width + c->region_border * 2 - 3,
628			c->height + c->region_border * 2 - 3 };
629
630			xcb_create_gc(c->conn, gc, c->window, mask, values);
631
632			xcb_poly_rectangle(c->conn, c->window, gc, 1, &r);
633			}
634
635			static void setup_window(AVFormatContext *s)
636			{
637			XCBGrabContext *c = s->priv_data;
638			uint32_t mask = XCB_CW_OVERRIDE_REDIRECT \| XCB_CW_EVENT_MASK;
639			uint32_t values[] = { 1,
640			XCB_EVENT_MASK_EXPOSURE \|
641			XCB_EVENT_MASK_STRUCTURE_NOTIFY };
642			av_unused xcb_rectangle_t rect = { 0, 0, c->width, c->height };
643
644			c->window = xcb_generate_id(c->conn);
645
646			xcb_create_window(c->conn, XCB_COPY_FROM_PARENT,
647			c->window,
648			c->screen->root,
649			c->x - c->region_border,
650			c->y - c->region_border,
651			c->width + c->region_border * 2,
652			c->height + c->region_border * 2,
653			0,
654			XCB_WINDOW_CLASS_INPUT_OUTPUT,
655			XCB_COPY_FROM_PARENT,
656			mask, values);
657
658			#if CONFIG_LIBXCB_SHAPE
659			xcb_shape_rectangles(c->conn, XCB_SHAPE_SO_SUBTRACT,
660			XCB_SHAPE_SK_BOUNDING, XCB_CLIP_ORDERING_UNSORTED,
661			c->window,
662			c->region_border, c->region_border,
663			1, &rect);
664			#endif
665
666			xcb_map_window(c->conn, c->window);
667
668			draw_rectangle(s);
669			}
670
671			static av_cold int xcbgrab_read_header(AVFormatContext *s)
672			{
673			XCBGrabContext *c = s->priv_data;
674			int screen_num, ret;
675			const xcb_setup_t *setup;
676			char *display_name = av_strdup(s->url);
677
678			if (!display_name)
679			return AVERROR(ENOMEM);
680
681			if (!sscanf(s->url, "%[^+]+%d,%d", display_name, &c->x, &c->y)) {
682			*display_name = 0;
683			sscanf(s->url, "+%d,%d", &c->x, &c->y);
684			}
685
686			c->conn = xcb_connect(display_name[0] ? display_name : NULL, &screen_num);
687			av_freep(&display_name);
688
689			if ((ret = xcb_connection_has_error(c->conn))) {
690			av_log(s, AV_LOG_ERROR, "Cannot open display %s, error %d.\n",
691			s->url[0] ? s->url : "default", ret);
692			return AVERROR(EIO);
693			}
694
695			setup = xcb_get_setup(c->conn);
696
697			c->screen = get_screen(setup, screen_num);
698			if (!c->screen) {
699			av_log(s, AV_LOG_ERROR, "The screen %d does not exist.\n",
700			screen_num);
701			xcbgrab_read_close(s);
702			return AVERROR(EIO);
703			}
704
705			ret = create_stream(s);
706
707			if (ret < 0) {
708			xcbgrab_read_close(s);
709			return ret;
710			}
711
712			#if CONFIG_LIBXCB_SHM
713			c->has_shm = check_shm(c->conn);
714			#endif
715
716			#if CONFIG_LIBXCB_XFIXES
717			if (c->draw_mouse) {
718			if (!(c->draw_mouse = check_xfixes(c->conn))) {
719			av_log(s, AV_LOG_WARNING,
720			"XFixes not available, cannot draw the mouse.\n");
721			}
722			if (c->bpp < 24) {
723			avpriv_report_missing_feature(s, "%d bits per pixel screen",
724			c->bpp);
725			c->draw_mouse = 0;
726			}
727			}
728			#endif
729
730			if (c->show_region)
731			setup_window(s);
732
733			return 0;
734			}
735
736			AVInputFormat ff_xcbgrab_demuxer = {
737			.name = "x11grab",
738			.long_name = NULL_IF_CONFIG_SMALL("X11 screen capture, using XCB"),
739			.priv_data_size = sizeof(XCBGrabContext),
740			.read_header = xcbgrab_read_header,
741			.read_packet = xcbgrab_read_packet,
742			.read_close = xcbgrab_read_close,
743			.flags = AVFMT_NOFILE,
744			.priv_class = &xcbgrab_class,
745			};