Sailfish OS下的gstreamer没有输出声音
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【中文标题】Sailfish OS下的gstreamer没有输出声音【英文标题】:Gstreamer under Sailfish OS no output sound 【发布时间】:2015-01-20 07:39:58 【问题描述】:我正在为 Sailfish OS 开发音频播放器,并尝试通过 gstreamer 播放文件,但问题:没有声音。
我通过控制台检查了 gstream:
gst-launch-0.10 filesrc location=/path/to/file.ogg !解码器! 自动音频接收器
而且运行良好!
我测试了将音频文件转换为音频文件:
int
main (int argc,
char *argv[])
GstElement *pipeline;
GstBus *bus;
GstMessage *msg;
gst_init (&argc, &argv);
pipeline = gst_parse_launch ("filesrc location=/home/nemo/Music/Ringtones/Myfile.mp3 ! decodebin ! audioconvert ! vorbisenc ! oggmux ! filesink location=test.ogg", NULL);
gst_element_set_state (pipeline, GST_STATE_PLAYING);
bus = gst_element_get_bus (pipeline);
msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, (GstMessageType)(GST_MESSAGE_ERROR | GST_MESSAGE_EOS));
if (msg != NULL)
gst_message_unref (msg);
gst_object_unref (bus);
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
return 0;
而且运行良好!
但是,当我尝试播放时,没有声音:
pipeline = gst_parse_launch ("filesrc location=/home/nemo/Music/Ringtones/Myfile.mp3 ! decodebin ! audioconvert ! autoaudiosink", NULL);
Gstreamer 版本:0.10
【问题讨论】:
【参考方案1】:问题是因为资源需要在使用前获取:
gst-launch 在资源策略配置中被静态设置为“播放器”,因此无需任何额外工作即可运行。
但是,当您创建自己的应用程序时,您需要自己获取音频播放资源。
如果您正在开发纯 C 应用程序,请检查 https://github.com/nemomobile/libaudioresource 或为 Qt 应用程序检查 https://github.com/nemomobile/libaudioresource-qt。
例子:
#include <gst/gst.h>
#include <audioresource.h>
#include <glib.h>
#include <unistd.h>
#include <stdio.h>
/*
* Dependencies glib2-devel, libaudioresource-devel, gstreamer-devel.
* Compile with:
* gcc `pkg-config --cflags --libs gstreamer-0.10` `pkg-config --cflags --libs audioresource` `pkg-config --cflags --libs glib-2.0` gst-example.c -o gst-example
*
* Check https://github.com/nemomobile/libaudioresource
*/
static GstElement *pipeline;
static int got_reply = 0;
static void on_acquired(audioresource_t *audio_resource, bool acquired, void *user_data)
got_reply = 1;
printf("on_acquired: %s\n", acquired ? "true" : "false");
if (acquired)
// start playback here
printf("start playback\n");
gst_element_set_state (pipeline, GST_STATE_PLAYING);
else
// stop playback here
static void naive_wait()
got_reply = 0;
while (!got_reply)
g_main_context_iteration(NULL, false);
usleep(1000);
int main(int argc, char *argv[])
audioresource_t *resource;
void *user_data = NULL;
char tmp[1024];
GstBus *bus;
GstMessage *msg;
if (argc < 2)
printf("audio file argument needed.\n");
return 1;
gst_init (&argc, &argv);
printf("initialize audioresource for media player\n");
resource = audioresource_init(AUDIO_RESOURCE_MEDIA, on_acquired, user_data);
snprintf(tmp, 1024, "filesrc location=%s ! decodebin ! audiocovert ! autoaudiosink", argv[1]);
printf("create pipeline: %s\n", tmp);
pipeline = gst_parse_launch (tmp, NULL);
printf("acquire audioresource..\n");
// When you want to start playback
audioresource_acquire(resource);
// Wait for the reply for acquire..
naive_wait();
bus = gst_element_get_bus (pipeline);
msg = gst_bus_timed_pop_filtered (bus, GST_CLOCK_TIME_NONE, (GstMessageType)(GST_MESSAGE_ERROR | GST_MESSAGE_EOS));
if (msg != NULL)
gst_message_unref (msg);
gst_object_unref (bus);
gst_element_set_state (pipeline, GST_STATE_NULL);
gst_object_unref (pipeline);
printf("release audioresource..\n");
audioresource_release(resource);
// Wait for release..
naive_wait();
// When you close your application
audioresource_free(resource);
return 0;
感谢 Juho Hämäläinen 的解答!
【讨论】:
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