Android7.1修改系统配置文件默认听筒输出所有声音

前言

    2014年的买的旧手机到现在一直在捣腾，尽管厂商已经时隔很多年没有更新过系统了。于是自己刷了魔趣的7.1的系统，不得不说原生android系统比手机厂商二次定制过的系统要流畅很多，但是在去年这只陪伴了很多年的旧手机终于出现了问题，扬声器没有声音了，于是拆开手机检查了半天，没有发现任何烧坏的痕迹，拆下扬声器测试也是好的，可能是尾插主板坏了吧，刮了下扬声器触点重新安上还是没有声音，没办法了，于是就想能否用听筒来播放所有声音呢？百度了下还真有这样的软件，于是就随便下了个app，点击切换成听筒模式，终于可以了。但每次重启后就要重新打开，而且有时候还会强制退出，或者用着用着听筒就没有声音了，需要重新打开软件，很麻烦。于是又想能否通过修改系统配置文件让声音都从听筒来输出呢？

正文

    答案当然是可以的，首先手机得获取root权限，然后下载个第三方文件管理器，这里用了ES文件浏览器，修改配置文件路径如下：

/etc/audio_policy.conf

打开后该配置文件内容如下：

# Global configuration section: lists input and output devices always present on the device
# as well as the output device selected by default.
# Devices are designated by a string that corresponds to the enum in audio.h

global_configuration {
  attached_output_devices AUDIO_DEVICE_OUT_EARPIECE|AUDIO_DEVICE_OUT_SPEAKER
  default_output_device AUDIO_DEVICE_OUT_SPEAKER
  attached_input_devices AUDIO_DEVICE_IN_BUILTIN_MIC|AUDIO_DEVICE_IN_BACK_MIC|AUDIO_DEVICE_IN_THIRD_MIC|AUDIO_DEVICE_IN_REMOTE_SUBMIX|AUDIO_DEVICE_IN_VOICE_CALL
}

# audio hardware module section: contains descriptors for all audio hw modules present on the
# device. Each hw module node is named after the corresponding hw module library base name.
# For instance, "primary" corresponds to audio.primary..so.
# The "primary" module is mandatory and must include at least one output with
# AUDIO_OUTPUT_FLAG_PRIMARY flag.
# Each module descriptor contains one or more output profile descriptors and zero or more
# input profile descriptors. Each profile lists all the parameters supported by a given output
# or input stream category.
# The "channel_masks", "formats", "devices" and "flags" are specified using strings corresponding
# to enums in audio.h and audio_policy.h. They are concatenated by use of "|" without space or "\n".

