音频

播放音频

树莓派中用python播放音频

前提：

树莓派中，先去安装vlc：

sudo apt-get install vlc

代码：

import vlc
instance = vlc.Instance('--aout=alsa')
p = instance.media_player_new()
m = instance.media_new('/home/pi/Music/lizhongsheng_massif_live.mp3')
p.set_media(m)
p.play()

即可播放音频。

实现设置音量，暂停，继续播放等操作的代码是：

p.pause()
vlc.libvlc_audio_set_volume(p, 40)
p.play()
vlc.libvlc_audio_set_volume(p, 90)

Mac中调用mpv播放音频

播放音频：

cmdPlayer = "mpv"
cmdParaFilePath = tmpAudioFileFullPath
cmdArgList = [cmdPlayer, cmdParaFilePath]

if gCurSubProcess:
    gCurSubProcess.terminate()

gCurSubProcess = subprocess.Popen(cmdArgList)
log.debug("gCurSubProcess=%s", gCurSubProcess)

停止播放：

if audioControl == "stop":
    if gCurSubProcess:
        gCurSubProcess.terminate()

    respData = {
        audioControl: "ok"
    }

else:
    respData = {
        audioControl: "Unsupport command"
    }

获取播放效果：

if gCurSubProcess:
    isTerminated = gCurSubProcess.poll() # None
    # stdout_data, stderr_data = gCurSubProcess.communicate()
    # stdoutStr = str(stdout_data)
    # stderrStr = str(stderr_data)
    respData = {
        "isTerminated": isTerminated,
        # "stdout_data": stdoutStr,
        # "stderr_data": stderrStr,
    }

返回结果：

• 正在播放：返回isTerminated为null
• 被终止后，返回isTerminated为4
  • 

播放的效果：

mac系统中播放音频

PyCharm的console中输出当前播放的信息 -》 如果是mac的terminal中，则是覆盖式的，不会这么多行 同时弹框GUI窗口

mp3

解析mp3等音频文件得到时长信息

用库：

• audioread
  • GitHub
    • beetbox/audioread: cross-library (GStreamer + Core Audio + MAD + FFmpeg) audio decoding for Python

import audioread

try:
    audioFullFilePath = "/your/input/audio/file.mp3"

    with audioread.audio_open(audioFullFilePath) as audioFp:
        audioInfo["duration"] = audioFp.duration
        audioInfo["channels"] = audioFp.channels
        audioInfo["sampleRate"] = audioFp.samplerate

except OSError as osErr:
    logging.error("OSError when open %s error %s", audioFullFilePath, osErr)
except EOFError as eofErr:
    logging.error("EOFError when open %s error %s", audioFullFilePath, eofErr)
except audioread.DecodeError as decodeErr:
    logging.error("Decode audio %s error %s", audioFullFilePath, decodeErr)

后经整理成函数：

import audioread

def detectAudioMetaInfo(audioFullPath):
    """
        detect audio meta info: duration, channels, sampleRate
    """
    isOk = False
    errMsg = ""
    audioMetaInfo = {
        "duration": 0,
        "channels": 0,
        "sampleRate": 0,
    }

    try:
        with audioread.audio_open(audioFullPath) as audioFp:
            audioMetaInfo["duration"] = audioFp.duration
            audioMetaInfo["channels"] = audioFp.channels
            audioMetaInfo["sampleRate"] = audioFp.samplerate

            isOk = True
    except OSError as osErr:
        errMsg = "detect audio info error: %s" % str(osErr)
    except EOFError as eofErr:
        errMsg = "detect audio info error: %s" % str(eofErr)
    except audioread.DecodeError as decodeErr:
        errMsg = "detect audio info error: %s" % str(decodeErr)

    if isOk:
        return isOk, audioMetaInfo
    else:
        return isOk, errMsg

调用：

def demoDetectAudioMeta():
  curPath = os.path.dirname(__file__)
  inputAudioList = [
    "input/audio/actual_aac_but_suffix_mp3.mp3",
    "input/audio/real_mp3_format.mp3",
    "not_exist_audio.wav",
    "input/audio/fake_audio_actual_image.wav",
  ]


  for eachAudioPath in inputAudioList:
    eachAudioFullPath = os.path.join(curPath, eachAudioPath)
    isOk, errOrInfo = detectAudioMetaInfo(eachAudioFullPath)
    print("isOk=%s, errOrInfo=%s" % (isOk, errOrInfo))


if __name__ == "__main__":
  demoDetectAudioMeta()

对应的音频文件，用MediaInfo检测出的信息：

• 正常mp3
  • 
  • 
• 异常mp3：
  • 故意把png图片改成mp3
    • 

输出：

# isOk=True, errOrInfo={'duration': 637.8, 'channels': 2, 'sampleRate': 44100}
# isOk=True, errOrInfo={'duration': 2.3510204081632655, 'channels': 2, 'sampleRate': 44100}
# isOk=False, errOrInfo=detect audio info error: [Errno 2] No such file or directory: '/Users/crifan/dev/dev_root/crifan/crifanLibPython/crifanLib/demo/not_exist_audio.wav'
# isOk=False, errOrInfo=detect audio info error: