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 /// Encoding parameters.
 214 #[derive(Clone,Copy,PartialEq)]
 215 pub struct EncodeParameters {
 216     /// Input format.
 217     pub format:     NACodecTypeInfo,
 218     /// Time base numerator. Ignored for audio.
 219     pub tb_num:     u32,
 220     /// Time base denominator. Ignored for audio.
 221     pub tb_den:     u32,
 222     /// Bitrate in kilobits per second.
 223     pub bitrate:    u32,
 224     /// A collection of various boolean encoder settings like CBR mode.
 225     ///
 226     /// See `ENC_MODE_*` constants for available options.
 227     pub flags:      u64,
 228     /// Encoding quality.
 229     pub quality:    u8,
 230 }
 231
 232 impl Default for EncodeParameters {
 233     fn default() -> EncodeParameters {
 234         EncodeParameters {
 235             format:     NACodecTypeInfo::None,
 236             tb_num:     0,
 237             tb_den:     0,
 238             bitrate:    0,
 239             flags:      0,
 240             quality:    0,
 241         }
 242     }
 243 }
 244
 245 /// Encoder trait.
 246 ///
 247 /// Overall encoding is more complex than decoding.
 248 /// There are at least two issues that should be addressed: input format and the need for lookahead.
 249 ///
 250 /// Some formats (like MPEG-1 ones) have fixed picture dimensions and framerate, or sampling rate.
 251 /// Some formats accept only pictures with dimensions being multiple of eight or sixteen.
 252 /// Some audio formats work only with monaural sound.
 253 /// 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.
 254 /// That is why `NAEncoder` has [`negotiate_format`] function that performs such check and returns what encoder can handle.
 255 ///
 256 /// 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.
 257 /// That is why encoder has two functions, one for queueing frames for encoding and one for obtaining encoded packets when they are available.
 258 /// 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.
 259 ///
 260 /// Overall encoding loop should look like this:
 261 /// ```ignore
 262 /// let encoder = ...; // create encoder
 263 /// let enc_params = encoder.negotiate_format(input_enc_params)?; // negotiate format
 264 /// let output_stream = encoder.init(stream_no, enc_params)?;
 265 /// while let Some(frame) = queue.get_frame() {
 266 ///     // convert to the format encoder expects if required
 267 ///     encoder.encode(frame)?;
 268 ///     while let Ok(enc_pkt) = encoder.get_packet()? {
 269 ///         // send encoded packet to a muxer for example
 270 ///     }
 271 /// }
 272 /// // retrieve the rest of encoded packets
 273 /// encoder.flush()?;
 274 /// while let Ok(enc_pkt) = encoder.get_packet()? {
 275 ///     // send encoded packet to a muxer for example
 276 /// }
 277 /// ```
 278 ///
 279 /// [`negotiate_format`]: ./trait.NAEncoder.html#tymethod.negotiate_format
 280 /// [`encode`]: ./trait.NAEncoder.html#tymethod.encode
 281 /// [`get_packet`]: ./trait.NAEncoder.html#tymethod.get_packet
 282 pub trait NAEncoder: NAOptionHandler {
 283     /// Tries to negotiate input format.
 284     ///
 285     /// This function takes input encoding parameters and returns adjusted encoding parameters if input ones make sense.
 286     /// If input parameters are empty then the default parameters are returned.
 287     ///
 288     /// # Example
 289     /// ```ignore
 290     /// let enc_params = [ EncodeParameters {...}, ..., EncodeParameters::default() ];
 291     /// let mut target_params = EncodeParameters::default();
 292     /// for params in enc_params.iter() {
 293     ///     if let Ok(dparams) = encoder.negotiate_format(params) {
 294     ///         target_params = dparams;
 295     ///         break;
 296     ///     }
 297     /// }
 298     /// // since negotiate_format(EncodeParameters::default()) will return a valid format, target_params should be valid here
 299     /// let stream = encoder.init(stream_id, target_params)?;
 300     /// // convert input into format defined in target_params, feed to the encoder, ...
 301     /// ```
 302     fn negotiate_format(&self, encinfo: &EncodeParameters) -> EncoderResult<EncodeParameters>;
 303     /// Initialises the encoder.
 304     fn init(&mut self, stream_id: u32, encinfo: EncodeParameters) -> EncoderResult<NAStreamRef>;
 305     /// Takes a single frame for encoding.
 306     fn encode(&mut self, frm: &NAFrame) -> EncoderResult<()>;
 307     /// Returns encoded packet if available.
 308     fn get_packet(&mut self) -> EncoderResult<Option<NAPacket>>;
 309     /// Tells encoder to encode all data it currently has.
 310     fn flush(&mut self) -> EncoderResult<()>;
 311 }
 312
 313 /// Encoder information used during creating an encoder for requested codec.
 314 #[derive(Clone,Copy)]
 315 pub struct EncoderInfo {
 316     /// Short encoder name.
 317     pub name: &'static str,
 318     /// The function that creates an encoder instance.
 319     pub get_encoder: fn () -> Box<dyn NAEncoder + Send>,
 320 }
 321
 322 /// Structure for registering known encoders.
 323 ///
 324 /// 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.
 325 #[derive(Default)]
 326 pub struct RegisteredEncoders {
 327     encs:   Vec<EncoderInfo>,
 328 }
 329
 330 impl RegisteredEncoders {
 331     /// Constructs a new instance of `RegisteredEncoders`.
 332     pub fn new() -> Self {
 333         Self { encs: Vec::new() }
 334     }
 335     /// Adds another encoder to the registry.
 336     pub fn add_encoder(&mut self, enc: EncoderInfo) {
 337         self.encs.push(enc);
 338     }
 339     /// Searches for the encoder for the provided name and returns a function for creating it on success.
 340     pub fn find_encoder(&self, name: &str) -> Option<fn () -> Box<dyn NAEncoder + Send>> {
 341         for &enc in self.encs.iter() {
 342             if enc.name == name {
 343                 return Some(enc.get_encoder);
 344             }
 345         }
 346         None
 347     }
 348     /// Provides an iterator over currently registered encoders.
 349     pub fn iter(&self) -> std::slice::Iter<EncoderInfo> {
 350         self.encs.iter()
 351     }
 352 }
 353
 354 /// Trait for packetisers (objects that form full packets from raw stream data).
 355 pub trait NAPacketiser {
 356     /// Queues new raw stream data for parsing.
 357     ///
 358     /// Returns false is the internal buffer grows too large.
 359     fn add_data(&mut self, src: &[u8]) -> bool;
 360     /// Tries to retrieve stream information from the data.
 361     ///
 362     /// 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.
 363     ///
 364     /// [`NAStream`]: ../frame/struct.NAStream.html
 365     /// [`ShortData`]: ./enum.DecoderError.html#variant.ShortData
 366     fn parse_stream(&mut self, id: u32) -> DecoderResult<NAStreamRef>;
 367     /// Tries to discard junk data until the first possible packet header.
 368     ///
 369     /// Returns the number of bytes skipped.
 370     fn skip_junk(&mut self) -> DecoderResult<usize>;
 371     /// Tries to form full packet from the already queued data.
 372     ///
 373     /// The function should be called repeatedly until it returns nothing or an error.
 374     fn get_packet(&mut self, stream: NAStreamRef) -> DecoderResult<Option<NAPacket>>;
 375     /// Resets the internal buffer.
 376     fn reset(&mut self);
 377 }
 378
 379 /// Decoder information used during creating a packetiser for requested codec.
 380 #[derive(Clone,Copy)]
 381 pub struct PacketiserInfo {
 382     /// Short packetiser name.
 383     pub name: &'static str,
 384     /// The function that creates a packetiser instance.
 385     pub get_packetiser: fn () -> Box<dyn NAPacketiser + Send>,
 386 }
 387
 388 /// Structure for registering known packetisers.
 389 ///
 390 /// 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.
 391 #[derive(Default)]
 392 pub struct RegisteredPacketisers {
 393     packs:  Vec<PacketiserInfo>,
 394 }
 395
 396 impl RegisteredPacketisers {
 397     /// Constructs a new instance of `RegisteredPacketisers`.
 398     pub fn new() -> Self {
 399         Self { packs: Vec::new() }
 400     }
 401     /// Adds another packetiser to the registry.
 402     pub fn add_packetiser(&mut self, pack: PacketiserInfo) {
 403         self.packs.push(pack);
 404     }
 405     /// Searches for the packetiser for the provided name and returns a function for creating it on success.
 406     pub fn find_packetiser(&self, name: &str) -> Option<fn () -> Box<dyn NAPacketiser + Send>> {
 407         for &pack in self.packs.iter() {
 408             if pack.name == name {
 409                 return Some(pack.get_packetiser);
 410             }
 411         }
 412         None
 413     }
 414     /// Provides an iterator over currently registered packetiser.
 415     pub fn iter(&self) -> std::slice::Iter<PacketiserInfo> {
 416         self.packs.iter()
 417     }
 418 }
 419