Great question! Since you're working with a headless Linux server using raw ALSA for audio playback and want to redirect output to your Windows machine via MobaXTerm SSH, here are two practical approaches that let you avoid modifying your core playback code (only adjusting the ALSA output device is needed):

Approach 1: Use MobaXTerm's Built-in PulseAudio Forwarding (Simplest) #

MobaXTerm has native support for PulseAudio audio forwarding, which integrates seamlessly with ALSA via a plugin. This is the easiest method since it requires minimal setup:

1. Install PulseAudio & ALSA Plugin on Linux
   On Debian/Ubuntu-based systems, run:

   sudo apt update && sudo apt install pulseaudio alsa-utils pulseaudio-utils
   

   For RHEL/CentOS/Fedora, use:

   sudo dnf install pulseaudio alsa-utils pulseaudio-libs
   

2. Configure ALSA to Use PulseAudio by Default
   Create or edit the user-specific ALSA config file ~/.asoundrc with this content (this makes PulseAudio your default ALSA device, so your existing code doesn't need changes):

   pcm.!default {
       type pulse
   }
   ctl.!default {
       type pulse
   }
   

   If you want system-wide configuration, edit /etc/asound.conf instead.

3. Enable PulseAudio Forwarding in MobaXTerm

   • Open MobaXTerm, go to Settings > Configuration > SSH
   • Check the box labeled Enable PulseAudio forwarding (this is usually enabled by default, but double-check)

4. Test & Run Your Program
   Connect to your Linux server via SSH in MobaXTerm. Now run your ALSA program—if you're using the default device in snd_pcm_open, it will automatically route audio through the SSH tunnel to your Windows speakers. You can test with a sample audio file first:

   aplay /usr/share/sounds/alsa/Front_Center.wav
   

Approach 2: ALSA TCP Plugin + SSH Port Forwarding (No PulseAudio Needed) #

If you prefer not to use PulseAudio, you can set up an ALSA TCP output device and forward the port via SSH to a Windows audio player like ffplay (included with FFmpeg, which you can install on Windows easily):

1. Configure ALSA TCP Output on Linux
   Add this to your ~/.asoundrc file (adjust the audio format parameters to match your program's settings—SND_PCM_FORMAT_S32, your sample rate, and channel count):

   pcm.tcp_audio {
       type tcp
       slave {
           pcm {
               type raw
               format S32_LE
               rate 44100  # Replace with your program's sampleRate
               channels 2  # Replace with your program's width (channel count)
           }
       }
       server 127.0.0.1
       port 4567
   }
   

2. Set Up SSH Port Forwarding in MobaXTerm

   • When creating/editing your SSH session in MobaXTerm, go to the Advanced SSH settings tab
   • Under Port forwarding, add a new rule:
     • Type: Local
     • Forwarded port: 4567
     • Remote server: 127.0.0.1
     • Remote port: 4567
       This forwards traffic from your Windows machine's localhost:4567 to the server's localhost:4567.

3. Run Audio Receiver on Windows
   Install FFmpeg on Windows, then open a Command Prompt/PowerShell and run:

   ffplay -f s32le -ar 44100 -ac 2 tcp://localhost:4567
   

   Adjust the parameters (-ar for sample rate, -ac for channels) to match your ALSA program's configuration.

4. Update Your Program's Output Device
   Modify the device parameter in snd_pcm_open to use tcp_audio instead of your local speaker device:

   snd_pcm_open(&handle, "tcp_audio", SND_PCM_STREAM_PLAYBACK, 0);
   

   No other code changes are needed—your program will send audio over the SSH tunnel to the Windows FFplay instance.

内容的提问来源于stack exchange，提问作者ZioByte