feat: custom io mux

src/demux.rs

@@ -72,14 +72,18 @@ impl Demuxer {
         crate::set_opts(self.ctx as *mut libc::c_void, options)
     }
 
-    unsafe fn open_input(&mut self) -> libc::c_int {
+    unsafe fn open(&mut self) -> Result<()> {
         match &mut self.input {
-            DemuxerInput::Url(input) => avformat_open_input(
+            DemuxerInput::Url(input) => {
+                let ret = avformat_open_input(
                     &mut self.ctx,
-                cstr!(input),
+                    cstr!(input.as_str()),
                     ptr::null_mut(),
                     ptr::null_mut(),
-            ),
+                );
+                bail_ffmpeg!(ret);
+                Ok(())
+            }
             DemuxerInput::Reader(input, url) => {
                 let input = input.take().expect("input stream already taken");
                 const BUFFER_SIZE: usize = 4096;
@@ -92,26 +96,29 @@ impl Demuxer {
                     None,
                     None,
                 );
+                if pb.is_null() {
+                    bail!("failed to allocate avio context");
+                }
 
                 (*self.ctx).pb = pb;
-                avformat_open_input(
+                let ret = avformat_open_input(
                     &mut self.ctx,
                     if let Some(url) = url {
-                        cstr!(url)
+                        cstr!(url.as_str())
                     } else {
                         ptr::null_mut()
                     },
                     ptr::null_mut(),
                     ptr::null_mut(),
-                )
+                );
+                bail_ffmpeg!(ret);
+                Ok(())
             }
         }
     }
 
     pub unsafe fn probe_input(&mut self) -> Result<DemuxerInfo, Error> {
-        let ret = self.open_input();
-        bail_ffmpeg!(ret);
-
+        self.open()?;
         if avformat_find_stream_info(self.ctx, ptr::null_mut()) < 0 {
             return Err(Error::msg("Could not find stream info"));
         }
@@ -237,7 +244,6 @@ impl Drop for Demuxer {
                     drop(SlimBox::<dyn Read>::from_raw((*(*self.ctx).pb).opaque));
                 }
                 avformat_free_context(self.ctx);
-                self.ctx = ptr::null_mut();
             }
         }
     }

src/lib.rs

@@ -11,7 +11,7 @@ mod decode;
 mod demux;
 mod encode;
 mod filter;
-mod muxer;
+mod mux;
 mod resample;
 mod scale;
 mod stream_info;
@@ -34,7 +34,7 @@ macro_rules! bail_ffmpeg {
 #[macro_export]
 macro_rules! cstr {
     ($str:expr) => {
-        format!("{}\0", $str).as_ptr() as *const libc::c_char
+        std::ffi::CString::new($str).unwrap().into_raw()
     };
 }
 
@@ -166,7 +166,7 @@ pub use demux::*;
 pub use encode::*;
 pub use ffmpeg_sys_the_third;
 pub use filter::*;
-pub use muxer::*;
+pub use mux::*;
 pub use resample::*;
 pub use scale::*;
 pub use stream_info::*;

src/mux.rs

@@ -0,0 +1,348 @@
+use crate::{bail_ffmpeg, cstr, set_opts, Encoder};
+use anyhow::{bail, Result};
+use ffmpeg_sys_the_third::{
+    av_dump_format, av_interleaved_write_frame, av_mallocz, av_packet_rescale_ts, av_write_trailer,
+    avcodec_parameters_copy, avcodec_parameters_from_context, avformat_alloc_output_context2,
+    avformat_free_context, avformat_new_stream, avformat_write_header, avio_alloc_context,
+    avio_open, AVFormatContext, AVPacket, AVStream, AVERROR_EOF, AVFMT_GLOBALHEADER, AVFMT_NOFILE,
+    AVIO_FLAG_WRITE, AV_CODEC_FLAG_GLOBAL_HEADER,
+};
+use slimbox::{slimbox_unsize, SlimBox, SlimMut};
+use std::collections::HashMap;
+use std::io::{Read, Seek, SeekFrom, Write};
+use std::{ptr, slice};
+
+#[no_mangle]
+unsafe extern "C" fn write_data(
+    opaque: *mut libc::c_void,
+    buffer: *const u8,
+    size: libc::c_int,
+) -> libc::c_int {
+    let mut writer: SlimMut<'_, dyn WriteSeek + 'static> = SlimMut::from_raw(opaque);
+    let data = slice::from_raw_parts(buffer, size as usize);
+    match writer.write_all(data) {
+        Ok(_) => size,
+        Err(e) => {
+            eprintln!("write_data {}", e);
+            AVERROR_EOF
+        }
+    }
+}
+
+#[no_mangle]
+unsafe extern "C" fn seek_data(opaque: *mut libc::c_void, offset: i64, whence: libc::c_int) -> i64 {
+    let mut writer: SlimMut<'_, dyn WriteSeek + 'static> = SlimMut::from_raw(opaque);
+    match whence {
+        libc::SEEK_SET => writer.seek(SeekFrom::Start(offset as u64)).unwrap_or(0) as i64,
+        libc::SEEK_CUR => writer.seek(SeekFrom::Current(offset)).unwrap_or(0) as i64,
+        libc::SEEK_END => writer.seek(SeekFrom::End(offset)).unwrap_or(0) as i64,
+        _ => panic!("seek_data not supported from whence {}", whence),
+    }
+}
+
+pub struct Muxer {
+    ctx: *mut AVFormatContext,
+    output: MuxerOutput,
+}
+
+pub trait WriteSeek: Seek + Write {}
+impl<T: Seek + Write> WriteSeek for T {}
+
+pub enum MuxerOutput {
+    Url(String),
+    Writer(Option<SlimBox<dyn WriteSeek + 'static>>),
+}
+
+impl Drop for Muxer {
+    fn drop(&mut self) {
+        unsafe {
+            if !self.ctx.is_null() {
+                if let MuxerOutput::Writer(_) = self.output {
+                    drop(SlimBox::<dyn Read>::from_raw((*(*self.ctx).pb).opaque));
+                }
+                avformat_free_context(self.ctx);
+            }
+        }
+    }
+}
+
+pub struct MuxerBuilder {
+    value: Muxer,
+}
+
+impl MuxerBuilder {
+    pub fn new() -> Self {
+        Self {
+            value: Muxer {
+                ctx: ptr::null_mut(),
+                output: MuxerOutput::Url(String::new()),
+            },
+        }
+    }
+
+    unsafe fn init_ctx(
+        &mut self,
+        dst: &str,
+        format: Option<&str>,
+        options: Option<HashMap<String, String>>,
+    ) -> Result<()> {
+        if !self.value.ctx.is_null() {
+            bail!("context already open");
+        }
+
+        let ret = avformat_alloc_output_context2(
+            &mut self.value.ctx,
+            ptr::null_mut(),
+            if let Some(format) = format {
+                cstr!(format)
+            } else {
+                ptr::null()
+            },
+            cstr!(dst),
+        );
+        bail_ffmpeg!(ret);
+
+        // Setup global header flag
+        if (*(*self.value.ctx).oformat).flags & AVFMT_GLOBALHEADER != 0 {
+            (*self.value.ctx).flags |= AV_CODEC_FLAG_GLOBAL_HEADER as libc::c_int;
+        }
+
+        // Set options on ctx
+        if let Some(opts) = options {
+            set_opts((*self.value.ctx).priv_data, opts)?;
+        }
+        Ok(())
+    }
+
+    /// Open the muxer with a destination path
+    pub unsafe fn with_output_path<'a, T>(
+        mut self,
