feat: encoder

.gitignore

@@ -1,2 +1,4 @@
 /target
 /.idea
+
+test.png

src/encode.rs

@@ -0,0 +1,207 @@
+use std::collections::HashMap;
+use std::{ptr, slice};
+
+use crate::{get_ffmpeg_error_msg, options_to_dict, return_ffmpeg_error};
+use anyhow::{bail, Error};
+use ffmpeg_sys_the_third::{
+    av_channel_layout_default, av_packet_alloc, av_packet_free, avcodec_alloc_context3,
+    avcodec_find_encoder, avcodec_get_supported_config, avcodec_open2, avcodec_receive_packet,
+    avcodec_send_frame, AVChannelLayout, AVCodec, AVCodecConfig, AVCodecContext, AVCodecID,
+    AVFrame, AVPacket, AVPixelFormat, AVRational, AVSampleFormat, AVERROR, AVERROR_EOF,
+};
+use libc::EAGAIN;
+
+pub struct Encoder {
+    ctx: *mut AVCodecContext,
+    codec: *const AVCodec,
+}
+
+unsafe impl Send for Encoder {}
+
+impl Encoder {
+    /// Create a new encoder with the specified codec
+    pub fn new(codec: AVCodecID) -> Result<Self, Error> {
+        unsafe {
+            let codec = avcodec_find_encoder(codec);
+            if codec.is_null() {
+                bail!("codec not found");
+            }
+            let ctx = avcodec_alloc_context3(codec);
+            if ctx.is_null() {
+                bail!("context allocation failed");
+            }
+            // set some defaults
+            (*ctx).time_base = AVRational { num: 1, den: 1 };
+            Ok(Self { ctx, codec })
+        }
+    }
+
+    /// List supported configs (see [avcodec_get_supported_config])
+    pub unsafe fn list_configs<'a, T>(&mut self, cfg: AVCodecConfig) -> Result<&'a [T], Error> {
+        let mut dst = ptr::null_mut();
+        let mut num_dst = 0;
+        let ret = avcodec_get_supported_config(
+            self.ctx,
+            self.codec,
+            cfg,
+            0,
+            ptr::addr_of_mut!(dst) as _,
+            &mut num_dst,
+        );
+        return_ffmpeg_error!(ret);
+        Ok(slice::from_raw_parts(dst, num_dst as usize))
+    }
+
+    /// Set the encoder timebase
+    pub unsafe fn with_timebase(self, timebase: AVRational) -> Self {
+        (*self.ctx).time_base = timebase;
+        self
+    }
+
+    /// Set the encoder bitrate
+    pub unsafe fn with_bitrate(self, bitrate: i64) -> Self {
+        (*self.ctx).bit_rate = bitrate;
+        self
+    }
+
+    /// Set the encoder sample rate (audio)
+    pub unsafe fn with_sample_rate(self, fmt: i32) -> Self {
+        (*self.ctx).sample_rate = fmt;
+        self
+    }
+
+    /// Set the encoder width in pixels
+    pub unsafe fn with_width(self, width: i32) -> Self {
+        (*self.ctx).width = width;
+        self
+    }
+
+    /// Set the encoder height in pixels
+    pub unsafe fn with_height(self, height: i32) -> Self {
+        (*self.ctx).height = height;
+        self
+    }
+
+    /// Set the encoder level (see AV_LEVEL_*)
+    pub unsafe fn with_level(self, level: i32) -> Self {
+        (*self.ctx).level = level;
+        self
+    }
+
+    /// Set the encoder profile (see AV_PROFILE_*)
+    pub unsafe fn with_profile(self, profile: i32) -> Self {
+        (*self.ctx).profile = profile;
+        self
+    }
+
+    /// Set the encoder profile (see AV_PROFILE_*)
+    pub unsafe fn with_framerate(self, rate: AVRational) -> Self {
+        (*self.ctx).framerate = rate;
+        self
+    }
+
+    /// Set the encoder pixel format
+    pub unsafe fn with_pix_fmt(self, fmt: AVPixelFormat) -> Self {
+        (*self.ctx).pix_fmt = fmt;
+        self
+    }
+
+    /// Set the encoder sample format (audio)
+    pub unsafe fn with_sample_format(self, fmt: AVSampleFormat) -> Self {
+        (*self.ctx).sample_fmt = fmt;
+        self
+    }
+
+    /// Set the encoder channel layout (audio)
+    pub unsafe fn with_channel_layout(self, layout: AVChannelLayout) -> Self {
+        (*self.ctx).ch_layout = layout;
+        self
+    }
+
+    /// Set the encoder channel layout using number of channels (audio)
+    pub unsafe fn with_default_channel_layout(self, channels: i32) -> Self {
+        let mut layout = AVChannelLayout::empty();
+        av_channel_layout_default(&mut layout, channels);
+        (*self.ctx).ch_layout = layout;
+        self
+    }
+
+    /// Apply options to context
+    pub unsafe fn with_options<F>(self, fx: F) -> Self
+    where
+        F: FnOnce(*mut AVCodecContext),
+    {
+        fx(self.ctx);
+        self
+    }
+
+    /// Open the encoder so that you can start encoding frames (see [avcodec_open2])
+    pub unsafe fn open(self, options: Option<HashMap<String, String>>) -> Result<Self, Error> {
+        let mut options = if let Some(options) = options {
+            options_to_dict(options)?
+        } else {
+            ptr::null_mut()
+        };
+        let ret = avcodec_open2(self.ctx, self.codec, &mut options);
+        return_ffmpeg_error!(ret);
+        Ok(self)
+    }
+
+    /// Encode a frame, returning a number of [AVPacket]
+    pub unsafe fn encode_frame(
+        &mut self,
+        frame: *mut AVFrame,
+    ) -> Result<Vec<*mut AVPacket>, Error> {
+        let mut pkgs = Vec::new();
+
+        let mut ret = avcodec_send_frame(self.ctx, frame);
+        if ret < 0 && ret != AVERROR(EAGAIN) {
+            bail!(get_ffmpeg_error_msg(ret));
+        }
+
+        while ret >= 0 || ret == AVERROR(EAGAIN) {
+            let mut pkt = av_packet_alloc();
+            ret = avcodec_receive_packet(self.ctx, pkt);
+            if ret != 0 {
+                av_packet_free(&mut pkt);
+                if ret == AVERROR(EAGAIN) || ret == AVERROR_EOF {
+                    break;
+                }
+                bail!(get_ffmpeg_error_msg(ret));
+            }
+            pkgs.push(pkt);
+        }
+
+        Ok(pkgs)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::generate_test_frame;
+    use std::io::Write;
+
+    #[test]
+    fn test_encode_png() -> Result<(), Error> {
+        unsafe {
+            let frame = generate_test_frame();
+            let mut encoder = Encoder::new(AVCodecID::AV_CODEC_ID_PNG)?
+                .with_width(512)
+                .with_height(512);
+
+            let pix_fmts: &[AVPixelFormat] =
+                encoder.list_configs(AVCodecConfig::AV_CODEC_CONFIG_PIX_FORMAT)?;
+            encoder = encoder.with_pix_fmt(pix_fmts[0]).open(None)?;
+
+            let mut test_file = std::fs::File::create("test.png")?;
+            let mut pkts = encoder.encode_frame(frame)?;
+            let flush_pkts = encoder.encode_frame(ptr::null_mut())?;
+            pkts.extend(flush_pkts);
+            for pkt in pkts {
+                test_file.write(slice::from_raw_parts((*pkt).data, (*pkt).size as usize))?;
+            }
+        }
+        Ok(())
+    }
+}

