Qt 使用gstreamer API播放音频文件时出现问题：应用程序挂起 我用C++编写了一个简单的音频播放器应用程序。我跟着。这是我的代码： CMediaPlayer::CMediaPlayer(QString path) { gst_init(NULL, NULL); createElements(path); } createElements(QString &path) { /* Create gstreamer elements */ m_pipeline = gst_pipeline_new("audio-player"); m_fileSource = gst_element_factory_make("filesrc", "file-source"); m_audioDecoder = gst_element_factory_make("mad", "mp3-decoder"); m_volume = gst_element_factory_make("volume", "volume-name"); m_audioConverter = gst_element_factory_make("audioconvert", "audio-converter"); m_sink = gst_element_factory_make("alsasink", "audio-output"); if (!m_pipeline || !m_fileSource || !m_audioDecoder || !m_volume || !m_audioConverter || !m_sink) { g_printerr ("One or more elements could not be created !! \n"); return false; } /* Set up the pipeline */ else { /* set a message handler on a bus */ GstBus *bus = gst_pipeline_get_bus (GST_PIPELINE (m_pipeline)); gst_bus_add_watch(bus, bus_call, m_loop); gst_object_unref(bus); g_object_set (G_OBJECT (m_fileSource), "location", path.toLatin1().data(), NULL); /* add all elements into the pipeline */ gst_bin_add_many (GST_BIN (m_pipeline), m_fileSource, m_audioDecoder, m_volume, m_audioConverter, m_sink, NULL); /* link the elements together */ if(!gst_element_link_many (m_fileSource, m_audioDecoder, NULL)) { g_printerr("ERROR: Failed to link file-source and audio-decoder !! \n"); return false; } if(!gst_element_link_many (m_audioDecoder, m_volume, NULL)) { g_printerr("ERROR: Failed to link audio-decoder and volume !! \n"); return false; } if(!gst_element_link_many (m_volume, m_audioConverter, NULL)) { g_printerr("ERROR: Failed to link audio-decoder and audio-converter !! \n"); return false; } if(!gst_element_link_many (m_audioConverter, m_sink, NULL)) { g_printerr("ERROR: Failed to link audio-converter and sink !! \n"); return false; } } /* Prepare the pipeline */ gst_element_set_state(m_pipeline, GST_STATE_READY); gst_element_set_state(m_pipeline, GST_STATE_PAUSED); } bus_call(GstBus *bus, GstMessage *msg, gpointer data) { CMediaPlayer *ptr = (CMediaPlayer*)(data); switch(GST_MESSAGE_TYPE(msg)) { case GST_MESSAGE_EOS: // Reset the position of the stream gst_element_set_state (ptr->m_pipeline, GST_STATE_READY); gst_element_set_state (ptr->m_pipeline, GST_STATE_PAUSED); g_message("GST_MESSAGE_EOS \n"); break; case GST_MESSAGE_ERROR: gchar *debug; GError *error; gst_message_parse_error (msg, &error, &debug); g_free (debug); g_printerr ("ERROR: %s\n", error->message); g_error_free (error); break; default: g_message("default \n"); break; } bus = bus; // prevent "unused" warning return TRUE; } slot_play() { m_gstReturnValue = gst_element_set_state (m_pipeline, GST_STATE_PLAYING); if(m_gstReturnValue == GST_STATE_CHANGE_FAILURE) { g_printerr("ERROR: Cannot play !! \n"); } } slot_pause() { m_gstReturnValue = gst_element_set_state (m_pipeline, GST_STATE_PAUSED); if(m_gstReturnValue == GST_STATE_CHANGE_FAILURE) { g_printerr("ERROR: Cannot pause !! \n"); } } slot_stop() { m_gstReturnValue = gst_element_set_state (m_pipeline, GST_STATE_READY); m_gstReturnValue = gst_element_set_state (m_pipeline, GST_STATE_PAUSED); if(m_gstReturnValue == GST_STATE_CHANGE_FAILURE) { g_printerr("ERROR: Cannot stop !! \n"); } } slot_setVolume(int vol_i) { vol_i = (vol_i > 10) ? 10 : (vol_i < 0) ? 0 : vol_i; g_object_set(G_OBJECT(m_volume), "volume", (gdouble(vol_i)/10), NULL); } CMediaPlayer:：CMediaPlayer（QString路径） { gst_init（空，空）； 创建元素（路径）； } createElements（QString和path） { /*创建gstreamer元素*/ m_pipeline=gst_pipeline_new（“音频播放器”）； m_fileSource=gst_element_factory_make（“filesrc”，“文件源”）； m_audioDecoder=gst_元件_工厂_制造（“mad”、“mp3解码器”）； m_volume=gst_element_factory_make（“卷”、“卷名”）； m_audioConverter=gst_元件_工厂制造（“audioconvert”、“audio converter”）； m_sink=gst_元素_工厂制造（“ALASINK”，“音频输出”）； 如果（！m|U管道| |！m|U文件源| |！m|U音频解码器| |！m|U音量| |！m| U音频转换器| |！m|U接收器）{ g_printerr（“无法创建一个或多个元素！！\n”）； 返回false； } /*铺设管道*/ 否则{ /*在总线上设置消息处理程序*/ GstBus*总线=gst_管道_get_总线（gst_管道（m_管道））； gst_总线_添加_手表（总线、总线呼叫、m_环路）； 商品及服务税（巴士）； g_object_set（g_object（m_fileSource），“location”，path.toLatin1（）.data（），NULL）； /*将所有元素添加到管道中*/ gst_bin_add_many（gst_bin（m_管道）、m_文件源、m_音频解码器、m_音量、m_音频转换器、m_接收器、NULL）； /*将元素链接在一起*/ if（！gst_元素_链接_多个（m_文件源，m_音频解码器，NULL））{ g_printerr（“错误：链接文件源和音频解码器失败！！\n”）； 返回false； } if（！gst\u元素\u链接\u多（m\u音频解码器，m\u音量，空））{ g_printerr（“错误：无法链接音频解码器和音量！！\n”）； 返回false； } 如果（！gst_元素_链接_多个（m_音量，m_音频转换器，空））{ g_printerr（“错误：链接音频解码器和音频转换器失败！！\n”）； 返回false； } if（！gst_元素_链接_多（m_音频转换器、m_接收器、空））{ g_printerr（“错误：链接音频转换器和接收器失败！！\n”）； 返回false； } } /*准备管道*/ gst_元件_设置_状态（m_管道，gst_状态_就绪）； gst_元素_设置_状态（m_管道，gst_状态_暂停）； } 总线调用（GstBus*总线、GstMessage*消息、gpointer数据）{ CMediaPlayer*ptr=（CMediaPlayer*）（数据）； 开关（GST\信息\类型（msg）） { 案例GST\信息\ EOS： //重置流的位置 gst_元素_设置_状态（ptr->m_管道，gst_状态_就绪）； gst\元素\设置\状态（ptr->m\管道，gst\状态\暂停）； g_消息（“GST_消息_EOS\n”）； 打破 案例GST\u消息\u错误： gchar*调试； GError*错误； gst\消息\解析\错误（消息、错误和调试）； g_自由（调试）； g_printerr（“错误：%s\n”，错误->消息）； g_无错误（错误）； 打破 违约： g_消息（“默认\n”）； 打破 } bus=bus；//防止“未使用”警告 返回TRUE； } 吃角子老虎{ m_gstReturnValue=gst_元素_集合_状态（m_管道、gst_状态_播放）； 如果（m_gstReturnValue==GST_状态_更改_失败） { g_printerr（“错误：无法播放！！\n”）； } } 时隙暂停（）{ m_gstReturnValue=gst_元素_设置_状态（m_管道，gst_状态_暂停）； 如果（m_gstReturnValue==GST_状态_更改_失败） { g_printerr（“错误：无法暂停！！\n”）； } } 槽_停止（）{ m_gstReturnValue=gst_元素_集合_状态（m_管道，gst_状态_就绪）； m_gstReturnValue=gst_元素_设置_状态（m_管道，gst_状态_暂停）； 如果（m_gstReturnValue==GST_状态_更改_失败） { g_printerr（“错误：无法停止！！\n”）； } } 插槽设置卷（int vol i）{ 第一卷=（第一卷>10）？10：（第一卷

