nihav-core/src/codecs/mod.rs

   1 //! Decoder interface definitions.
   2 pub use crate::frame::*;
   3 use crate::io::byteio::ByteIOError;
   4 use crate::io::bitreader::BitReaderError;
   5 use crate::io::codebook::CodebookError;
   6 pub use crate::options::*;
   7 pub use std::str::FromStr;
   8
   9 /// A list specifying general decoding errors.
  10 #[derive(Debug,Clone,Copy,PartialEq)]
  11 #[allow(dead_code)]
  12 pub enum DecoderError {
  13     /// No frame was provided.
  14     NoFrame,
  15     /// Allocation failed.
  16     AllocError,
  17     /// Operation requires repeating.
  18     TryAgain,
  19     /// Invalid input data was provided.
  20     InvalidData,
  21     /// Checksum verification failed.
  22     ChecksumError,
  23     /// Provided input turned out to be incomplete.
  24     ShortData,
  25     /// Decoder could not decode provided frame because it references some missing previous frame.
  26     MissingReference,
  27     /// Feature is not implemented.
  28     NotImplemented,
  29     /// Some bug in decoder. It should not happen yet it might.
  30     Bug,
  31 }
  32
  33 /// A specialised `Result` type for decoding operations.
  34 pub type DecoderResult<T> = Result<T, DecoderError>;
  35
  36 impl From<ByteIOError> for DecoderError {
  37     fn from(_: ByteIOError) -> Self { DecoderError::ShortData }
  38 }
  39
  40 impl From<BitReaderError> for DecoderError {
  41     fn from(e: BitReaderError) -> Self {
  42         match e {
  43             BitReaderError::BitstreamEnd => DecoderError::ShortData,
  44             _ => DecoderError::InvalidData,
  45         }
  46     }
  47 }
  48
  49 impl From<CodebookError> for DecoderError {
  50     fn from(_: CodebookError) -> Self { DecoderError::InvalidData }
  51 }
  52
  53 impl From<AllocatorError> for DecoderError {
  54     fn from(_: AllocatorError) -> Self { DecoderError::AllocError }
  55 }
  56
  57 /// Auxiliary structure for storing data used by decoder but also controlled by the caller.
  58 pub struct NADecoderSupport {
  59     /// Frame buffer pool for 8-bit or packed video frames.
  60     pub pool_u8:        NAVideoBufferPool<u8>,
  61     /// Frame buffer pool for 16-bit video frames.
  62     pub pool_u16:       NAVideoBufferPool<u16>,
  63     /// Frame buffer pool for 32-bit video frames.
  64     pub pool_u32:       NAVideoBufferPool<u32>,
  65 }
  66
  67 impl NADecoderSupport {
  68     /// Constructs a new instance of `NADecoderSupport`.
  69     pub fn new() -> Self {
  70         Self {
  71             pool_u8:        NAVideoBufferPool::new(0),
  72             pool_u16:       NAVideoBufferPool::new(0),
  73             pool_u32:       NAVideoBufferPool::new(0),
  74         }
  75     }
  76 }
  77
  78 impl Default for NADecoderSupport {
  79     fn default() -> Self { Self::new() }
  80 }
  81
  82 /// Decoder trait.
  83 pub trait NADecoder: NAOptionHandler {
  84     /// Initialises the decoder.
  85     ///
  86     /// It takes [`NADecoderSupport`] allocated by the caller and `NACodecInfoRef` provided by demuxer.
  87     ///
  88     /// [`NADecoderSupport`]: ./struct.NADecoderSupport.html
  89     fn init(&mut self, supp: &mut NADecoderSupport, info: NACodecInfoRef) -> DecoderResult<()>;
  90     /// Decodes a single frame.
  91     fn decode(&mut self, supp: &mut NADecoderSupport, pkt: &NAPacket) -> DecoderResult<NAFrameRef>;
  92     /// Tells decoder to clear internal state (e.g. after error or seeking).
  93     fn flush(&mut self);
  94 }
  95
  96 /// Decoder information used during creating a decoder for requested codec.
  97 #[derive(Clone,Copy)]
  98 pub struct DecoderInfo {
  99     /// Short decoder name.
 100     pub name: &'static str,
 101     /// The function that creates a decoder instance.
 102     pub get_decoder: fn () -> Box<dyn NADecoder + Send>,
 103 }
 104
 105 /// Structure for registering known decoders.
 106 ///
 107 /// 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.
 108 #[derive(Default)]
 109 pub struct RegisteredDecoders {
 110     decs:   Vec<DecoderInfo>,
 111 }
 112
 113 impl RegisteredDecoders {
 114     /// Constructs a new instance of `RegisteredDecoders`.
 115     pub fn new() -> Self {
 116         Self { decs: Vec::new() }
 117     }
 118     /// Adds another decoder to the registry.
 119     pub fn add_decoder(&mut self, dec: DecoderInfo) {
 120         self.decs.push(dec);
 121     }
 122     /// Searches for the decoder for the provided name and returns a function for creating it on success.
 123     pub fn find_decoder(&self, name: &str) -> Option<fn () -> Box<dyn NADecoder + Send>> {
 124         for &dec in self.decs.iter() {
 125             if dec.name == name {
 126                 return Some(dec.get_decoder);
 127             }
 128         }
 129         None
 130     }
 131     /// Provides an iterator over currently registered decoders.
 132     pub fn iter(&self) -> std::slice::Iter<DecoderInfo> {
 133         self.decs.iter()
 134     }
 135 }
 136
 137 /// Frame skipping mode for decoders.
 138 #[derive(Clone,Copy,PartialEq,Debug)]
 139 pub enum FrameSkipMode {
 140     /// Decode all frames.
 141     None,
 142     /// Decode all key frames.
 143     KeyframesOnly,
 144     /// Decode only intra frames.
 145     IntraOnly,
 146 }
 147
 148 impl Default for FrameSkipMode {
 149     fn default() -> Self {
 150         FrameSkipMode::None
 151     }
 152 }
 153
 154 impl FromStr for FrameSkipMode {
 155     type Err = DecoderError;
 156
 157     fn from_str(s: &str) -> Result<Self, Self::Err> {
 158         match s {
 159             FRAME_SKIP_OPTION_VAL_NONE      => Ok(FrameSkipMode::None),
 160             FRAME_SKIP_OPTION_VAL_KEYFRAME  => Ok(FrameSkipMode::KeyframesOnly),
 161             FRAME_SKIP_OPTION_VAL_INTRA     => Ok(FrameSkipMode::IntraOnly),
 162             _ => Err(DecoderError::InvalidData),
 163         }
 164     }
 165 }
 166
 167 impl ToString for FrameSkipMode {
 168     fn to_string(&self) -> String {
 169         match *self {
 170             FrameSkipMode::None             => FRAME_SKIP_OPTION_VAL_NONE.to_string(),
 171             FrameSkipMode::KeyframesOnly    => FRAME_SKIP_OPTION_VAL_KEYFRAME.to_string(),
 172             FrameSkipMode::IntraOnly        => FRAME_SKIP_OPTION_VAL_INTRA.to_string(),
 173         }
 174     }
 175 }
 176
 177 /// A list specifying general encoding errors.
 178 #[derive(Debug,Clone,Copy,PartialEq)]
 179 #[allow(dead_code)]
 180 pub enum EncoderError {
 181     /// No frame was provided.
 182     NoFrame,
 183     /// Allocation failed.
 184     AllocError,
 185     /// Operation requires repeating.
 186     TryAgain,
 187     /// Input format is not supported by codec.
 188     FormatError,
 189     /// Invalid input parameters were provided.
 190     InvalidParameters,
 191     /// Feature is not implemented.
 192     NotImplemented,
 193     /// Some bug in encoder. It should not happen yet it might.
 194     Bug,
 195 }
 196
 197 /// A specialised `Result` type for decoding operations.
 198 pub type EncoderResult<T> = Result<T, EncoderError>;
 199
 200 impl From<ByteIOError> for EncoderError {
 201     fn from(_: ByteIOError) -> Self { EncoderError::Bug }
 202 }
 203
 204 impl From<AllocatorError> for EncoderError {
 205     fn from(_: AllocatorError) -> Self { EncoderError::AllocError }
 206 }
 207
 208 /// Encoding parameter flag to force constant bitrate mode.
 209 pub const ENC_MODE_CBR: u64 = 1 << 0;
 210 /// Encoding parameter flag to force constant framerate mode.
 211 pub const ENC_MODE_CFR: u64 = 1 << 1;
 212
 213 /// Encoder supports constant bitrate mode.
 214 pub const ENC_CAPS_CBR: u64 = 1 << 0;
 215 /// Encoder supports skip frames.
 216 pub const ENC_CAPS_SKIPFRAME: u64 = 1 << 1;
 217 /// Encoder supports mid-stream parameters change.
 218 pub const ENC_CAPS_PARAMCHANGE: u64 = 1 << 2;
 219
 220 /// Encoding parameters.
 221 #[derive(Clone,Copy,PartialEq)]
 222 pub struct EncodeParameters {
 223     /// Input format.
 224     pub format:     NACodecTypeInfo,
 225     /// Time base numerator. Ignored for audio.