+        dst: T,
+        format: Option<&'a str>,
+        options: Option<HashMap<String, String>>,
+    ) -> Result<Self>
+    where
+        T: Into<&'a str>,
+    {
+        let path_str = dst.into();
+        self.init_ctx(path_str, format, options)?;
+        self.value.output = MuxerOutput::Url(path_str.to_string());
+        Ok(self)
+    }
+
+    pub unsafe fn with_output_writer<'a, T, W>(
+        mut self,
+        writer: W,
+        dst: T,
+        format: Option<&'a str>,
+        options: Option<HashMap<String, String>>,
+    ) -> Result<Self>
+    where
+        T: Into<&'a str>,
+        W: WriteSeek + 'static,
+    {
+        self.init_ctx(dst.into(), format, options)?;
+        self.value.output = MuxerOutput::Writer(Some(slimbox_unsize!(writer)));
+        Ok(self)
+    }
+
+    /// Add a stream to the output using an existing encoder
+    pub unsafe fn with_stream_encoder(mut self, encoder: &Encoder) -> Result<Self> {
+        self.value.add_stream_encoder(encoder)?;
+        Ok(self)
+    }
+
+    /// Add a stream to the output using an existing input stream (copy)
+    pub unsafe fn with_copy_stream(mut self, in_stream: *mut AVStream) -> Result<Self> {
+        self.value.add_copy_stream(in_stream)?;
+        Ok(self)
+    }
+
+    /// Build the muxer
+    pub fn build(self) -> Result<Muxer> {
+        if self.value.ctx.is_null() {
+            bail!("context is null");
+        }
+        Ok(self.value)
+    }
+}
+
+impl Muxer {
+    pub fn builder() -> MuxerBuilder {
+        MuxerBuilder::new()
+    }
+
+    /// Add a stream to the output using an existing encoder
+    pub unsafe fn add_stream_encoder(&mut self, encoder: &Encoder) -> Result<*mut AVStream> {
+        let stream = avformat_new_stream(self.ctx, encoder.codec());
+        if stream.is_null() {
+            bail!("unable to allocate stream");
+        }
+        let ret = avcodec_parameters_from_context((*stream).codecpar, encoder.codec_context());
+        bail_ffmpeg!(ret);
+
+        // setup other stream params
+        let encoder_ctx = encoder.codec_context();
+        (*stream).time_base = (*encoder_ctx).time_base;
+        (*stream).avg_frame_rate = (*encoder_ctx).framerate;
+        (*stream).r_frame_rate = (*encoder_ctx).framerate;
+
+        Ok(stream)
+    }
+
+    /// Add a stream to the output using an existing input stream (copy)
+    pub unsafe fn add_copy_stream(&mut self, in_stream: *mut AVStream) -> Result<*mut AVStream> {
+        let stream = avformat_new_stream(self.ctx, ptr::null_mut());
+        if stream.is_null() {
+            bail!("unable to allocate stream");
+        }
+
+        // copy params from input
+        let ret = avcodec_parameters_copy((*stream).codecpar, (*in_stream).codecpar);
+        bail_ffmpeg!(ret);
+
+        Ok(stream)
+    }
+
+    /// Open the output to start sending packets
+    pub unsafe fn open(&mut self) -> Result<()> {
+        if (*(*self.ctx).oformat).flags & AVFMT_NOFILE == 0 {
+            if let MuxerOutput::Writer(w) = &mut self.output {
+                let writer = w.take().expect("writer already consumed");
+                const BUFFER_SIZE: usize = 1024;
+                let pb = avio_alloc_context(
+                    av_mallocz(BUFFER_SIZE) as *mut _,
+                    BUFFER_SIZE as _,
+                    1,
+                    writer.into_raw(),
+                    None,
+                    Some(write_data),
+                    Some(seek_data),
+                );
+                if pb.is_null() {
+                    bail!("failed to allocate avio context");
+                }
+                (*self.ctx).pb = pb;
+            } else {
+                let ret = avio_open(&mut (*self.ctx).pb, (*self.ctx).url, AVIO_FLAG_WRITE);
