Why does piper hang when piping input text is not used?

[guest271314]

This hangs

 /home/user/.local/bin/piper --length_scale 1 --sentence_silence 0  --model ~/.local/share/piper/voices/en_US-hfc_female-medium.onnx -f ~/bin/test.wav "test"
[2024-08-11 09:00:21.634] [piper] [info] Loaded voice in 0.764360843 second(s)
[2024-08-11 09:00:21.635] [piper] [info] Initialized piper
^C

This doesn't hang

echo "test" | /home/user/.local/bin/piper --length_scale 1 --sentence_silence 0  --model ~/.local/share/piper/voices/en_US-hfc_female-medium.onnx -f ~/bin/test.wav
[2024-08-11 08:59:03.009] [piper] [info] Loaded voice in 0.751065798 second(s)
[2024-08-11 08:59:03.010] [piper] [info] Initialized piper
/home/xubuntu/bin/test.wav
[2024-08-11 08:59:03.302] [piper] [info] Real-time factor: 0.5466238986461291 (infer=0.279236807 sec, audio=0.5108390022675737 sec)
[2024-08-11 08:59:03.302] [piper] [info] Terminated piper

[synesthesiam]

It's not hanging, it's waiting for text.
Type some in and hit enter (CTRL+D to end).

[guest271314]

Why is the program made that way? I'm not at a TTY. I'm passing input through another program. We should be able to do piper ... text and get the output directly.

[guest271314]

@synesthesiam What I'm thinking about is the different engines or runtimes or programs that I might launch piper from as a subprocess, some of which could expect something like os.system(command, [arg0, args1, arg2]). How would we write echo "test" | piper ... in such a case?

I would probably find a way around that, yet I don't think I have encountered a program that exclusively expects input to be echoed.

[guest271314]

@synesthesiam An example of the case of executing piper as a subprocess with Deno.command() https://docs.deno.com/api/deno/~/Deno.Command. I'm not seeing a way we can use echo "test" | piper <args>

const command = new Deno.Command("/home/user/.local/opt/piper/piper", {
  args: [
    "-q", 
    "--length_scale", 
    "1", 
    "--sentence_silence", 
    "0",
    "--model",
    "./en_US-hfc_${Deno.args[0]}-medium.onnx",
    " --output-raw"
  ],
  stdout: "piped",
  stdin: "piped",
});
const process = command.spawn();
await process.stdout.pipeTo(Deno.stdout.writable);

We can do this using dax https://github.com/dsherret/dax, which is a shell for Deno

import $ from "./dax.js";

try {
  await $`echo ${Deno.args[1]} | $HOME/.local/opt/piper/piper -q
  --length_scale 1
  --sentence_silence 0
  --model ./en_US-hfc_${Deno.args[0]}-medium.onnx --output-raw`
    .stdout(Deno.stdout.writable);
} catch (e) {
  $.logError(e.message);
  $`exit(1)`;
}

An option for piper to expect the text or to just use the text when --json-input is used would be helpful for this case.

[guest271314]

I guess there is a way to do this using bash -c

const command = new Deno.Command("bash", {
  args: [
    "--posix", 
    "-c", 
    `echo ${Deno.args[1]} | $HOME/.local/opt/piper/piper -q --length_scale 1 --sentence_silence 0 --model $HOME/vits-web-extension/en_US-hfc_${Deno.args[0]}-medium.onnx --output-raw -`
  ],
  stdout: "piped",
  stdin: "piped",
});
const process = command.spawn();
await process.stdout.pipeTo(Deno.stdout.writable);