Ubuntu24 主机源码编译qt6.5

问题一：-xcb作为后端问题记录

在源码外目录新建hostbuild作为编译输出目录，在hostbuild新建build.sh编译脚本，记得用

chmod +x build.sh

添加运行权限

#/bin/bash
../qt-everywhere-src-6.5.4/configure -extprefix /home/li/workplace/local \
-shared \
-platform linux-g++ \
-xcb \
-Wno-dev \
-redo

Feature "xcb": Forcing to "ON" breaks its condition:

      QT_FEATURE_thread AND TARGET XCB::XCB AND TEST_xcb_syslibs AND QT_FEATURE_xkbcommon_x11

  Condition values dump:

      QT_FEATURE_thread = "ON"
      TARGET XCB::XCB found
      TEST_xcb_syslibs = "FALSE"
      QT_FEATURE_xkbcommon_x11 not evaluated

出错在TEST_xcb_syslibs = "FALSE"条件不成立；测试条件可以在源码中找到，源码路径qt-everywhere-src-6.5.4/qtbase/src/gui/configure.cmake
截取部分代码。意思可以看出所需的库XCB::CURSOR~XCB::XCB都要有，才成立了。

# xcb_syslibs
qt_config_compile_test(xcb_syslibs
    LABEL "XCB (extensions)"
    LIBRARIES
        XCB::CURSOR
        XCB::ICCCM
        XCB::IMAGE
        XCB::KEYSYMS
        XCB::RANDR
        XCB::RENDER
        XCB::RENDERUTIL
        XCB::SHAPE
        XCB::SHM
        XCB::SYNC
        XCB::XFIXES
        XCB::XKB
        XCB::XCB
    CODE
"// xkb.h is using a variable called 'explicit', which is a reserved keyword in C++
#define explicit dont_use_cxx_explicit
#include <xcb/xcb.h>
#include <xcb/xcb_image.h>
#include <xcb/xcb_keysyms.h>
#include <xcb/xcb_cursor.h>
#include <xcb/randr.h>
#include <xcb/render.h>
#include <xcb/shape.h>
#include <xcb/shm.h>
#include <xcb/sync.h>
#include <xcb/xfixes.h>
#include <xcb/xcb_icccm.h>
#include <xcb/xcb_renderutil.h>
#include <xcb/xkb.h>
#undef explicit

int main(void)
{
    /* BEGIN TEST: */
int primaryScreen = 0;
xcb_connection_t *c = xcb_connect(\"\", &primaryScreen);
/* RENDER */
xcb_generic_error_t *error = nullptr;
xcb_render_query_pict_formats_cookie_t formatsCookie =
    xcb_render_query_pict_formats(c);
xcb_render_query_pict_formats_reply_t *formatsReply =
    xcb_render_query_pict_formats_reply(c, formatsCookie, &error);
/* RENDERUTIL: xcb_renderutil.h include won't compile unless version >= 0.3.9 */
xcb_render_util_find_standard_format(nullptr, XCB_PICT_STANDARD_ARGB_32);
/* XKB: This takes more arguments in xcb-xkb < 1.11 */
xcb_xkb_get_kbd_by_name_replies_key_names_value_list_sizeof(nullptr, 0, 0, 0, 0, 0, 0, 0, 0);
    /* END TEST: */
    return 0;
}
")

解决方法：

sudo apt-get install \
    libxcb-cursor-dev \
    libxcb-icccm4-dev \
    libxcb-image0-dev \
    libxcb-keysyms1-dev \
    libxcb-randr0-dev \
    libxcb-render0-dev \
    libxcb-render-util0-dev \
    libxcb-shape0-dev \
    libxcb-shm0-dev \
    libxcb-sync-dev \
    libxcb-xfixes0-dev \
    libxcb-xkb-dev \
    libxcb1-dev

Multimedia 模块使用ffmpeg作为后端

link
前提已经编译好ffmpeg二进制文件，<FFMPEG_DIR>路径为make install到的文件夹，里面包含bin、include、lib文件；建议使用静态库。
注意点:
在Linux环境，要安装pulseaudio开发环境,不然发现不了ffmpeg,使用-pulseaudio,就不要使用-alsa,经测会有冲突

sudo apt install libpulse-dev

示例

configure -- -DFFMPEG_DIR=<FFMPEG_DIR>

实例

../qt-everywhere-src-6.5.4/configure \
-prefix /home/li/workplace/local/hostqt6.5.4 \
-pulseaudio \
-- -DFFMPEG_DIR=/home/li/workplace/local/hostffmpeg4

正确的config.summary截取如下片段

Qt Multimedia:
  Spatial Audio .......................... yes
  Spatial Audio (Quick3D) ................ yes
  Low level Audio Backend:
    ALSA (experimental) .................. no
    PulseAudio ........................... yes
    MMRenderer ........................... no
    CoreAudio ............................ no
    Windows Media SDK .................... no
    Open SLES (Android) .................. no
    Web Assembly ......................... no
  Plugin:
    GStreamer 1.0 ........................ no
    FFmpeg ............................... yes
    MMRenderer ........................... no
    AVFoundation ......................... no
    Windows Media Foundation ............. no
  Hardware acceleration and features:
    Video for Linux ...................... yes
    VAAPI support ........................ no
    Linux DMA buffer support ............. yes
    VideoToolbox ......................... no
Qt 3D: