From ad5d954edb2af59d3c73d00a6b9fcfd392168288 Mon Sep 17 00:00:00 2001
From: Muaz Ahmad <mahmad2000@protonmail.com>
Date: Mon, 9 Oct 2023 15:28:42 +0500
Subject: [PATCH] basic placeholders for codecs H264 and AAC

---
 src/decode/cmds.rs         | 11 ++++++++++-
 src/decode/codecs/audio.rs | 36 ++++++++++++++++++++++++++++++++++++
 src/decode/codecs/mod.rs   |  3 +++
 src/decode/codecs/video.rs | 36 ++++++++++++++++++++++++++++++++++++
 src/decode/mod.rs          |  8 --------
 src/util/mod.rs            | 24 ++++++++++++++++++++++++
 6 files changed, 109 insertions(+), 9 deletions(-)
 create mode 100644 src/decode/codecs/audio.rs
 create mode 100644 src/decode/codecs/video.rs

diff --git a/src/decode/cmds.rs b/src/decode/cmds.rs
index 082013e..e851ce1 100644
--- a/src/decode/cmds.rs
+++ b/src/decode/cmds.rs
@@ -3,7 +3,16 @@ use std::error::Error;
 
 use crate::util;
 use crate::decode::codecs::Decoder;
+use crate::decode::codecs;
 
 pub fn spawn(metadata: Arc<util::Metadata>) -> Result<(impl Decoder, impl Decoder), Box<dyn Error>> {
-    todo!();
+    let v = match metadata.video.codec {
+        Some(util::VideoCodec::H264) => codecs::video::new_h264(metadata.clone())?,
+        _ => {return Err(Box::new(util::DecoderError::CodecNotImplemented));}
+    };
+    let a = match metadata.audio.codec {
+        Some(util::AudioCodec::AAC) => codecs::audio::new_aac(metadata)?,
+        _ => {return Err(Box::new(util::DecoderError::CodecNotImplemented));}
+    };
+    return Ok((v, a));
 }
diff --git a/src/decode/codecs/audio.rs b/src/decode/codecs/audio.rs
new file mode 100644
index 0000000..877cf23
--- /dev/null
+++ b/src/decode/codecs/audio.rs
@@ -0,0 +1,36 @@
+use std::error::Error;
+use std::process::{ChildStdin, ChildStdout, Command, Stdio};
+use std::sync::Arc;
+use std::io::{Read, Write};
+
+use crate::decode::codecs::Decoder;
+use crate::util;
+
+pub struct AACDecoder {
+    stdin: ChildStdin,
+    stdout: ChildStdout,
+    metadata: Arc<util::Metadata>,
+}
+
+impl Decoder for AACDecoder {
+    fn write_nalu(&mut self, nalu: util::NALUPacket) -> Result<(), Box<dyn Error + Send + Sync>> {
+        self.stdin.write_all(nalu.packet_data.as_slice())?;
+        Ok(())
+    }
+    fn read_raw(&mut self) -> Result<util::RawMedia, Box<dyn Error + Send + Sync>> {
+        todo!();
+    }
+}
+
+pub fn new_aac(metadata: Arc<util::Metadata>) -> Result<AACDecoder, Box<dyn Error>> {
+    let cmd = Command::new("tee").stdin(Stdio::piped()).stdout(Stdio::piped()).spawn()?;
+    let stdin = match cmd.stdin {
+        Some(x) => x,
+        None => {return Err(Box::new(util::DecoderError::InvalidPipeInit))}
+    };
+    let stdout = match cmd.stdout {
+        Some(x) => x,
+        None => {return Err(Box::new(util::DecoderError::InvalidPipeInit))}
+    };
+    return Ok(AACDecoder {stdin: stdin, stdout: stdout, metadata: metadata})
+}
diff --git a/src/decode/codecs/mod.rs b/src/decode/codecs/mod.rs
index 31f3302..8d28350 100644
--- a/src/decode/codecs/mod.rs
+++ b/src/decode/codecs/mod.rs
@@ -1,3 +1,6 @@
+pub mod video;
+pub mod audio;
+
 use std::sync::mpsc;
 use std::error::Error;
 
diff --git a/src/decode/codecs/video.rs b/src/decode/codecs/video.rs
new file mode 100644
index 0000000..b26c929
--- /dev/null
+++ b/src/decode/codecs/video.rs
@@ -0,0 +1,36 @@
+use std::error::Error;
+use std::process::{ChildStdin, ChildStdout, Stdio, Command};
+use std::sync::Arc;
+use std::io::{Read, Write};
+
+use crate::decode::codecs::Decoder;
+use crate::util;
+
+pub struct H264Decoder {
+    stdin: ChildStdin,
+    stdout: ChildStdout,
+    metadata: Arc<util::Metadata>,
+}
+
+impl Decoder for H264Decoder {
+    fn write_nalu(&mut self, nalu: util::NALUPacket) -> Result<(), Box<dyn Error + Send + Sync>> {
+        self.stdin.write_all(nalu.packet_data.as_slice())?;
+        Ok(())
+    }
+    fn read_raw(&mut self) -> Result<util::RawMedia, Box<dyn Error + Send + Sync>> {
+        todo!();
+    }
+}
+
+pub fn new_h264(metadata: Arc<util::Metadata>) -> Result<H264Decoder, Box<dyn Error>> {
+    let cmd = Command::new("tee").stdin(Stdio::piped()).stdout(Stdio::piped()).spawn()?;
+    let stdin = match cmd.stdin {
+        Some(x) => x,
+        None => {return Err(Box::new(util::DecoderError::InvalidPipeInit))}
+    };
+    let stdout = match cmd.stdout {
+        Some(x) => x,
+        None => {return Err(Box::new(util::DecoderError::InvalidPipeInit))}
+    };
+    return Ok(H264Decoder {stdin: stdin, stdout: stdout, metadata: metadata});
+}
diff --git a/src/decode/mod.rs b/src/decode/mod.rs
index acc0d44..1b92f8c 100644
--- a/src/decode/mod.rs
+++ b/src/decode/mod.rs
@@ -25,14 +25,6 @@ pub fn spawn(
     let (err_in, err_out) = mpsc::channel();
     let (v_decoder, a_decoder) = cmds::spawn(metadata.clone())?;
     spawn_threads(v, raw_v_in, v_decoder, a, raw_a_in, a_decoder, err_in);
-    thread::spawn(move || {
-        &raw_v_in;
-        &raw_a_in;
-        &err_in;
-        &v;
-        &a;
-        thread::park();
-    });
     return Ok((raw_v_out, raw_a_out, err_out));
 }
 
diff --git a/src/util/mod.rs b/src/util/mod.rs
index cb92b51..35133ba 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -128,6 +128,30 @@ impl fmt::Display for DemuxerError {
     }
 }
 
+pub enum DecoderError {
+    CodecNotImplemented,
+    InvalidPipeInit,
+}
+
+impl Error for DecoderError {}
+
+#[allow(unreachable_patterns)]
+impl fmt::Debug for DecoderError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            DecoderError::CodecNotImplemented => write!(f, "Codec not recognized"),
+            DecoderError::InvalidPipeInit => write!(f, "Decoder has invalid piping"),
+            _ => write!(f, "Error not described yet")
+        }
+    }
+}
+
+impl fmt::Display for DecoderError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(self, f)
+    }
+}
+
 // funcs
 
 pub fn thread_freeze(err_sender: mpsc::Sender<Box<dyn Error + Send + Sync>>, err: Box<dyn Error + Send + Sync>) {