 226     pub tb_num:     u32,
 227     /// Time base denominator. Ignored for audio.
 228     pub tb_den:     u32,
 229     /// Bitrate in bits per second.
 230     pub bitrate:    u32,
 231     /// A collection of various boolean encoder settings like CBR mode.
 232     ///
 233     /// See `ENC_MODE_*` constants for available options.
 234     pub flags:      u64,
 235     /// Encoding quality.
 236     pub quality:    u8,
 237 }
 238
 239 impl Default for EncodeParameters {
 240     fn default() -> EncodeParameters {
 241         EncodeParameters {
 242             format:     NACodecTypeInfo::None,
 243             tb_num:     0,
 244             tb_den:     0,
 245             bitrate:    0,
 246             flags:      0,
 247             quality:    0,
 248         }
 249     }
 250 }
 251
 252 /// Encoder trait.
 253 ///
 254 /// Overall encoding is more complex than decoding.
 255 /// There are at least two issues that should be addressed: input format and the need for lookahead.
 256 ///
 257 /// Some formats (like MPEG-1 ones) have fixed picture dimensions and framerate, or sampling rate.
 258 /// Some formats accept only pictures with dimensions being multiple of eight or sixteen.
 259 /// Some audio formats work only with monaural sound.
 260 /// 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.
 261 /// That is why `NAEncoder` has [`negotiate_format`] function that performs such check and returns what encoder can handle.
 262 ///
 263 /// 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.
 264 /// That is why encoder has two functions, one for queueing frames for encoding and one for obtaining encoded packets when they are available.
 265 /// 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.
 266 ///
 267 /// Overall encoding loop should look like this:
 268 /// ```ignore
 269 /// let encoder = ...; // create encoder
 270 /// let enc_params = encoder.negotiate_format(input_enc_params)?; // negotiate format
 271 /// let output_stream = encoder.init(stream_no, enc_params)?;
 272 /// while let Some(frame) = queue.get_frame() {
 273 ///     // convert to the format encoder expects if required
 274 ///     encoder.encode(frame)?;
 275 ///     while let Ok(enc_pkt) = encoder.get_packet()? {
 276 ///         // send encoded packet to a muxer for example
 277 ///     }
 278 /// }
 279 /// // retrieve the rest of encoded packets
 280 /// encoder.flush()?;
 281 /// while let Ok(enc_pkt) = encoder.get_packet()? {
 282 ///     // send encoded packet to a muxer for example
 283 /// }
 284 /// ```
 285 ///
 286 /// [`negotiate_format`]: ./trait.NAEncoder.html#tymethod.negotiate_format
 287 /// [`encode`]: ./trait.NAEncoder.html#tymethod.encode
 288 /// [`get_packet`]: ./trait.NAEncoder.html#tymethod.get_packet
 289 pub trait NAEncoder: NAOptionHandler {
 290     /// Tries to negotiate input format.
 291     ///
 292     /// This function takes input encoding parameters and returns adjusted encoding parameters if input ones make sense.
 293     /// If input parameters are empty then the default parameters are returned.
 294     ///
 295     /// # Example
 296     /// ```ignore
 297     /// let enc_params = [ EncodeParameters {...}, ..., EncodeParameters::default() ];
 298     /// let mut target_params = EncodeParameters::default();
 299     /// for params in enc_params.iter() {
 300     ///     if let Ok(dparams) = encoder.negotiate_format(params) {
 301     ///         target_params = dparams;
 302     ///         break;
 303     ///     }
 304     /// }
 305     /// // since negotiate_format(EncodeParameters::default()) will return a valid format, target_params should be valid here
 306     /// let stream = encoder.init(stream_id, target_params)?;
 307     /// // convert input into format defined in target_params, feed to the encoder, ...
 308     /// ```
 309     fn negotiate_format(&self, encinfo: &EncodeParameters) -> EncoderResult<EncodeParameters>;
 310     /// Queries encoder capabilities.
 311     ///
 312     /// See `ENC_CAPS_*` for examples.
 313     fn get_capabilities(&self) -> u64;
 314     /// Initialises the encoder.
 315     fn init(&mut self, stream_id: u32, encinfo: EncodeParameters) -> EncoderResult<NAStreamRef>;
 316     /// Takes a single frame for encoding.
 317     fn encode(&mut self, frm: &NAFrame) -> EncoderResult<()>;
 318     /// Returns encoded packet if available.
 319     fn get_packet(&mut self) -> EncoderResult<Option<NAPacket>>;
 320     /// Tells encoder to encode all data it currently has.
 321     fn flush(&mut self) -> EncoderResult<()>;
 322 }
 323
 324 /// Encoder information used during creating an encoder for requested codec.