+                bail_ffmpeg!(ret);
+            }
+        }
+
+        let ret = avformat_write_header(self.ctx, ptr::null_mut());
+        bail_ffmpeg!(ret);
+
+        av_dump_format(self.ctx, 0, (*self.ctx).url, 1);
+
+        Ok(())
+    }
+
+    /// Write a packet to the output
+    pub unsafe fn write_packet(&mut self, pkt: *mut AVPacket) -> Result<()> {
+        let stream = *(*self.ctx).streams.add((*pkt).stream_index as usize);
+        av_packet_rescale_ts(pkt, (*pkt).time_base, (*stream).time_base);
+        (*pkt).time_base = (*stream).time_base;
+
+        let ret = av_interleaved_write_frame(self.ctx, pkt);
+        bail_ffmpeg!(ret);
+        Ok(())
+    }
+
+    /// Close the output and write the trailer
+    pub unsafe fn close(self) -> Result<()> {
+        let ret = av_write_trailer(self.ctx);
+        bail_ffmpeg!(ret);
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{generate_test_frame, Scaler};
+    use ffmpeg_sys_the_third::AVCodecID::AV_CODEC_ID_H264;
+    use ffmpeg_sys_the_third::AVPixelFormat::AV_PIX_FMT_YUV420P;
+    use ffmpeg_sys_the_third::{AVFrame, AV_PROFILE_H264_MAIN};
+
+    unsafe fn setup_encoder() -> Result<(*mut AVFrame, Encoder)> {
+        std::fs::create_dir_all("test_output")?;
+        let path = PathBuf::from("test_output/test.mp4");
+        let frame = generate_test_frame();
+
+        // convert frame to YUV
+        let mut scaler = Scaler::new();
+        let frame = scaler.process_frame(
+            frame,
+            (*frame).width as u16,
+            (*frame).height as u16,
+            AV_PIX_FMT_YUV420P,
+        )?;
+
+        let mut encoder = Encoder::new(AV_CODEC_ID_H264)?
+            .with_width((*frame).width)
+            .with_height((*frame).height)
+            .with_pix_fmt(AV_PIX_FMT_YUV420P)
+            .with_bitrate(1_000_000)
+            .with_framerate(30.0)
+            .with_profile(AV_PROFILE_H264_MAIN)
+            .with_level(50)
+            .open(None)?;
+        Ok((frame, encoder))
+    }
+
+    unsafe fn write_frames(
+        mut muxer: Muxer,
+        mut encoder: Encoder,
+        frame: *mut AVFrame,
+    ) -> Result<()> {
+        let mut pts = 0;
+        for _z in 0..100 {
+            (*frame).pts = pts;
+            for pkt in encoder.encode_frame(frame)? {
+                muxer.write_packet(pkt)?;
+            }
+            pts += 1;
+        }
+        // flush
+        for f_pk in encoder.encode_frame(ptr::null_mut())? {
+            muxer.write_packet(f_pk)?;
+        }
+        muxer.close()?;
+        Ok(())
+    }
+
+    #[test]
+    fn encode_mkv() -> Result<()> {
+        std::fs::create_dir_all("test_output")?;
+        unsafe {
+            let path = PathBuf::from("test_output/test_muxer.mp4");
+            let (frame, encoder) = setup_encoder()?;
+
+            let mut muxer = Muxer::builder()
+                .with_output_path(path.to_str().unwrap(), None, None)?
+                .with_stream_encoder(&encoder)?
+                .build()?;
+            muxer.open()?;
+            write_frames(muxer, encoder, frame)?;
+        }
+        Ok(())
+    }
+
+    #[test]
+    fn encode_custom_io() -> Result<()> {
+        std::fs::create_dir_all("test_output")?;
+        unsafe {
+            let path = PathBuf::from("test_output/test_custom_muxer.mp4");
+            let (frame, encoder) = setup_encoder()?;
+
+            let fout = std::fs::File::create(path)?;
+            let mut muxer = Muxer::builder()
+                .with_output_writer(fout, "custom.mp4", None, None)?
+                .with_stream_encoder(&encoder)?
+                .build()?;
+            muxer.open()?;
+            write_frames(muxer, encoder, frame)?;
+        }
+        Ok(())
+    }
+}

