Revise transcode_aac example and various updates (#147)

* More methods for `AVAudioFifo`, Remove unused error variants

* Make `SwrContext::convert` accept raw data by default, Remove `SwrContext::convert_raw`

* Add `pkt_timebase` setter for `AVCodecContext`

* Make `AVAudioFifo::write` returns nothing on success

* Add `AVFrame::get_buffer`

* Change `AVSamples` from vec to boxed slice

* Remove unnecessary error variant

src/avcodec/codec.rs

@@ -127,6 +127,7 @@ settable!(AVCodecContext {
     sample_aspect_ratio: AVRational,
     pix_fmt: i32,
     time_base: AVRational,
+    pkt_timebase: AVRational,
     sample_rate: i32,
     channels: i32,
     sample_fmt: i32,

src/avformat/avformat.rs

@@ -147,7 +147,7 @@ impl AVFormatContextInput {
         match unsafe { ffi::av_read_frame(self.as_mut_ptr(), packet.as_mut_ptr()) }.upgrade() {
             Ok(_) => Ok(Some(packet)),
             Err(ffi::AVERROR_EOF) => Ok(None),
-            Err(x) => Err(RsmpegError::ReadFrameError(x)),
+            Err(x) => Err(x)?,
         }
     }
 
@@ -340,9 +340,7 @@ impl AVFormatContextOutput {
     /// libavformat to handle the interleaving should call
     /// [`Self::interleaved_write_frame()`] instead of this function.
     pub fn write_frame(&mut self, packet: &mut AVPacket) -> Result<()> {
-        unsafe { ffi::av_write_frame(self.as_mut_ptr(), packet.as_mut_ptr()) }
-            .upgrade()
-            .map_err(RsmpegError::WriteFrameError)?;
+        unsafe { ffi::av_write_frame(self.as_mut_ptr(), packet.as_mut_ptr()) }.upgrade()?;
         Ok(())
     }
 

src/avutil/audio_fifo.rs

@@ -1,44 +1,25 @@
 use crate::{error::*, ffi, shared::*};
 use std::ops::Drop;
-wrap!(AVAudioFifo: ffi::AVAudioFifo);
+
+wrap!(
+    /// Context for an Audio FIFO Buffer.
+    ///
+    /// - Operates at the sample level rather than the byte level.
+    /// - Supports multiple channels with either planar or packed sample format.
+    /// - Automatic reallocation when writing to a full buffer.
+    AVAudioFifo: ffi::AVAudioFifo
+);
 
 impl AVAudioFifo {
+    /// Allocate an AVAudioFifo.
     pub fn new(sample_fmt: ffi::AVSampleFormat, channels: i32, nb_samples: i32) -> Self {
         let fifo = unsafe { ffi::av_audio_fifo_alloc(sample_fmt, channels, nb_samples) }
             .upgrade()
             .unwrap();
         unsafe { Self::from_raw(fifo) }
     }
 
-    /// Get the current number of samples in the [`AVAudioFifo`] available for
-    /// reading.
-    pub fn size(&self) -> i32 {
-        unsafe {
-            // function doesn't modify self, casting safe
-            ffi::av_audio_fifo_size(self.as_ptr() as *mut _)
-        }
-    }
-
-    /// Get the current number of samples in the [`AVAudioFifo`] available for
-    /// writing.
-    pub fn space(&self) -> i32 {
-        unsafe {
-            // function doesn't modify self, casting safe
-            ffi::av_audio_fifo_space(self.as_ptr() as *mut _)
-        }
-    }
-
-    pub fn reset(&mut self) {
-        unsafe { ffi::av_audio_fifo_reset(self.as_mut_ptr()) }
-    }
-
-    pub fn drain(&mut self, nb_samples: i32) {
-        // FFI function only error when the nb_samples is negative.
-        unsafe { ffi::av_audio_fifo_drain(self.as_mut_ptr(), nb_samples) }
-            .upgrade()
-            .unwrap();
-    }
-
+    /// Reallocate an AVAudioFifo.
     pub fn realloc(&mut self, nb_samples: i32) {
         // Almost only panic on no memory, in other cases panic on invalid
         // parameters which is not possible with current good API.
@@ -47,28 +28,91 @@ impl AVAudioFifo {
             .unwrap();
     }
 
