use crate::io::byteio::ByteIOError;
use crate::io::bitreader::BitReaderError;
use crate::io::codebook::CodebookError;
+pub use crate::options::*;
+pub use std::str::FromStr;
/// A list specifying general decoding errors.
#[derive(Debug,Clone,Copy,PartialEq)]
}
/// Decoder trait.
-pub trait NADecoder {
+pub trait NADecoder: NAOptionHandler {
/// Initialises the decoder.
///
/// It takes [`NADecoderSupport`] allocated by the caller and `NACodecInfoRef` provided by demuxer.
/// Structure for registering known decoders.
///
-/// It is supposed to be filled using `register_all_codecs()` from some decoders crate and then it can be used to create decoders for the requested codecs.
+/// It is supposed to be filled using `register_all_decoders()` from some decoders crate and then it can be used to create decoders for the requested codecs.
#[derive(Default)]
pub struct RegisteredDecoders {
decs: Vec<DecoderInfo>,
self.decs.iter()
}
}
+
+/// Frame skipping mode for decoders.
+#[derive(Clone,Copy,PartialEq,Debug)]
+pub enum FrameSkipMode {
+ /// Decode all frames.
+ None,
+ /// Decode all key frames.
+ KeyframesOnly,
+ /// Decode only intra frames.
+ IntraOnly,
+}
+
+impl Default for FrameSkipMode {
+ fn default() -> Self {
+ FrameSkipMode::None
+ }
+}
+
+impl FromStr for FrameSkipMode {
+ type Err = DecoderError;
+
+ fn from_str(s: &str) -> Result<Self, Self::Err> {
+ match s {
+ FRAME_SKIP_OPTION_VAL_NONE => Ok(FrameSkipMode::None),
+ FRAME_SKIP_OPTION_VAL_KEYFRAME => Ok(FrameSkipMode::KeyframesOnly),
+ FRAME_SKIP_OPTION_VAL_INTRA => Ok(FrameSkipMode::IntraOnly),
+ _ => Err(DecoderError::InvalidData),
+ }
+ }
+}
+
+impl ToString for FrameSkipMode {
+ fn to_string(&self) -> String {
+ match *self {
+ FrameSkipMode::None => FRAME_SKIP_OPTION_VAL_NONE.to_string(),
+ FrameSkipMode::KeyframesOnly => FRAME_SKIP_OPTION_VAL_KEYFRAME.to_string(),
+ FrameSkipMode::IntraOnly => FRAME_SKIP_OPTION_VAL_INTRA.to_string(),
+ }
+ }
+}
+
+/// A list specifying general encoding errors.
+#[derive(Debug,Clone,Copy,PartialEq)]
+#[allow(dead_code)]
+pub enum EncoderError {
+ /// No frame was provided.
+ NoFrame,
+ /// Allocation failed.
+ AllocError,
+ /// Operation requires repeating.
+ TryAgain,
+ /// Input format is not supported by codec.
+ FormatError,
+ /// Invalid input parameters were provided.
+ InvalidParameters,
+ /// Feature is not implemented.
+ NotImplemented,
+ /// Some bug in encoder. It should not happen yet it might.
+ Bug,
+}
+
+/// A specialised `Result` type for decoding operations.
+pub type EncoderResult<T> = Result<T, EncoderError>;
+
+impl From<ByteIOError> for EncoderError {
+ fn from(_: ByteIOError) -> Self { EncoderError::Bug }
+}
+
+impl From<AllocatorError> for EncoderError {
+ fn from(_: AllocatorError) -> Self { EncoderError::AllocError }
+}
+
+/// Encoding parameter flag to force constant bitrate mode.
+pub const ENC_MODE_CBR: u64 = 1 << 0;
+/// Encoding parameter flag to force constant framerate mode.
+pub const ENC_MODE_CFR: u64 = 1 << 1;
+
+/// Encoding parameters.
+#[derive(Clone,Copy,PartialEq)]
+pub struct EncodeParameters {
+ /// Input format.
+ pub format: NACodecTypeInfo,
+ /// Time base numerator. Ignored for audio.
+ pub tb_num: u32,
+ /// Time base denominator. Ignored for audio.
+ pub tb_den: u32,
+ /// Bitrate in kilobits per second.
+ pub bitrate: u32,
+ /// A collection of various boolean encoder settings like CBR mode.
+ ///
+ /// See `ENC_MODE_*` constants for available options.
+ pub flags: u64,
+ /// Encoding quality.
+ pub quality: u8,
+}
+
+impl Default for EncodeParameters {
+ fn default() -> EncodeParameters {
+ EncodeParameters {
+ format: NACodecTypeInfo::None,
+ tb_num: 0,
+ tb_den: 0,
+ bitrate: 0,
+ flags: 0,
+ quality: 0,
+ }
+ }
+}
+
+/// Encoder trait.
+///
+/// Overall encoding is more complex than decoding.
+/// There are at least two issues that should be addressed: input format and the need for lookahead.