src/muxer.rs

@@ -1,203 +0,0 @@
-use crate::{bail_ffmpeg, cstr, set_opts, Encoder};
-use anyhow::{bail, Result};
-use ffmpeg_sys_the_third::{
-    av_dump_format, av_interleaved_write_frame, av_packet_rescale_ts, av_write_trailer,
-    avcodec_parameters_copy, avcodec_parameters_from_context, avformat_alloc_output_context2,
-    avformat_free_context, avformat_new_stream, avformat_write_header, avio_open, AVFormatContext,
-    AVPacket, AVStream, AVFMT_GLOBALHEADER, AVFMT_NOFILE, AVIO_FLAG_WRITE,
-    AV_CODEC_FLAG_GLOBAL_HEADER,
-};
-use std::collections::HashMap;
-use std::path::PathBuf;
-use std::ptr;
-
-pub struct Muxer {
-    ctx: *mut AVFormatContext,
-}
-
-impl Drop for Muxer {
-    fn drop(&mut self) {
-        unsafe {
-            if !self.ctx.is_null() {
-                avformat_free_context(self.ctx);
-            }
-        }
-    }
-}
-
-impl Default for Muxer {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl Muxer {
-    pub fn new() -> Self {
-        Self {
-            ctx: ptr::null_mut(),
-        }
-    }
-
-    /// Open the muxer with a destination path
-    pub unsafe fn with_output(
-        mut self,
-        dst: &PathBuf,
-        format: Option<&str>,
-        options: Option<HashMap<String, String>>,
-    ) -> Result<Self> {
-        if !self.ctx.is_null() {
-            bail!("context already open");
-        }
-
-        let ret = avformat_alloc_output_context2(
-            &mut self.ctx,
-            ptr::null_mut(),
-            if let Some(ref format) = format {
-                cstr!(format)
-            } else {
-                ptr::null()
-            },
-            cstr!(dst.to_str().unwrap()),
-        );
-        bail_ffmpeg!(ret);
-
-        // Setup global header flag
-        if (*(*self.ctx).oformat).flags & AVFMT_GLOBALHEADER != 0 {
-            (*self.ctx).flags |= AV_CODEC_FLAG_GLOBAL_HEADER as libc::c_int;
-        }
-
-        // Set options on ctx
-        if let Some(opts) = options {
-            set_opts((*self.ctx).priv_data, opts)?;
-        }
-
-        Ok(self)
-    }
-
-    /// Add a stream to the output using an existing encoder
-    pub unsafe fn with_stream_encoder(mut self, encoder: &Encoder) -> Result<Self> {
-        self.add_stream_encoder(encoder)?;
-        Ok(self)
-    }
-
-    /// Add a stream to the output using an existing encoder
-    pub unsafe fn add_stream_encoder(&mut self, encoder: &Encoder) -> Result<*mut AVStream> {
-        let stream = avformat_new_stream(self.ctx, encoder.codec());
-        if stream.is_null() {
-            bail!("unable to allocate stream");
-        }
-        let ret = avcodec_parameters_from_context((*stream).codecpar, encoder.codec_context());
-        bail_ffmpeg!(ret);
-
-        // setup other stream params
-        let encoder_ctx = encoder.codec_context();
-        (*stream).time_base = (*encoder_ctx).time_base;
-        (*stream).avg_frame_rate = (*encoder_ctx).framerate;
-        (*stream).r_frame_rate = (*encoder_ctx).framerate;
-
-        Ok(stream)
-    }
-
-    /// Add a stream to the output using an existing input stream (copy)
-    pub unsafe fn add_copy_stream(&mut self, in_stream: *mut AVStream) -> Result<*mut AVStream> {
-        let stream = avformat_new_stream(self.ctx, ptr::null_mut());
-        if stream.is_null() {
-            bail!("unable to allocate stream");
-        }
-
-        // copy params from input
-        let ret = avcodec_parameters_copy((*stream).codecpar, (*in_stream).codecpar);
-        bail_ffmpeg!(ret);
-
-        Ok(stream)
-    }
-
-    /// Open the output to start sending packets
-    pub unsafe fn open(&mut self) -> Result<()> {
-        if (*(*self.ctx).oformat).flags & AVFMT_NOFILE == 0 {
-            let ret = avio_open(&mut (*self.ctx).pb, (*self.ctx).url, AVIO_FLAG_WRITE);
-            bail_ffmpeg!(ret);
-        }
-
-        let ret = avformat_write_header(self.ctx, ptr::null_mut());
-        bail_ffmpeg!(ret);
-
-        av_dump_format(self.ctx, 0, (*self.ctx).url, 1);
-
-        Ok(())
-    }
-
-    /// Write a packet to the output
-    pub unsafe fn write_packet(&mut self, pkt: *mut AVPacket) -> Result<()> {
-        let stream = *(*self.ctx).streams.add((*pkt).stream_index as usize);
-        av_packet_rescale_ts(pkt, (*pkt).time_base, (*stream).time_base);
-        (*pkt).time_base = (*stream).time_base;
-
-        let ret = av_interleaved_write_frame(self.ctx, pkt);
-        bail_ffmpeg!(ret);
-        Ok(())
-    }
-
-    /// Close the output and write the trailer
-    pub unsafe fn close(self) -> Result<()> {
-        let ret = av_write_trailer(self.ctx);
-        bail_ffmpeg!(ret);
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::{generate_test_frame, Scaler};
-    use ffmpeg_sys_the_third::AVCodecID::AV_CODEC_ID_H264;
-    use ffmpeg_sys_the_third::AVPixelFormat::AV_PIX_FMT_YUV420P;
-    use ffmpeg_sys_the_third::AV_PROFILE_H264_MAIN;
-
-    #[test]
-    fn encode_mkv() -> Result<()> {
-        std::fs::create_dir_all("test_output")?;
-        unsafe {
-            let path = PathBuf::from("test_output/test.mp4");
-            let frame = generate_test_frame();
-
-            // convert frame to YUV
-            let mut scaler = Scaler::new();
-            let frame = scaler.process_frame(
-                frame,
-                (*frame).width as u16,
-                (*frame).height as u16,
-                AV_PIX_FMT_YUV420P,
-            )?;
-
-            let mut encoder = Encoder::new(AV_CODEC_ID_H264)?
-                .with_width((*frame).width)
-                .with_height((*frame).height)
-                .with_pix_fmt(AV_PIX_FMT_YUV420P)
-                .with_bitrate(1_000_000)
-                .with_framerate(30.0)
-                .with_profile(AV_PROFILE_H264_MAIN)
-                .with_level(50)
-                .open(None)?;
-
-            let mut muxer = Muxer::new()
-                .with_output(&path, None, None)?
-                .with_stream_encoder(&encoder)?;
-            muxer.open()?;
-            let mut pts = 0;
-            for _z in 0..100 {
-                (*frame).pts = pts;
-                for pkt in encoder.encode_frame(frame)? {
-                    muxer.write_packet(pkt)?;
-                }
-                pts += 1;
-            }
-            // flush
-            for f_pk in encoder.encode_frame(ptr::null_mut())? {
-                muxer.write_packet(f_pk)?;
-            }
-            muxer.close()?;
-        }
-        Ok(())
-    }
-}

