如何在gstreamer-1.0中获得字幕索引号？

Question

使用gst-发现者，我可以得到一个在mkv文件中可用的字幕列表，但它们的出现似乎是随机的顺序。

有人知道如何使用python来获取每个子标题流的索引吗？

一旦索引被知道，一个简单的

self.pipeline.set_property("current-text",subno)

将更改正在使用的子标题流。

下面是一个简单的模拟，播放一个mkv并列出可用的字幕：

#!/usr/bin/env python
import time
from gi.repository import Gst
from gi.repository import GstPbutils

Gst.init(None)
discoverer = GstPbutils.Discoverer()
uri='file:///home/rolf/H.mkv'
info = discoverer.discover_uri(uri)
for x in info.get_subtitle_streams():
    print x.get_language()
pipeline=Gst.ElementFactory.make("playbin", "playbin")
pipeline.set_property('uri',uri)
pipeline.set_state(Gst.State.PLAYING)
time.sleep(2)
subs = pipeline.get_property('n-text')
print "there are ", subs, " Subtitles"
auds = pipeline.get_property('n-audio')
print "there are ", auds, " Audio streams"
vids = pipeline.get_property('n-video')
print "there are ", vids, " Video Streams"
subc = pipeline.get_property('current-text')
print "Currently using ", subc, " Subtitle set"
dur = int(info.get_duration())/Gst.SECOND
hh = int(dur/3600)
mm, ss = (divmod(int(divmod(dur,3600)[1]),60))
print("Duration : %02d:%02d:%02d" % (hh,mm,ss))
time.sleep(dur)    

Answer 1

这里有一个工作解决方案，不依赖于gst-发现者-1.0

更新为python3

#!/usr/bin/env python
import time
import gi
gi.require_version('Gst', '1.0')
gi.require_version('GstTag', '1.0')
gi.require_version('GstVideo', '1.0')
from gi.repository import Gst, GstTag
from gi.repository import GstVideo
Gst.init(None)
uri='file:///home/rolf/H.mkv'
pipeline=Gst.ElementFactory.make("playbin", "playbin")
pipeline.set_property('uri',uri)

suburi = "file:///home/rolf/H.srt"
suburi = pipeline.set_property('suburi', suburi)

pipeline.set_state(Gst.State.PLAYING)
time.sleep(1.0)
subs = pipeline.get_property('n-text')
auds = pipeline.get_property('n-audio')
vids = pipeline.get_property('n-video')
print (vids, "Video Streams ", auds, "Audio Streams ", subs, "Subtitle Streams")
subc = pipeline.get_property('current-text')

dur = (pipeline.query_duration(Gst.Format.TIME)[1]) / Gst.SECOND  
hh = int(dur/3600)
mm, ss = (divmod(int(divmod(dur,3600)[1]),60))
print("Duration : %02d:%02d:%02d" % (hh,mm,ss))
for x in range(subs):
    tags = pipeline.emit("get-text-tags", x)
    if tags:
        for i in range(tags.n_tags()):
            if tags.nth_tag_name(i) == "language-code":
                name = tags.nth_tag_name(i)
        if name == "language-code":
            current_code = tags.get_string(name)[1]
            if current_code != "und":
                language = GstTag.tag_get_language_name(current_code)
            else:
                language = "??"
            print(current_code, language)
    else:
        print( "No subtitle tags listed")
pipeline.set_property("current-text", 9)
print( "Currently using Subtitle set ", pipeline.get_property('current-text'))
time.sleep(dur) 

输出

1 Video Streams  1 Audio Streams  10 Subtitle Streams
Duration : 01:36:40
No subtitle tags listed
en English
ro Romanian; Moldavian; Moldovan
da Danish
cs Czech
hu Hungarian
bg Bulgarian
pl Polish
sl Slovenian
el Greek, Modern (1453-)
Currently using Subtitle set  9

对No subtitle tags listed的引用是对手动附加的字幕文件H.srt的引用。

Answer 2

在python中，您可以通过使用索引获得每个字幕流，例如：

info.get_subtitle_streams()[0]
info.get_subtitle_streams()[1]
etc...

我用迭代扩展了您的示例，虽然列出了演示的字幕列表。您仍然需要决定使用什么索引。

#!/usr/bin/env python
import time
from gi.repository import Gst
from gi.repository import GstPbutils

Gst.init(None)
discoverer = GstPbutils.Discoverer()
uri='file:///home/linuxencoder/sintel.mkv'
info = discoverer.discover_uri(uri)
mysublist = info.get_subtitle_streams()
i=0
for x in mysublist:
    print (x.get_language(), i, info.get_subtitle_streams()[i].get_language())
    i+=1
pipeline=Gst.ElementFactory.make("playbin", "playbin")
pipeline.set_property('uri',uri)
pipeline.set_state(Gst.State.PLAYING)
time.sleep(2)
subs = pipeline.get_property('n-text')
print "there are ", subs, " Subtitles"
auds = pipeline.get_property('n-audio')
print "there are ", auds, " Audio streams"
vids = pipeline.get_property('n-video')
print "there are ", vids, " Video Streams"
pipeline.set_property("current-text", 3)
subc = pipeline.get_property('current-text')
print "Currently using ", subc, " subtitle set. Sub name:", mysublist[subc].get_language()
dur = int(info.get_duration())/Gst.SECOND
hh = int(dur/3600)
mm, ss = (divmod(int(divmod(dur,3600)[1]),60))
print("Duration : %02d:%02d:%02d" % (hh,mm,ss))
time.sleep(dur)