我在Vala中使用带有playbin的scaletempo时遇到了麻烦。我创建了playbin,然后创建了一个bin来存储更换默认音频接收器的其他插件。下面的示例我从pyTranscribe抓取并转换为Vala但Element.link_many导致错误,我不太清楚为什么。
我是以正确的方式来做这件事的吗?有人有任何其他建议吗?
/* SoundPlayerBackend.vala */
/* Modified code from Damien Radtke's site. http://damienradtke.org/ */
using Gst;
public class SoundPlayerBackend {
//Constants
const double PLAYBACK_RATE_MODIFIER = 2.0;
const int SEEK_SECONDS = 10;
// Method delegates for notifying SoundPlayer about certain events
protected delegate void NotifyEos();
protected delegate void NotifyError(string message);
// Pointer to our EOS delegate
protected NotifyEos on_eos;
// Pointer to our Error delegate
protected NotifyError on_error;
public static void main(string[] args){
var soundplayer = new SoundPlayerBackend();
Gst.init(ref args);
soundplayer.setUri("file:///home/codenomad/Desktop/player-project/hurricane.mp3");
soundplayer.play();
string stop = stdin.read_line ();
while (stop != "stop") {
if (stop == "pause") { soundplayer.pause(); }
else if (stop == "play") { soundplayer.play(); }
stop = stdin.read_line ();
}
}
// Read-only reference to the current sound object
public dynamic Element sound { get; private set; }
// Read-only "is playing" property
public bool is_playing { get; private set; default = false; }
// Read-only "rate" property
public double rate { get; private set; default = 1; }
public void setUri(string uri) {
// Make sure any existing allocated resources are freed
if (sound != null)
sound.set_state(Gst.State.NULL);
sound = ElementFactory.make("playbin2", "playbin");
sound.uri = uri;
var audiobin = new Bin("audioline");
var scaletempo = ElementFactory.make("scaletempo", "scaletempo");
var convert = ElementFactory.make("audioconvert", "convert");
var resample = ElementFactory.make("audioresample", "resample");
var audiosink = ElementFactory.make("autoaudiosink", "audiosink");
audiobin.add_many(scaletempo, convert, resample, audiosink);
//edited based on comment below
//Element.link_many(scaletempo, convert, resample, audiosink);
scaletempo.link_many(convert, resample, audiosink);
var pad = scaletempo.get_pad("sink");
audiobin.add_pad(new GhostPad("sink", pad));
sound.set_property("audio-sink", audiobin);
sound.get_bus().add_watch(on_event);
}
// Play the sound
public void play() {
sound.set_state(State.PLAYING);
print("Playing\n");
is_playing = true;
}
// Pause it
public void pause() {
sound.set_state(State.PAUSED);
is_playing = false;
print("Paused\n");
}
// Event bus, listens for events and responds accordingly
protected bool on_event(Gst.Bus bus, Message message) {
switch (message.type) {
case MessageType.ERROR:
GLib.Error err;
string debug;
sound.set_state(Gst.State.NULL);
is_playing = false;
message.parse_error(out err, out debug);
on_error(err.message);
break;
case MessageType.EOS:
sound.set_state(Gst.State.READY);
is_playing = false;
on_eos();
break;
default:
break;
}
return true;
}
}
我尝试使用相同的代码使所有内容保持静态,并在下面收到相同的结果/错误:
SoundPlayerBackend.vala:121.9-121.67: error: Access to instance member `Gst.Element.link_many' denied
Element.link_many(scaletempo, convert, resample, audiosink);
提前致谢!
答案 0 :(得分:1)
该行应为
scaletempo.link_many(convert, resample, audiosink);