src/transcode.rs

@@ -4,7 +4,6 @@ use crate::{
 use anyhow::Result;
 use ffmpeg_sys_the_third::{av_frame_free, av_packet_free};
 use std::collections::HashMap;
-use std::path::PathBuf;
 use std::ptr;
 
 /// A common transcoder task taking an input file
@@ -21,7 +20,9 @@ pub struct Transcoder {
 
 impl Transcoder {
     pub unsafe fn new(input: &str, output: &str) -> Result<Self> {
-        let muxer = Muxer::new().with_output(&PathBuf::from(output), None, None)?;
+        let muxer = Muxer::builder()
+            .with_output_path(output, None, None)?
+            .build()?;
 
         Ok(Self {
             demuxer: Demuxer::new(input)?,
@@ -168,8 +169,10 @@ mod tests {
     fn test_remux() -> Result<()> {
         unsafe {
             std::fs::create_dir_all("test_output")?;
-            let mut transcoder =
-                Transcoder::new("test_output/test.mp4", "test_output/test_transcode.mkv")?;
+            let mut transcoder = Transcoder::new(
+                "test_output/test_muxer.mp4",
+                "test_output/test_transcode.mkv",
+            )?;
             let info = transcoder.prepare()?;
             for c in info.streams {
                 transcoder.copy_stream(c)?;