| 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 | |
| 7 | /// A list specifying general decoding errors. |
| 8 | #[derive(Debug,Clone,Copy,PartialEq)] |
| 9 | #[allow(dead_code)] |
| 10 | pub enum DecoderError { |
| 11 | /// No frame was provided. |
| 12 | NoFrame, |
| 13 | /// Allocation failed. |
| 14 | AllocError, |
| 15 | /// Operation requires repeating. |
| 16 | TryAgain, |
| 17 | /// Invalid input data was provided. |
| 18 | InvalidData, |
| 19 | /// Provided input turned out to be incomplete. |
| 20 | ShortData, |
| 21 | /// Decoder could not decode provided frame because it references some missing previous frame. |
| 22 | MissingReference, |
| 23 | /// Feature is not implemented. |
| 24 | NotImplemented, |
| 25 | /// Some bug in decoder. It should not happen yet it might. |
| 26 | Bug, |
| 27 | } |
| 28 | |
| 29 | /// A specialised `Result` type for decoding operations. |
| 30 | pub type DecoderResult<T> = Result<T, DecoderError>; |
| 31 | |
| 32 | impl From<ByteIOError> for DecoderError { |
| 33 | fn from(_: ByteIOError) -> Self { DecoderError::ShortData } |
| 34 | } |
| 35 | |
| 36 | impl From<BitReaderError> for DecoderError { |
| 37 | fn from(e: BitReaderError) -> Self { |
| 38 | match e { |
| 39 | BitReaderError::BitstreamEnd => DecoderError::ShortData, |
| 40 | _ => DecoderError::InvalidData, |
| 41 | } |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | impl From<CodebookError> for DecoderError { |
| 46 | fn from(_: CodebookError) -> Self { DecoderError::InvalidData } |
| 47 | } |
| 48 | |
| 49 | impl From<AllocatorError> for DecoderError { |
| 50 | fn from(_: AllocatorError) -> Self { DecoderError::AllocError } |
| 51 | } |
| 52 | |
| 53 | /// Auxiliary structure for storing data used by decoder but also controlled by the caller. |
| 54 | pub struct NADecoderSupport { |
| 55 | /// Frame buffer pool for 8-bit or packed video frames. |
| 56 | pub pool_u8: NAVideoBufferPool<u8>, |
| 57 | /// Frame buffer pool for 16-bit video frames. |
| 58 | pub pool_u16: NAVideoBufferPool<u16>, |
| 59 | /// Frame buffer pool for 32-bit video frames. |
| 60 | pub pool_u32: NAVideoBufferPool<u32>, |
| 61 | } |
| 62 | |
| 63 | impl NADecoderSupport { |
| 64 | /// Constructs a new instance of `NADecoderSupport`. |
| 65 | pub fn new() -> Self { |
| 66 | Self { |
| 67 | pool_u8: NAVideoBufferPool::new(0), |
| 68 | pool_u16: NAVideoBufferPool::new(0), |
| 69 | pool_u32: NAVideoBufferPool::new(0), |
| 70 | } |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | impl Default for NADecoderSupport { |
| 75 | fn default() -> Self { Self::new() } |
| 76 | } |
| 77 | |
| 78 | /// Decoder trait. |
| 79 | pub trait NADecoder { |
| 80 | /// Initialises the decoder. |
| 81 | /// |
| 82 | /// It takes [`NADecoderSupport`] allocated by the caller and `NACodecInfoRef` provided by demuxer. |
| 83 | /// |
| 84 | /// [`NADecoderSupport`]: ./struct.NADecoderSupport.html |
| 85 | fn init(&mut self, supp: &mut NADecoderSupport, info: NACodecInfoRef) -> DecoderResult<()>; |
| 86 | /// Decodes a single frame. |
| 87 | fn decode(&mut self, supp: &mut NADecoderSupport, pkt: &NAPacket) -> DecoderResult<NAFrameRef>; |
| 88 | /// Tells decoder to clear internal state (e.g. after error or seeking). |
| 89 | fn flush(&mut self); |
| 90 | } |
| 91 | |
| 92 | /// Decoder information using during creating a decoder for requested codec. |
| 93 | #[derive(Clone,Copy)] |
| 94 | pub struct DecoderInfo { |
| 95 | /// Short decoder name. |
| 96 | pub name: &'static str, |
| 97 | /// The function that creates a decoder instance. |
| 98 | pub get_decoder: fn () -> Box<dyn NADecoder + Send>, |
| 99 | } |
| 100 | |
| 101 | /// Structure for registering known decoders. |
| 102 | /// |
| 103 | /// 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. |
| 104 | #[derive(Default)] |
| 105 | pub struct RegisteredDecoders { |
| 106 | decs: Vec<DecoderInfo>, |
| 107 | } |
| 108 | |
| 109 | impl RegisteredDecoders { |
| 110 | /// Constructs a new instance of `RegisteredDecoders`. |
| 111 | pub fn new() -> Self { |
| 112 | Self { decs: Vec::new() } |
| 113 | } |
| 114 | /// Adds another decoder to the registry. |
| 115 | pub fn add_decoder(&mut self, dec: DecoderInfo) { |
| 116 | self.decs.push(dec); |
| 117 | } |
| 118 | /// Searches for the decoder for the provided name and returns a function for creating it on success. |
| 119 | pub fn find_decoder(&self, name: &str) -> Option<fn () -> Box<dyn NADecoder + Send>> { |
| 120 | for &dec in self.decs.iter() { |
| 121 | if dec.name == name { |
| 122 | return Some(dec.get_decoder); |
| 123 | } |
| 124 | } |
| 125 | None |
| 126 | } |
| 127 | /// Provides an iterator over currently registered decoders. |
| 128 | pub fn iter(&self) -> std::slice::Iter<DecoderInfo> { |
| 129 | self.decs.iter() |
| 130 | } |
| 131 | } |