Question

这里,Im指挥试图复制:

gst-launch filesrc location=test.flac ! flacdec ! lame ! filesink location=test.mp3

当我掌管这一指挥时,它工作得很好。我曾尝试用无uck的装饰器复制这种弹药。我没有发现这些文字中的任何错误,但他们没有按预期工作:

当我管理这本文字时,我只收到一份空洞的MP3文件:

import gst
pipeline = gst.parse_launch( filesrc location="test.flac" ! flacdec ! lame ! filesink location="test.mp3" )
pipeline.set_state(gst.STATE_PLAYING)

当我管理这封信件时,我收到了腐败的议员3号档案:

import gst

converter = gst.Pipeline( converter )

source = gst.element_factory_make( filesrc ,  file-source )
source.set_property( location ,  test.flac )

decoder = gst.element_factory_make( flacdec ,  decoder )

encoder = gst.element_factory_make( lame ,  encoder )

sink = gst.element_factory_make( filesink ,  sink )
sink.set_property( location ,  test.mp3 )

converter.add(source, decoder, encoder, sink)

source.link(sink)

converter.set_state(gst.STATE_PLAYING)

任何人都知道我做错了什么?

Answer 1

Gstreamer uses GObject as a framework, so you need to run gobject.MainLoop() to start message flow in pipeline:

import gobject
import gst
pipeline = gst.parse_launch( filesrc location="test.flac" ! flacdec ! lame ! filesink location="test.mp3" )
pipeline.set_state(gst.STATE_PLAYING)

gobject.threads_init()
gobject.MainLoop().run()

In the second example you also need to run MainLoop and link all the pipeline elements (e.g. with element_link_many). You connected only source to sink, so your actual pipeline is just filesrc ! filesink.

兹更正成法典:

import gobject
import gst

converter = gst.Pipeline( converter )

source = gst.element_factory_make( filesrc ,  file-source )
source.set_property( location ,  test.flac )

decoder = gst.element_factory_make( flacdec ,  decoder )
encoder = gst.element_factory_make( lame ,  encoder )

sink = gst.element_factory_make( filesink ,  sink )
sink.set_property( location ,  test.mp3 )

converter.add(source, decoder, encoder, sink)
gst.element_link_many(source, decoder, encoder, sink)

converter.set_state(gst.STATE_PLAYING)

gobject.threads_init()
gobject.MainLoop().run()

Answer 2

Some people end up at this answer looking for the command line / bash solution. Here is a good conversion script.

#!/bin/bash

#Take a lossless flac audio track from and transcode it as a constant rate mp3 playable on some older audio equipment that can t play mp4s or variable bit rate mp3 s.

if [ -z "$1" ];then
   echo usage: $0 [infile.flac]
   exit
fi

INFILE=$(basename $1)
WKDIR=$(dirname $1)
OUTFILE=$WKDIR/$( echo $INFILE | sed  s/.flac// ).mp3

#play ===================
#gst- launch filesrc location=1.flac 
#! flacdec 
#! autoaudiosink

#transcode ==============
gst-launch filesrc location=$INFILE 
! queue 
! flacdec 
! audioconvert 
! audioresample 
! lamemp3enc quality=2 target=bitrate bitrate=192 cbr=true 
! id3v2mux 
! filesink location=$OUTFILE

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