-    /// Write data to an AVAudioFifo. If successful, the number of samples
-    /// actually written will always be nb_samples.
+    /// Write data to an AVAudioFifo.
     ///
     /// The AVAudioFifo will be reallocated automatically if the available space
     /// is less than nb_samples.
     ///
     /// # Safety
     /// Function is safe when the `data` points to valid samples.
-    pub unsafe fn write(&mut self, data: *const *mut u8, nb_samples: i32) -> Result<i32> {
-        unsafe { ffi::av_audio_fifo_write(self.as_mut_ptr(), data as *mut _, nb_samples) }
-            .upgrade()
-            .map_err(RsmpegError::AudioFifoWriteError)
+    pub unsafe fn write(&mut self, data: *const *mut u8, nb_samples: i32) -> Result<()> {
+        let ret = unsafe { ffi::av_audio_fifo_write(self.as_mut_ptr(), data as _, nb_samples) }
+            .upgrade()?;
+        debug_assert_eq!(ret, nb_samples);
+        Ok(())
+    }
+
+    /// Peek data from an AVAudioFifo.
+    ///
+    /// # Safety
+    /// Function is safe when the `data` points to valid sample buffer.
+    pub unsafe fn peek(&mut self, data: *const *mut u8, nb_samples: i32) -> Result<i32> {
+        let ret = unsafe { ffi::av_audio_fifo_peek(self.as_mut_ptr(), data as _, nb_samples) }
+            .upgrade()?;
+        Ok(ret)
     }
 
-    /// Return actually read size if success.
+    /// Peek data from an AVAudioFifo.
+    ///
+    /// # Safety
+    /// Function is safe when the `data` points to valid sample buffer.
+    pub unsafe fn peek_at(
+        &mut self,
+        data: *const *mut u8,
+        nb_samples: i32,
+        offset: i32,
+    ) -> Result<i32> {
+        let ret =
+            unsafe { ffi::av_audio_fifo_peek_at(self.as_mut_ptr(), data as _, nb_samples, offset) }
+                .upgrade()?;
+        Ok(ret)
+    }
+
+    /// Read data from an AVAudioFifo.
+    ///
+    /// This function returns actually read size if success.
     ///
     /// # Safety
     /// Function is safe when the `data` points to valid array such as AVFrame::data.
-    pub unsafe fn read(&mut self, data: *mut *mut u8, nb_samples: i32) -> Result<i32> {
-        unsafe { ffi::av_audio_fifo_read(self.as_mut_ptr(), data as _, nb_samples) }
+    pub unsafe fn read(&mut self, data: *const *mut u8, nb_samples: i32) -> Result<i32> {
+        let ret = unsafe { ffi::av_audio_fifo_read(self.as_mut_ptr(), data as _, nb_samples) }
+            .upgrade()?;
+        Ok(ret)
+    }
+
+    /// Drain data from an AVAudioFifo.
+    ///
+    /// Removes the data without reading it.
+    pub fn drain(&mut self, nb_samples: i32) {
+        // FFI function only error when the nb_samples is negative.
+        unsafe { ffi::av_audio_fifo_drain(self.as_mut_ptr(), nb_samples) }
             .upgrade()
-            .map_err(RsmpegError::AudioFifoReadError)
+            .unwrap();
+    }
+
+    /// Reset the AVAudioFifo buffer.
+    ///
+    /// This empties all data in the buffer.
+    pub fn reset(&mut self) {
+        unsafe { ffi::av_audio_fifo_reset(self.as_mut_ptr()) }
+    }
+
+    /// Get the current number of samples in the [`AVAudioFifo`] available for
+    /// reading.
+    pub fn size(&self) -> i32 {
+        unsafe {
+            // function doesn't modify self, casting safe
+            ffi::av_audio_fifo_size(self.as_ptr() as *mut _)
+        }
+    }
+
+    /// Get the current number of samples in the [`AVAudioFifo`] available for
+    /// writing.
+    pub fn space(&self) -> i32 {
+        unsafe {
+            // function doesn't modify self, casting safe
+            ffi::av_audio_fifo_space(self.as_ptr() as *mut _)
+        }
     }
 }
 

src/avutil/frame.rs

@@ -73,6 +73,21 @@ impl AVFrame {
         Ok(())
     }
 
+    /// Allocate new buffer(s) for audio or video data.
+    ///
+    /// The following fields must be set on frame before calling this function:
+    /// - format (pixel format for video, sample format for audio)
+    /// - width and height for video
+    /// - nb_samples and ch_layout for audio
+    ///
+    /// This function will fill AVFrame.data and AVFrame.buf arrays and, if
+    /// necessary, allocate and fill AVFrame.extended_data and AVFrame.extended_buf.
+    /// For planar formats, one buffer will be allocated for each plane.
+    pub fn get_buffer(&mut self, align: i32) -> Result<()> {
+        unsafe { ffi::av_frame_get_buffer(self.as_mut_ptr(), align) }.upgrade()?;
+        Ok(())
+    }
+
     pub fn data_mut(&mut self) -> &mut [*mut u8; 8] {
         unsafe { &mut self.deref_mut().data }
     }

