Embedded Linux (arm)

This page describes how to build sherpa-onnx for embedded Linux (arm, 32-bit) with cross-compiling on an x86 machine with Ubuntu OS.

Caution

If you want to build sherpa-onnx directly on your board, please don’t use this document. Refer to Linux instead.

Caution

If you want to build sherpa-onnx directly on your board, please don’t use this document. Refer to Linux instead.

Caution

If you want to build sherpa-onnx directly on your board, please don’t use this document. Refer to Linux instead.

Hint

This page is for cross-compiling.

Note

You can download pre-compiled binaries for 32-bit ARM from the following URL https://huggingface.co/csukuangfj/sherpa-onnx-libs/tree/main/arm32

Please always download the latest version.

Example command to download the version 1.9.12:

# binaries built with shared libraries
wget https://huggingface.co/csukuangfj/sherpa-onnx-libs/resolve/main/arm32/sherpa-onnx-v1.9.12-linux-arm-gnueabihf-shared.tar.bz2

# binaries built with static link
wget https://huggingface.co/csukuangfj/sherpa-onnx-libs/resolve/main/arm32/sherpa-onnx-v1.9.12-linux-arm-gnueabihf-static.tar.bz2

# For users from China
# 中国国内用户，如果访问不了 huggingface, 请使用

# binaries built with shared libraries
wget https://hf-mirror.com/csukuangfj/sherpa-onnx-libs/resolve/main/arm32/sherpa-onnx-v1.9.12-linux-arm-gnueabihf-shared.tar.bz2

# binaries built with static link
wget https://hf-mirror.com/csukuangfj/sherpa-onnx-libs/resolve/main/arm32/sherpa-onnx-v1.9.12-linux-arm-gnueabihf-static.tar.bz2

Hint

We provide two colab notebooks for you to try this section step by step.

Build with shared libraries

Build with static libraries

build sherpa-onnx for arm shared colab notebook

build sherpa-onnx for arm static colab notebook

If you are using Windows/macOS or you don’t want to setup your local environment for cross-compiling, please use the above colab notebooks.

Install toolchain

The first step is to install a toolchain for cross-compiling.

Warning

You can use any toolchain that is suitable for your platform. The toolchain we use below is just an example.

Visit https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads to download the toolchain:

We are going to download gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz, which has been uploaded to https://huggingface.co/csukuangfj/sherpa-ncnn-toolchains.

Assume you want to install it in the folder $HOME/software:

mkdir -p $HOME/software
cd $HOME/software
wget -q https://huggingface.co/csukuangfj/sherpa-ncnn-toolchains/resolve/main/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz

# For users from China
# 中国国内用户，如果访问不了 huggingface, 请使用
# wget -q https://hf-mirror.com/csukuangfj/sherpa-ncnn-toolchains/resolve/main/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz

tar xf gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz

Next, we need to set the following environment variable:

export PATH=$HOME/software/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf/bin:$PATH

To check that we have installed the cross-compiling toolchain successfully, please run:

arm-none-linux-gnueabihf-gcc --version

which should print the following log:

arm-none-linux-gnueabihf-gcc (GNU Toolchain for the A-profile Architecture 10.3-2021.07 (arm-10.29)) 10.3.1 20210621
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Congratulations! You have successfully installed a toolchain for cross-compiling sherpa-onnx.

Build sherpa-onnx

Finally, let us build sherpa-onnx.

git clone https://github.com/k2-fsa/sherpa-onnx
cd sherpa-onnx
export BUILD_SHARED_LIBS=ON
./build-arm-linux-gnueabihf.sh

After building, you will get the following binaries:

$ ls -lh  build-arm-linux-gnueabihf/install/bin/

total 1.2M
-rwxr-xr-x 1 kuangfangjun root 395K Jul  7 16:28 sherpa-onnx
-rwxr-xr-x 1 kuangfangjun root 391K Jul  7 16:28 sherpa-onnx-alsa
-rwxr-xr-x 1 kuangfangjun root 351K Jul  7 16:28 sherpa-onnx-offline

That’s it!

Hint

  • sherpa-onnx is for decoding a single file using a streaming model

  • sherpa-onnx-offline is for decoding a single file using a non-streaming model

  • sherpa-onnx-alsa is for real-time speech recongition using a streaming model by reading the microphone with ALSA

Caution

We recommend that you use sherpa-onnx-alsa on embedded systems such as Raspberry pi.

You need to provide a device_name when invoking sherpa-onnx-alsa. We describe below how to find the device name for your microphone.

Run the following command:

arecord -l

to list all avaliable microphones for recording. If it complains that arecord: command not found, please use sudo apt-get install alsa-utils to install it.

If the above command gives the following output:

**** List of CAPTURE Hardware Devices ****
card 0: Audio [Axera Audio], device 0: 49ac000.i2s_mst-es8328-hifi-analog es8328-hifi-analog-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

In this case, I only have 1 microphone. It is card 0 and that card has only device 0. To select card 0 and device 0 on that card, we need to pass plughw:0,0 to sherpa-onnx-alsa. (Note: It has the format plughw:card_number,device_index.)

