我有一个简单的gstreamer管道,可以播放mp4文件,并且它支持搜索。我已经制作了该管道的另一个版本,这个版本是使用typefind元素动态创建的demux。使用此版本的管道,查找似乎无效。这是Python中这两个版本的最低版本:
以下是管道图:
请注意,实际播放在两个管道中都可以。仅搜索在动态版本中不起作用。据我所知,两者之间的唯一主要区别在于,在动态管道中,将typefind连接到demux元素的焊盘处于拉动模式,而在另一个焊盘中则处于推动模式,但是我不知道这是否是相关,以及如何解决。
另一个区别是,在搜索时,动态版本中新创建的多路复用器处于播放状态,而其他元素处于暂停状态。我尝试将新的多路分解器设置为暂停状态,但这似乎并没有改变任何内容。
我能想到的最简单的代码版本如下:
工作版本:
import gi
gi.require_version('Gst', '1.0')
gi.require_version('GLib', '2.0')
from gi.repository import Gst, GLib
def demux_pad_added(element, pad, pipeline):
dec = pipeline.get_by_name('dec0')
result = pad.link(dec.get_static_pad('sink'))
if result != Gst.PadLinkReturn.OK:
print('Could not link demux to dec.')
exit(1)
print('Linked demux to dec.')
Gst.debug_bin_to_dot_file(pipeline, Gst.DebugGraphDetails.ALL, 'working')
ret = pipeline.seek_simple(Gst.Format.TIME, Gst.SeekFlags.FLUSH | Gst.SeekFlags.KEY_UNIT, 1800 * Gst.SECOND)
print('seek result:', ret)
def main():
Gst.init(None)
loop = GLib.MainLoop()
pipeline = Gst.Pipeline()
src = Gst.ElementFactory.make('filesrc', 'src0')
typefind = Gst.ElementFactory.make('typefind', 'typefind0')
demux = Gst.ElementFactory.make('qtdemux', 'demux0')
dec = Gst.ElementFactory.make('libde265dec', 'dec0')
sink = Gst.ElementFactory.make('appsink', 'sink0')
src.set_property('location', 'foo.mp4')
demux.connect('pad-added', demux_pad_added, pipeline)
elements = [src, typefind, demux, dec, sink]
for e in elements:
pipeline.add(e)
for i in range(0, len(elements) - 1):
e1, e2 = elements[i], elements[i+1]
if e1 == demux:
continue
if not e1.link(e2):
print('Could not link {} to {}.'.format(e1.name, e2.name))
exit(1)
pipeline.set_state(Gst.State.PLAYING)
loop.run()
if __name__ == '__main__':
main()
查找不起作用的版本:
import gi
gi.require_version('Gst', '1.0')
gi.require_version('GLib', '2.0')
from gi.repository import Gst, GLib
def demux_pad_added(element, pad, pipeline):
dec = pipeline.get_by_name('dec0')
result = pad.link(dec.get_static_pad('sink'))
if result != Gst.PadLinkReturn.OK:
print(pad.name, dec.get_static_pad('sink').name)
print('Could not link demux to dec.')
exit(1)
print('Linked demux to dec.')
Gst.debug_bin_to_dot_file(pipeline, Gst.DebugGraphDetails.ALL, 'not-working')
ret = pipeline.seek_simple(Gst.Format.TIME, Gst.SeekFlags.FLUSH | Gst.SeekFlags.KEY_UNIT, 1800 * Gst.SECOND)
print('seek result:', ret)
def typefind_have_type(typefind, probability, caps, pipeline):
videofmt = caps.to_string()
if ',' in videofmt:
videofmt = videofmt.split(',')[0]
demux_name = {
'video/quicktime': 'qtdemux',
'video/x-matroska': 'matroskademux',
'video/x-msvideo': 'avidemux',
}.get(videofmt, None)
if not demux_name:
print('Unknown input file format: {}'.format(videofmt))
exit(1)
demux = Gst.ElementFactory.make(demux_name, 'demux0')
pipeline.add(demux)
demux.connect('pad-added', demux_pad_added, pipeline)
demux.set_state(Gst.State.PLAYING)
if not typefind.link(demux):
print('Could not link typefind to demux.')
exit(1)
def main():
Gst.init(None)
loop = GLib.MainLoop()
pipeline = Gst.Pipeline()
src = Gst.ElementFactory.make('filesrc', 'src0')
typefind = Gst.ElementFactory.make('typefind', 'typefind0')
demux = object() # dummy
dec = Gst.ElementFactory.make('libde265dec', 'dec0')
sink = Gst.ElementFactory.make('appsink', 'sink0')
src.set_property('location', 'foo.mp4')
typefind.connect('have-type', typefind_have_type, pipeline)
elements = [src, typefind, demux, dec, sink]
for e in elements:
if e != demux:
pipeline.add(e)
for i in range(0, len(elements) - 1):
e1, e2 = elements[i], elements[i+1]
if e1 == demux or e2 == demux:
continue
if not e1.link(e2):
print('Could not link {} to {}.'.format(e1.name, e2.name))
exit(1)
pipeline.set_state(Gst.State.PLAYING)
loop.run()
if __name__ == '__main__':
main()
任何帮助将不胜感激。
答案 0 :(得分:1)
我设法自己找到了解决方法。将typefind链接到demux之后,我只需要将demux.set_state(...)
调用移到typefind回调的末尾。新的typefind回调现在看起来像这样:
def typefind_have_type(typefind, probability, caps, pipeline):
videofmt = caps.to_string()
if ',' in videofmt:
videofmt = videofmt.split(',')[0]
demux_name = {
'video/quicktime': 'qtdemux',
'video/x-matroska': 'matroskademux',
'video/x-msvideo': 'avidemux',
}.get(videofmt, None)
if not demux_name:
print('Unknown input file format: {}'.format(videofmt))
exit(1)
demux = Gst.ElementFactory.make(demux_name, 'demux0')
pipeline.add(demux)
demux.connect('pad-added', demux_pad_added, pipeline)
#demux.set_state(Gst.State.PLAYING) # moved from here to further down
if not typefind.link(demux):
print('Could not link typefind to demux.')
exit(1)
demux.set_state(Gst.State.PLAYING) # <--- new location