微信语音编解码实现（一）—— silk 移植

微信语音编解码实现

• （一）—— silk 移植
• （二）—— 支持微信语音
• （三）—— lame 移植
• （四）—— 整合 so 库
• （五）——工作线程编解码

配套源码

WeChatVoiceCodec

关于 silk

       silk 是 skype 开源的一款语音编解码器，被微信的语音文件所采用。

移植步骤

1、下载 silk 源码

       silk 的官方网站 http://developer.skype.com/silk 现在已经无法访问，但是 github 上可以找到别人备份的版本，源码下载通道。

2、拷贝源码到工程

       下载完成后，解压，将 SILK_SDK_SRC_ARM_v1.0.9 中的 interface、src 和 test 文件夹拷贝到项目模块 xxx/src/main/cpp/silk/ 文件夹下

3、模块 build.gradle 文件 android 项下的 defaultConfig 项添加以下内容

android {
...
    defaultConfig {
    ...
        externalNativeBuild {
            cmake {
                cppFlags "-std=c++11 -frtti -fexceptions"
                // 要支持 'armeabi-v7a' 需开启 NO_ASM 宏
                cFlags "-DNO_ASM"
            }
        }
    }
...
}

4、模块 build.gradle 文件的 android 项添加以下内容

android {
...
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

5、模块顶级文件夹下新增 CMakeLists.txt 文件，内容如下:

# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html

# Sets the minimum version of CMake required to build the native library.

cmake_minimum_required(VERSION 3.4.1)

include_directories(src/main/cpp/silk/interface)
include_directories(src/main/cpp/silk/src)

aux_source_directory(src/main/cpp/silk/src SILK_SRC)

add_executable(decoder src/main/cpp/silk/test/Decoder.c ${SILK_SRC})
add_executable(encoder src/main/cpp/silk/test/Encoder.c ${SILK_SRC})
add_executable(signalcompare src/main/cpp/silk/test/signalCompare.c ${SILK_SRC})

6、编译模块

       编译成功后，将在 xxx/build/intermediates/cmake/debug/obj/arm64-v8a 路径下生成 3 个文件：decoder、encoder 和 signalcompare

测试

1、在手机上创建测试文件夹

adb shell "mkdir /data/local/tmp/silk/"

2、将生成的可执行文件推到手机

cd xxx/build/intermediates/cmake/debug/obj/arm64-v8a/
adb push decoder /data/local/tmp/silk/
adb push encoder /data/local/tmp/silk/
adb push signalcompare /data/local/tmp/silk/

3、将 silk 源码自带的测试文件夹推到手机

cd xxx/SILK_SDK_SRC_ARM_v1.0.9/
adb push test_vectors /data/local/tmp/silk/

4、添加执行权限

adb shell "chmod 777 -R /data/local/tmp/silk/"

5、执行解码测试脚本

adb shell
cd /data/local/tmp/silk/test_vectors/
bash test_decoder.sh

       执行完会在当前路径生成 test_decoder_report.txt 文件，其内容如下：

Reference:  ./test_vectors/output/testvector_output_8_kHz_60_ms_8_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_8_kHz_60_ms_8_kbps_8_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_8_kHz_60_ms_8_kbps_12_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_8_kHz_60_ms_8_kbps_16_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_8_kHz_40_ms_12_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_8_kHz_20_ms_20_kbps_10_loss_FEC.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_60_ms_10_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_60_ms_10_kbps_12_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_60_ms_10_kbps_16_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_60_ms_10_kbps_32_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_60_ms_10_kbps_44100_Hz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_60_ms_10_kbps_48_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_40_ms_16_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_12_kHz_20_ms_24_kbps_10_loss_FEC.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_16_kHz_60_ms_12_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_16_kHz_60_ms_12_kbps_16_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_16_kHz_40_ms_20_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_16_kHz_20_ms_32_kbps_10_loss_FEC.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_24_kHz_60_ms_16_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_24_kHz_40_ms_24_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_24_kHz_20_ms_40_kbps_10_loss_FEC.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_32_kHz_max_8_kHz_20_ms_8_kbps.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_32_kHz_max_8_kHz_20_ms_8_kbps_32_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_32_kHz_max_8_kHz_20_ms_8_kbps_44100_Hz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_32_kHz_max_8_kHz_20_ms_8_kbps_48_kHz_out.pcm
Signals are bit-exact          PASS

Reference:  ./test_vectors/output/testvector_output_44100_Hz_20_ms_7_kbps.pcm
Signals are bit-exact          PASS

6、执行编码测试脚本

adb shell
cd /data/local/tmp/silk/test_vectors/
bash test_encoder.sh

       执行完会在当前路径生成 test_encoder_report.txt 文件，其内容如下：

Reference:  ./test_vectors/bitstream/payload_8_kHz_60_ms_8_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_8_kHz_40_ms_12_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_8_kHz_20_ms_20_kbps_10_loss_FEC.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_12_kHz_60_ms_10_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_12_kHz_40_ms_16_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_12_kHz_20_ms_24_kbps_10_loss_FEC.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_16_kHz_60_ms_12_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_16_kHz_40_ms_20_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_16_kHz_20_ms_32_kbps_10_loss_FEC.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_24_kHz_60_ms_16_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_24_kHz_40_ms_24_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_24_kHz_20_ms_40_kbps_10_loss_FEC.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_32_kHz_max_8_kHz_20_ms_8_kbps.bit
Signals are bit-exact          PASS

Reference:  ./test_vectors/bitstream/payload_44100_Hz_20_ms_7_kbps.bit
Signals are bit-exact          PASS

参考文章

Silk编解码在android实现

CMakeLists File