For instance, you have to use

# Note: We use int8 models below.
./bin/sherpa-onnx-alsa \
  ./sherpa-onnx-streaming-zipformer-en-2023-06-26/tokens.txt \
  ./sherpa-onnx-streaming-zipformer-en-2023-06-26/encoder-epoch-99-avg-1-chunk-16-left-64.int8.onnx \
  ./sherpa-onnx-streaming-zipformer-en-2023-06-26/decoder-epoch-99-avg-1-chunk-16-left-64.int8.onnx \
  ./sherpa-onnx-streaming-zipformer-en-2023-06-26/joiner-epoch-99-avg-1-chunk-16-left-64.int8.onnx \
  "plughw:0,0"

Please change the card number and also the device index on the selected card accordingly in your own situation. Otherwise, you won’t be able to record with your microphone.

Please read Pre-trained models for usages about the generated binaries.

Read below if you want to learn more.

Hint

By default, all external dependencies are statically linked. That means, the generated binaries are self-contained (except that it requires the onnxruntime shared library at runtime).

You can use the following commands to check that and you will find they depend only on system libraries.

$ readelf -d build-arm-linux-gnueabihf/install/bin/sherpa-onnx

  Dynamic section at offset 0x61ee8 contains 30 entries:
    Tag        Type                         Name/Value
   0x00000001 (NEEDED)                     Shared library: [libonnxruntime.so.1.14.0]
   0x00000001 (NEEDED)                     Shared library: [libstdc++.so.6]
   0x00000001 (NEEDED)                     Shared library: [libm.so.6]
   0x00000001 (NEEDED)                     Shared library: [libgcc_s.so.1]
   0x00000001 (NEEDED)                     Shared library: [libc.so.6]
   0x0000000f (RPATH)                      Library rpath: [$ORIGIN:$ORIGIN/../lib:$ORIGIN/../../../sherpa_onnx/lib]

$ readelf -d build-arm-linux-gnueabihf/install/bin/sherpa-onnx-alsa

  Dynamic section at offset 0x60ee0 contains 31 entries:
    Tag        Type                         Name/Value
   0x00000001 (NEEDED)                     Shared library: [libasound.so.2]
   0x00000001 (NEEDED)                     Shared library: [libonnxruntime.so.1.14.0]
   0x00000001 (NEEDED)                     Shared library: [libstdc++.so.6]
   0x00000001 (NEEDED)                     Shared library: [libm.so.6]
   0x00000001 (NEEDED)                     Shared library: [libgcc_s.so.1]
   0x00000001 (NEEDED)                     Shared library: [libc.so.6]
   0x0000000f (RPATH)                      Library rpath: [$ORIGIN]

Please create an issue at https://github.com/k2-fsa/sherpa-onnx/issues if you have any problems.

How to build static libraries and static linked binaries

If you want to build static libraries and static linked binaries, please first download a cross compile toolchain with GCC >= 9.0. The following is an example:

mkdir -p $HOME/software
cd $HOME/software
wget -q https://huggingface.co/csukuangfj/sherpa-ncnn-toolchains/resolve/main/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz

# For users from China
# 中国国内用户，如果访问不了 huggingface, 请使用
wget -q https://hf-mirror.com/csukuangfj/sherpa-ncnn-toolchains/resolve/main/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz

tar xf gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz

Next, we need to set the following environment variable:

export PATH=$HOME/software/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf/bin:$PATH

To check that we have installed the cross-compiling toolchain successfully, please run:

arm-none-linux-gnueabihf-gcc --version

which should print the following log:

arm-none-linux-gnueabihf-gcc (GNU Toolchain for the A-profile Architecture 10.3-2021.07 (arm-10.29)) 10.3.1 20210621
Copyright (C) 2020 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Now you can build static libraries and static linked binaries with the following commands:

git clone https://github.com/k2-fsa/sherpa-onnx
cd sherpa-onnx
export BUILD_SHARED_LIBS=OFF
./build-arm-linux-gnueabihf.sh

You can use the following commands to check that the generated binaries are indeed static linked:

$ cd build-arm-linux-gnueabihf/bin

$ ldd sherpa-onnx-alsa
    not a dynamic executable

$ readelf -d sherpa-onnx-alsa

Dynamic section at offset 0xa68eb4 contains 31 entries:
  Tag        Type                         Name/Value
 0x00000001 (NEEDED)                     Shared library: [libasound.so.2]
 0x00000001 (NEEDED)                     Shared library: [libdl.so.2]
 0x00000001 (NEEDED)                     Shared library: [libm.so.6]
 0x00000001 (NEEDED)                     Shared library: [libpthread.so.0]
 0x00000001 (NEEDED)                     Shared library: [libc.so.6]
 0x00000001 (NEEDED)                     Shared library: [ld-linux-armhf.so.3]
 0x0000000f (RPATH)                      Library rpath: [$ORIGIN:/star-fj/fangjun/open-source/sherpa-onnx/build-arm-linux-gnueabihf/_deps/espeak_ng-src/lib:/star-fj/fangjun/open-source/sherpa-onnx/build-arm-linux-gnueabihf/_deps/onnxruntime-src/lib:]
 0x0000000c (INIT)                       0x13550