当我运行应用程序时，它的行为异常。有时它玩，有时不玩。当它不播放时，我会从中获取信息：

0:01:12.000176325 31988   0x5e3000 INFO               GST_EVENT gstevent.c:1244:gst_event_new_latency: creating latency event 0:00:00.000000000
0:01:12.000953562 31988   0x5e3000 INFO                     bin gstbin.c:2502:gst_bin_do_latency_func:<audio-player> configured latency of 0:00:00.000000000
0:01:12.001444706 31988   0x5e3000 INFO              GST_STATES gstbin.c:2230:gst_bin_element_set_state:<audio-output> current PAUSED pending VOID_PENDING, desired next PLAYING
0:01:12.004258709 31988   0x5e3000 INFO              GST_STATES gstelement.c:2328:gst_element_continue_state:<audio-output> completed state change to PLAYING
0:01:12.004433239 31988   0x5e3000 INFO              GST_STATES gstelement.c:2233:_priv_gst_element_state_changed:<audio-output> notifying about state-changed PAUSED to PLAYING (VOID_PENDING pending)
0:01:12.004624124 31988   0x5e3000 INFO              GST_STATES gstbin.c:2673:gst_bin_change_state_func:<audio-player> child 'audio-output' changed state to 4(PLAYING) successfully
0:01:12.004783134 31988   0x5e3000 INFO              GST_STATES gstbin.c:2230:gst_bin_element_set_state:<audio-converter> current PAUSED pending VOID_PENDING, desired next PLAYING
0:01:12.004904644 31988   0x5e3000 INFO              GST_STATES gstelement.c:2328:gst_element_continue_state:<audio-converter> completed state change to PLAYING
0:01:12.004990634 31988   0x5e3000 INFO              GST_STATES gstelement.c:2233:_priv_gst_element_state_changed:<audio-converter> notifying about state-changed PAUSED to PLAYING (VOID_PENDING pending)
0:01:12.005134540 31988   0x5e3000 INFO              GST_STATES gstbin.c:2673:gst_bin_change_state_func:<audio-player> child 'audio-converter' changed state to 4(PLAYING) successfully
0:01:12.005267925 31988   0x5e3000 INFO              GST_STATES gstbin.c:2230:gst_bin_element_set_state:<volume-name> current PAUSED pending VOID_PENDING, desired next PLAYING
0:01:12.005386310 31988   0x5e3000 INFO              GST_STATES gstelement.c:2328:gst_element_continue_state:<volume-name> completed state change to PLAYING
0:01:12.005483653 31988   0x5e3000 INFO              GST_STATES gstelement.c:2233:_priv_gst_element_state_changed:<volume-name> notifying about state-changed PAUSED to PLAYING (VOID_PENDING pending)
0:01:12.005634851 31988   0x5e3000 INFO              GST_STATES gstbin.c:2673:gst_bin_change_state_func:<audio-player> child 'volume-name' changed state to 4(PLAYING) successfully
0:01:12.005785006 31988   0x5e3000 INFO              GST_STATES gstbin.c:2230:gst_bin_element_set_state:<mp3-decoder> current PAUSED pending VOID_PENDING, desired next PLAYING
0:01:12.005916673 31988   0x5e3000 INFO              GST_STATES gstelement.c:2328:gst_element_continue_state:<mp3-decoder> completed state change to PLAYING
0:01:12.006004329 31988   0x5e3000 INFO              GST_STATES gstelement.c:2233:_priv_gst_element_state_changed:<mp3-decoder> notifying about state-changed PAUSED to PLAYING (VOID_PENDING pending)
0:01:12.006142245 31988   0x5e3000 INFO              GST_STATES gstbin.c:2673:gst_bin_change_state_func:<audio-player> child 'mp3-decoder' changed state to 4(PLAYING) successfully
0:01:12.006259484 31988   0x5e3000 INFO              GST_STATES gstbin.c:2230:gst_bin_element_set_state:<file-source> current PAUSED pending VOID_PENDING, desired next PLAYING
0:01:12.006381567 31988   0x5e3000 INFO              GST_STATES gstelement.c:2328:gst_element_continue_state:<file-source> completed state change to PLAYING
0:01:12.006465942 31988   0x5e3000 INFO              GST_STATES gstelement.c:2233:_priv_gst_element_state_changed:<file-source> notifying about state-changed PAUSED to PLAYING (VOID_PENDING pending)
0:01:12.006599379 31988   0x5e3000 INFO              GST_STATES gstbin.c:2673:gst_bin_change_state_func:<audio-player> child 'file-source' changed state to 4(PLAYING) successfully
0:01:12.006726983 31988   0x5e3000 INFO              GST_STATES gstelement.c:2328:gst_element_continue_state:<audio-player> completed state change to PLAYING
0:01:12.006812868 31988   0x5e3000 INFO              GST_STATES gstelement.c:2233:_priv_gst_element_state_changed:<audio-player> notifying about state-changed PAUSED to PLAYING (VOID_PENDING pending)