src/avutil/samplefmt.rs

@@ -120,11 +120,11 @@ pub fn sample_fmt_is_planar(sample_fmt: AVSampleFormat) -> bool {
 // > but for planar audio with more channels that can fit in data,
 // > extended_data must be used in order to access all channels.
 //
-// This is the reason why `AVSamples` has a vector of channels for containing
+// This is the reason why `AVSamples` has a vector of channels for holding
 // audio data.
 wrap! {
-    AVSamples: Vec<u8>,
-    audio_data: Vec<*mut u8> = Vec::new(),
+    AVSamples: Box<[u8]>,
+    audio_data: Box<[*mut u8]> = Vec::new().into_boxed_slice(),
     linesize: i32 = 0,
     nb_channels: i32 = 0,
     nb_samples: i32 = 0,
@@ -183,22 +183,22 @@ impl AVSamples {
         // Implementation inspired by `av_samples_alloc_array_and_samples` and `av_samples_alloc`.
         let (_, buffer_size) =
             AVSamples::get_buffer_size(nb_channels, nb_samples, sample_fmt, align)?;
-        let linear = vec![0u8; buffer_size as usize];
+        let buffer = vec![0u8; buffer_size as usize].into_boxed_slice();
 
         let nb_planes = if sample_fmt_is_planar(sample_fmt) {
             nb_channels
         } else {
             1
         };
-        let mut audio_data = vec![ptr::null_mut(); nb_planes as usize];
+        let mut audio_data = vec![ptr::null_mut(); nb_planes as usize].into_boxed_slice();
         let mut linesize = 0;
         // From the documentation, this function only error on no memory, so
         // unwrap.
         unsafe {
             ffi::av_samples_fill_arrays(
                 audio_data.as_mut_ptr(),
                 &mut linesize,
-                linear.as_ptr(),
+                buffer.as_ptr(),
                 nb_channels,
                 nb_samples,
                 sample_fmt,
@@ -209,9 +209,9 @@ impl AVSamples {
         .unwrap();
 
         // Leaks a Vec.
-        let linear = Box::leak(Box::new(linear));
+        let buffer = Box::leak(Box::new(buffer));
 
-        let mut samples = unsafe { AVSamples::from_raw(NonNull::new(linear).unwrap()) };
+        let mut samples = unsafe { AVSamples::from_raw(NonNull::new(buffer).unwrap()) };
         samples.audio_data = audio_data;
         samples.linesize = linesize;
         samples.nb_channels = nb_channels;

src/error.rs

@@ -80,10 +80,6 @@ pub enum RsmpegError {
     #[error("Failed to initialize bitstream filter context. ({0})")]
     BitstreamInitializationError(c_int),
 
-    #[error("Read frame to an input format context failed. ({0})")]
-    ReadFrameError(c_int),
-    #[error("Write frame to an output format context failed. ({0})")]
-    WriteFrameError(c_int),
     #[error("Interleaved write frame to an output format context failed. ({0})")]
     InterleavedWriteFrameError(c_int),
 
@@ -104,19 +100,9 @@ pub enum RsmpegError {
     #[error("AVIO Open failure. ({0})")]
     AVIOOpenError(c_int),
 
-    #[error("SwrContext init failed. ({0})")]
-    SwrContextInitError(c_int),
-    #[error("SwrContext converting data failed. ({0})")]
-    SwrConvertError(c_int),
-
     #[error("SwsContext scale failed. ({0})")]
     SwsScaleError(c_int),
 
-    #[error("AudioFifo write failed. ({0})")]
-    AudioFifoWriteError(c_int),
-    #[error("AudioFifo read failed. ({0})")]
-    AudioFifoReadError(c_int),
-
     #[error("AVFrame buffer double allocating.")]
     AVFrameDoubleAllocatingError,
     #[error("AVFrame buffer allocating with incorrect parameters. ({0})")]
@@ -153,19 +139,13 @@ impl RsmpegError {
             | Self::BitstreamSendPacketError(err)
             | Self::BitstreamReceivePacketError(err)
             | Self::BitstreamInitializationError(err)
-            | Self::ReadFrameError(err)
-            | Self::WriteFrameError(err)
             | Self::InterleavedWriteFrameError(err)
             | Self::BufferSrcAddFrameError(err)
             | Self::BufferSinkGetFrameError(err)
             | Self::DictionaryParseError(err)
             | Self::DictionaryGetStringError(err)
             | Self::AVIOOpenError(err)
-            | Self::SwrContextInitError(err)
-            | Self::SwrConvertError(err)
             | Self::SwsScaleError(err)
-            | Self::AudioFifoWriteError(err)
-            | Self::AudioFifoReadError(err)
             | Self::AVFrameInvalidAllocatingError(err)
             | Self::AVImageFillArrayError(err) => Some(*err),
 

src/macros.rs

@@ -198,11 +198,12 @@ macro_rules! wrap_mut {
 /// Wrapping with XXX, XXX -> XXX.
 macro_rules! wrap {
     (
+        $(#[$meta:meta])*
         $name: ident: $ffi_type: ty
         $(,$attach: ident: $attach_type: ty = $attach_default: expr)* $(,)?
     ) => {
         paste::paste! {
-            wrap_pure!(($name): $ffi_type $(,$attach: $attach_type = $attach_default)*);
+            wrap_pure!($(#[$meta])* ($name): $ffi_type $(,$attach: $attach_type = $attach_default)*);
         }
     };
 }