+///
+/// Some formats (like MPEG-1 ones) have fixed picture dimensions and framerate, or sampling rate.
+/// Some formats accept only pictures with dimensions being multiple of eight or sixteen.
+/// Some audio formats work only with monaural sound.
+/// In order to account for all this user first needs to check whether encoder can handle provided input format as is or some conversion is required.
+/// That is why `NAEncoder` has [`negotiate_format`] function that performs such check and returns what encoder can handle.
+///
+/// Additionally, encoders for complex formats often need several frames lookahead to encode data efficiently, actual frame encoding may take place only when some frames are accumulated.
+/// That is why encoder has two functions, one for queueing frames for encoding and one for obtaining encoded packets when they are available.
+/// In result encoder should first queue a frame for encoding with [`encode`] and then retrieve zero or more encoded packets with [`get_packet`] in a loop.
+///
+/// Overall encoding loop should look like this:
+/// ```ignore
+/// let encoder = ...; // create encoder
+/// let enc_params = encoder.negotiate_format(input_enc_params)?; // negotiate format
+/// let output_stream = encoder.init(stream_no, enc_params)?;
+/// while let Some(frame) = queue.get_frame() {
+/// // convert to the format encoder expects if required
+/// encoder.encode(frame)?;
+/// while let Some(enc_pkt) = encoder.get_packet()? {
+/// // send encoded packet to a muxer for example
+/// }
+/// }
+/// // retrieve the rest of encoded packets
+/// encoder.flush()?;
+/// while let Ok(enc_pkt) = encoder.get_packet()? {
+/// // send encoded packet to a muxer for example
+/// }
+/// ```
+///
+/// [`negotiate_format`]: ./trait.NAEncoder.html#tymethod.negotiate_format
+/// [`encode`]: ./trait.NAEncoder.html#tymethod.encode
+/// [`get_packet`]: ./trait.NAEncoder.html#tymethod.get_packet
+pub trait NAEncoder: NAOptionHandler {
+ /// Tries to negotiate input format.
+ ///
+ /// This function takes input encoding parameters and returns adjusted encoding parameters if input ones make sense.
+ /// If input parameters are empty then the default parameters are returned.
+ ///
+ /// # Example
+ /// ```ignore
+ /// let enc_params = [ EncodeParameters {...}, ..., EncodeParameters::default() ];
+ /// let mut target_params = EncodeParameters::default();
+ /// for params in enc_params.iter() {
+ /// if let Ok(dparams) = encoder.negotiate_format(params) {
+ /// target_params = dparams;
+ /// break;
+ /// }
+ /// }
+ /// // since negotiate_format(EncodeParameters::default()) will return a valid format, target_params should be valid here
+ /// let stream = encoder.init(stream_id, target_params)?;
+ /// // convert input into format defined in target_params, feed to the encoder, ...
+ /// ```
+ fn negotiate_format(&self, encinfo: &EncodeParameters) -> EncoderResult<EncodeParameters>;
+ /// Initialises the encoder.
+ fn init(&mut self, stream_id: u32, encinfo: EncodeParameters) -> EncoderResult<NAStreamRef>;
+ /// Takes a single frame for encoding.
+ fn encode(&mut self, frm: &NAFrame) -> EncoderResult<()>;
+ /// Returns encoded packet if available.
+ fn get_packet(&mut self) -> EncoderResult<Option<NAPacket>>;
+ /// Tells encoder to encode all data it currently has.
+ fn flush(&mut self) -> EncoderResult<()>;
+}
+
+/// Encoder information used during creating an encoder for requested codec.
+#[derive(Clone,Copy)]
+pub struct EncoderInfo {
+ /// Short encoder name.
+ pub name: &'static str,
+ /// The function that creates an encoder instance.
+ pub get_encoder: fn () -> Box<dyn NAEncoder + Send>,
+}
+
+/// Structure for registering known encoders.
+///
+/// It is supposed to be filled using `register_all_decoders()` from some encoders crate and then it can be used to create encoders for the requested codecs.
+#[derive(Default)]
+pub struct RegisteredEncoders {
+ encs: Vec<EncoderInfo>,
+}
+
+impl RegisteredEncoders {
+ /// Constructs a new instance of `RegisteredEncoders`.
+ pub fn new() -> Self {
+ Self { encs: Vec::new() }
+ }
+ /// Adds another encoder to the registry.
+ pub fn add_encoder(&mut self, enc: EncoderInfo) {
+ self.encs.push(enc);
+ }
+ /// Searches for the encoder for the provided name and returns a function for creating it on success.
+ pub fn find_encoder(&self, name: &str) -> Option<fn () -> Box<dyn NAEncoder + Send>> {
+ for &enc in self.encs.iter() {
+ if enc.name == name {
+ return Some(enc.get_encoder);
+ }
+ }
+ None
+ }
+ /// Provides an iterator over currently registered encoders.
+ pub fn iter(&self) -> std::slice::Iter<EncoderInfo> {
+ self.encs.iter()
+ }
+}
+
projects / nihav.git / blobdiff