0:01:12.000176325 31988 0x5e3000信息GST\U事件gstevent.c:1244:GST\U事件新延迟：创建延迟事件0:00:00.000000000
0:01:12.000953562 31988 0x5e3000信息bin gstbin.c:2502:gst\u bin\u do\u latency\u func:。但这没用

我错过了什么？我是gstreamer的新手。任何指针都会非常有用。
好的，这对我来说很好，一直在玩

#include <gst/gst.h>
#include <glib.h>

int createElements(char *path)
{

    /* Create gstreamer elements */
    GstElement *m_pipeline  = gst_pipeline_new("audio-player");
    GstElement *m_fileSource = gst_element_factory_make("filesrc", "file-source");
    GstElement *m_audioDecoder = gst_element_factory_make("mad", "mp3-decoder");
    GstElement *m_volume = gst_element_factory_make("volume", "volume-name");
    GstElement *m_audioConverter = gst_element_factory_make("audioconvert", "audio-converter");
    GstElement *m_sink = gst_element_factory_make("alsasink", "audio-output");

    if (!m_pipeline || !m_fileSource || !m_audioDecoder || !m_volume || !m_audioConverter || !m_sink) {
            g_printerr ("One or more elements could not be created !! \n");
            return 0;
    } else {
            g_object_set (G_OBJECT (m_fileSource), "location", path, NULL);

            gst_bin_add_many (GST_BIN (m_pipeline), m_fileSource, m_audioDecoder, m_volume, m_audioConverter, m_sink, NULL);

            if(!gst_element_link_many (m_fileSource, m_audioDecoder, NULL)) {
                    g_printerr("ERROR: Failed to link file-source and audio-decoder !! \n");
                    return 0;
            }
            if(!gst_element_link_many (m_audioDecoder, m_volume, NULL)) {
                    g_printerr("ERROR: Failed to link audio-decoder and volume !! \n");
                    return 0;
            }
            if(!gst_element_link_many (m_volume, m_audioConverter, NULL)) {
                    g_printerr("ERROR: Failed to link audio-decoder and audio-converter !! \n");
                    return 0;
            }
            if(!gst_element_link_many (m_audioConverter, m_sink, NULL)) {
                    g_printerr("ERROR: Failed to link audio-converter and sink !! \n");
                    return 0;
            }
    }

    gst_element_set_state(m_pipeline, GST_STATE_PAUSED);
    sleep(3);
    gst_element_set_state(m_pipeline, GST_STATE_PLAYING);
    sleep(1);
    gst_element_set_state(m_pipeline, GST_STATE_PAUSED);
    sleep(2);
    gst_element_set_state(m_pipeline, GST_STATE_PLAYING);

    return 1;
}


int main(int argc, char **argv) {
    GMainLoop *loop = g_main_loop_new (NULL, FALSE);
    gst_init(&argc, &argv);
    createElements(argv[1]);
    g_main_loop_run (loop);
    return 0;
}

使用./alsa_player file.mp3运行

我正在使用gstreamer1.6，但我认为这段代码对于任何1.x gstreamer都能完美运行

更新2：
您还可以尝试使用gst play命令来执行指定ALASINK的相同任务：

gst-play-1.0 japaka.mp3--audiosink=alsasink

使用空间暂停和播放
 这对您来说有趣吗
gst-launch-1.0 filesrc location=/home/../some.mp3！疯狂的音量！音频转换！alsasink
？你能把你呼叫的地方的密码也显示出来吗？@otopolsky:是的。命令运行良好。我在构造函数中调用gst_int。我已经编辑了我的帖子，把它也包括在内。我按照你的建议运行了它。如果只需要播放文件，代码似乎就可以工作。当我暂停/停止然后再次播放时，麻烦就来了。我还收到了这些警告：0:00:00.238477854 4109 0x1f84320 WARN alsa conf.c:4705:snd_config_expand:alsalib error:Unknown parameters{AES0 0x02 AES1 0x82 AES2 0x00 AES3 0x02}0:00.238729364 4109 0x1f84320 WARN alsa pcm.c:2239:snd_pcm_open_update:alsalib error
gcc -Wall alsa_player.c -o alsa_player $(pkg-config --cflags --libs gstreamer-1.0)