 325 #[derive(Clone,Copy)]
 326 pub struct EncoderInfo {
 327     /// Short encoder name.
 328     pub name: &'static str,
 329     /// The function that creates an encoder instance.
 330     pub get_encoder: fn () -> Box<dyn NAEncoder + Send>,
 331 }
 332
 333 /// Structure for registering known encoders.
 334 ///
 335 /// 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.
 336 #[derive(Default)]
 337 pub struct RegisteredEncoders {
 338     encs:   Vec<EncoderInfo>,
 339 }
 340
 341 impl RegisteredEncoders {
 342     /// Constructs a new instance of `RegisteredEncoders`.
 343     pub fn new() -> Self {
 344         Self { encs: Vec::new() }
 345     }
 346     /// Adds another encoder to the registry.
 347     pub fn add_encoder(&mut self, enc: EncoderInfo) {
 348         self.encs.push(enc);
 349     }
 350     /// Searches for the encoder for the provided name and returns a function for creating it on success.
 351     pub fn find_encoder(&self, name: &str) -> Option<fn () -> Box<dyn NAEncoder + Send>> {
 352         for &enc in self.encs.iter() {
 353             if enc.name == name {
 354                 return Some(enc.get_encoder);
 355             }
 356         }
 357         None
 358     }
 359     /// Provides an iterator over currently registered encoders.
 360     pub fn iter(&self) -> std::slice::Iter<EncoderInfo> {
 361         self.encs.iter()
 362     }
 363 }
 364
 365 /// Trait for packetisers (objects that form full packets from raw stream data).
 366 pub trait NAPacketiser {
 367     /// Queues new raw stream data for parsing.
 368     ///
 369     /// Returns false is the internal buffer grows too large.
 370     fn add_data(&mut self, src: &[u8]) -> bool;
 371     /// Tries to retrieve stream information from the data.
 372     ///
 373     /// Returns [`NAStream`] reference on success (with stream ID set to `id`), [`ShortData`] when there is not enough data to parse the headers and other errors in case there was an error parsing the data.
 374     ///
 375     /// [`NAStream`]: ../frame/struct.NAStream.html
 376     /// [`ShortData`]: ./enum.DecoderError.html#variant.ShortData
 377     fn parse_stream(&mut self, id: u32) -> DecoderResult<NAStreamRef>;
 378     /// Tries to discard junk data until the first possible packet header.
 379     ///
 380     /// Returns the number of bytes skipped.
 381     fn skip_junk(&mut self) -> DecoderResult<usize>;
 382     /// Tries to form full packet from the already queued data.
 383     ///
 384     /// The function should be called repeatedly until it returns nothing or an error.
 385     fn get_packet(&mut self, stream: NAStreamRef) -> DecoderResult<Option<NAPacket>>;
 386     /// Resets the internal buffer.
 387     fn reset(&mut self);
 388     /// Tells how much data is left in the internal buffer.
 389     fn bytes_left(&self) -> usize;
 390 }
 391
 392 /// Decoder information used during creating a packetiser for requested codec.
 393 #[derive(Clone,Copy)]
 394 pub struct PacketiserInfo {
 395     /// Short packetiser name.
 396     pub name: &'static str,
 397     /// The function that creates a packetiser instance.
 398     pub get_packetiser: fn () -> Box<dyn NAPacketiser + Send>,
 399 }
 400
 401 /// Structure for registering known packetisers.
 402 ///
 403 /// It is supposed to be filled using `register_all_packetisers()` from some decoders crate and then it can be used to create packetisers for the requested codecs.
 404 #[derive(Default)]
 405 pub struct RegisteredPacketisers {
 406     packs:  Vec<PacketiserInfo>,
 407 }
 408
 409 impl RegisteredPacketisers {
 410     /// Constructs a new instance of `RegisteredPacketisers`.
 411     pub fn new() -> Self {
 412         Self { packs: Vec::new() }
 413     }
 414     /// Adds another packetiser to the registry.
 415     pub fn add_packetiser(&mut self, pack: PacketiserInfo) {
 416         self.packs.push(pack);
 417     }
 418     /// Searches for the packetiser for the provided name and returns a function for creating it on success.
 419     pub fn find_packetiser(&self, name: &str) -> Option<fn () -> Box<dyn NAPacketiser + Send>> {
 420         for &pack in self.packs.iter() {
 421             if pack.name == name {
 422                 return Some(pack.get_packetiser);
 423             }
 424         }
 425         None
 426     }
 427     /// Provides an iterator over currently registered packetiser.
 428     pub fn iter(&self) -> std::slice::Iter<PacketiserInfo> {
 429         self.packs.iter()
 430     }
 431 }
 432