audio_hw_modules {
  primary {
    outputs {
      primary {
        sampling_rates 44100|48000
        channel_masks AUDIO_CHANNEL_OUT_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_OUT_EARPIECE|AUDIO_DEVICE_OUT_SPEAKER|AUDIO_DEVICE_OUT_WIRED_HEADSET|AUDIO_DEVICE_OUT_WIRED_HEADPHONE|AUDIO_DEVICE_OUT_ALL_SCO|AUDIO_DEVICE_OUT_EXTERNAL_WIFI|AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET
        flags AUDIO_OUTPUT_FLAG_PRIMARY
      }
      hdmi {
        sampling_rates 48000
        channel_masks dynamic
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_OUT_AUX_DIGITAL
        flags AUDIO_OUTPUT_FLAG_MULTI_CH
      }
      compress_offload {
        sampling_rates 11025|16000|22050|32000|44100|48000
        channel_masks AUDIO_CHANNEL_OUT_MONO|AUDIO_CHANNEL_OUT_STEREO|AUDIO_CHANNEL_OUT_2POINT1|AUDIO_CHANNEL_OUT_QUAD|AUDIO_CHANNEL_OUT_PENTA|AUDIO_CHANNEL_OUT_5POINT1|AUDIO_CHANNEL_OUT_6POINT1|AUDIO_CHANNEL_OUT_7POINT1
        formats AUDIO_FORMAT_MP3|AUDIO_FORMAT_AAC_LC|AUDIO_FORMAT_AAC_HE_V1|AUDIO_FORMAT_AAC_HE_V2|AUDIO_FORMAT_AC3|AUDIO_FORMAT_E_AC3
        devices AUDIO_DEVICE_OUT_EARPIECE|AUDIO_DEVICE_OUT_SPEAKER|AUDIO_DEVICE_OUT_WIRED_HEADSET|AUDIO_DEVICE_OUT_WIRED_HEADPHONE|AUDIO_DEVICE_OUT_ALL_SCO|AUDIO_DEVICE_OUT_EXTERNAL_WIFI|AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET
        flags AUDIO_OUTPUT_FLAG_DIRECT|AUDIO_OUTPUT_FLAG_COMPRESS_OFFLOAD|AUDIO_OUTPUT_FLAG_NON_BLOCKING
      }
    }
    inputs {
      primary {
        sampling_rates 8000|11025|12000|16000|22050|24000|32000|44100|48000
        channel_masks AUDIO_CHANNEL_IN_MONO|AUDIO_CHANNEL_IN_STEREO|AUDIO_CHANNEL_IN_FRONT_BACK|AUDIO_CHANNEL_IN_VOICE_UPLINK|AUDIO_CHANNEL_IN_VOICE_DNLINK
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_IN_BUILTIN_MIC|AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET|AUDIO_DEVICE_IN_WIRED_HEADSET|AUDIO_DEVICE_IN_WIRED_HEADPHONE|AUDIO_DEVICE_IN_AUX_DIGITAL|AUDIO_DEVICE_IN_VOICE_CALL|AUDIO_DEVICE_IN_BACK_MIC|AUDIO_DEVICE_IN_THIRD_MIC
      }
    }
  }
  a2dp {
    outputs {
      a2dp {
        sampling_rates 44100
        channel_masks AUDIO_CHANNEL_OUT_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_OUT_ALL_A2DP
      }
    }
    inputs {
      a2dp {
        sampling_rates 44100|48000
        channel_masks AUDIO_CHANNEL_IN_MONO|AUDIO_CHANNEL_IN_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_IN_BLUETOOTH_A2DP
      }
    }
  }
  usb {
    outputs {
      usb_accessory {
        sampling_rates 44100
        channel_masks AUDIO_CHANNEL_OUT_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_OUT_USB_ACCESSORY
      }
      usb_device {
        sampling_rates 44100|48000
        channel_masks dynamic
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_OUT_USB_DEVICE|AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET
      }
    }
    inputs {
      usb_device {
        sampling_rates dynamic
        channel_masks AUDIO_CHANNEL_IN_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_IN_USB_DEVICE
      }
    }
  }
  tms {
    outputs {
      tms {
        sampling_rates 44100
        channel_masks AUDIO_CHANNEL_OUT_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_OUT_EXTERNAL_TMS
      }
    }
    inputs {
      tms {
        sampling_rates 44100
        channel_masks AUDIO_CHANNEL_IN_MONO|AUDIO_CHANNEL_IN_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_IN_EXTERNAL_TMS
      }
    }
  }
  r_submix {
    outputs {
      submix {
        sampling_rates 48000
        channel_masks AUDIO_CHANNEL_OUT_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_OUT_REMOTE_SUBMIX
      }
    }
    inputs {
      submix {
        sampling_rates 48000
        channel_masks AUDIO_CHANNEL_IN_STEREO
        formats AUDIO_FORMAT_PCM_16_BIT
        devices AUDIO_DEVICE_IN_REMOTE_SUBMIX
      }
    }
  }
}

修改以下代码即可：

global_configuration {
  attached_output_devices AUDIO_DEVICE_OUT_EARPIECE|AUDIO_DEVICE_OUT_SPEAKER //输出设备
  default_output_device AUDIO_DEVICE_OUT_SPEAKER //默认输出设备
  attached_input_devices AUDIO_DEVICE_IN_BUILTIN_MIC|AUDIO_DEVICE_IN_BACK_MIC|AUDIO_DEVICE_IN_THIRD_MIC|AUDIO_DEVICE_IN_REMOTE_SUBMIX|AUDIO_DEVICE_IN_VOICE_CALL //输入设备
}

将上面代码修改为以下代码：

global_configuration {
  attached_output_devices AUDIO_DEVICE_OUT_EARPIECE //直接删掉扬声器输出方式，剩下听筒输出方式
  default_output_device AUDIO_DEVICE_OUT_EARPIECE //默认输出设备修改为听筒
  attached_input_devices AUDIO_DEVICE_IN_BUILTIN_MIC|AUDIO_DEVICE_IN_BACK_MIC|AUDIO_DEVICE_IN_THIRD_MIC|AUDIO_DEVICE_IN_REMOTE_SUBMIX|AUDIO_DEVICE_IN_VOICE_CALL //输入设备无需修改
}

修改完后保存重启手机，重启后打开音乐播放器，音乐成功从听筒播放出来了。

Android系统的最大魅力就是可玩性很高，可以随意修改各种文件，甚至开发app的成本也不高，有需要可以自己开发出一个app来玩，但是也有缺点，就是国内的很多厂商把原生Android系统定制的很臃肿，还出现了各种BUG，植入了各种广告，令人很是头疼。还有就是国内没有Google，无法使用Google服务和Google Play，导致应用质量下降，也没有了统一推送机制，各种app服务在后台随意运行着，最终占用了大量的运行内存，还影响了手机的续航，特别是某些毒瘤app，很臃肿，后台开的服务还不止一两个，甚至还搞出来一套服务间相互唤醒机制，真的很无语。