src/lib.rs

@@ -9,6 +9,7 @@ use std::ptr;
 
 mod decode;
 mod demux;
+mod encode;
 mod filter;
 mod resample;
 mod scale;
@@ -128,6 +129,36 @@ pub unsafe fn get_frame_from_hw(mut frame: *mut AVFrame) -> Result<*mut AVFrame,
     }
 }
 
+#[cfg(test)]
+pub unsafe fn generate_test_frame() -> *mut AVFrame {
+    use ffmpeg_sys_the_third::{av_frame_get_buffer, AVPixelFormat};
+    use std::mem::transmute;
+
+    let frame = av_frame_alloc();
+    (*frame).width = 512;
+    (*frame).height = 512;
+    (*frame).format = transmute(AVPixelFormat::AV_PIX_FMT_RGB24);
+    av_frame_get_buffer(frame, 0);
+
+    let mut lx = 0;
+    for line in 0..(*frame).height {
+        let c = lx % 3;
+        for y in 0..(*frame).width as usize {
+            let ptr = (*frame).data[0];
+            let offset = (line * (*frame).linesize[0]) as usize + (y * 3);
+            match c {
+                0 => *ptr.add(offset) = 0xff,
+                1 => *ptr.add(offset + 1) = 0xff,
+                2 => *ptr.add(offset + 2) = 0xff,
+                _ => {}
+            }
+        }
+        lx += 1;
+    }
+
+    frame
+}
+
 pub use decode::*;
 pub use demux::*;
 pub use ffmpeg_sys_the_third;

src/scale.rs

@@ -123,23 +123,13 @@ impl Scaler {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use ffmpeg_sys_the_third::{
-        av_frame_alloc, av_frame_free, av_frame_get_buffer, AVFrame, AVPixelFormat,
-    };
-
-    unsafe fn blank_frame() -> *mut AVFrame {
-        let frame = av_frame_alloc();
-        (*frame).width = 512;
-        (*frame).height = 512;
-        (*frame).format = AVPixelFormat::AV_PIX_FMT_RGB24 as libc::c_int;
-        av_frame_get_buffer(frame, 0);
-        frame
-    }
+    use crate::generate_test_frame;
+    use ffmpeg_sys_the_third::{av_frame_free, AVPixelFormat};
 
     #[test]
     fn scale_rgb24_yuv420() {
         unsafe {
-            let mut frame = blank_frame();
+            let mut frame = generate_test_frame();
             let mut scaler = Scaler::new();
 
             // downscale