mpeg-pes 0.7.0

PES (Packetized Elementary Stream) depacketization + PTS/DTS — ISO/IEC 13818-1 §2.4.3.
Documentation 
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//! `stream_id` — identifies the elementary stream a PES packet belongs to
//! (ISO/IEC 13818-1 Table 2-22). Certain values carry no optional PES header.

/// 8-bit `stream_id` of a PES packet.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[cfg_attr(feature = "serde", derive(serde::Serialize))]
pub struct StreamId(pub u8);

// Special stream_ids that do NOT carry the optional PES header (the bytes after
// PES_packet_length are the payload directly) — ISO/IEC 13818-1 §2.4.3.6.
const PROGRAM_STREAM_MAP: u8 = 0xBC;
const PADDING_STREAM: u8 = 0xBE;
const PRIVATE_STREAM_2: u8 = 0xBF;
const ECM_STREAM: u8 = 0xF0;
const EMM_STREAM: u8 = 0xF1;
const DSMCC_STREAM: u8 = 0xF2;
const H222_1_TYPE_E: u8 = 0xF8;
const EXTENDED_STREAM_ID: u8 = 0xFD;
const PROGRAM_STREAM_DIRECTORY: u8 = 0xFF;

// ORDER: `stream_id_extension` values are a separate namespace from the `stream_id` constants above; ascending among themselves.
/// `stream_id_extension` of an AVS3 video PES (T/AI 109.6, as cited by ETSI TS
/// 101 154 V2.10.1 section 4.1.8 "Encoding"): the PES uses `stream_id = 0xFD`
/// ([`StreamId::EXTENDED_STREAM_ID`]) and this extension value.
pub const STREAM_ID_EXTENSION_AVS3_VIDEO: u8 = 0x41;
/// `stream_id_extension` of an AVS3-P3 audio PES: binary `100 1111` (T/AI 109.7
/// clause 8.1.2, ETSI TS 101 154 V2.10.1 section 4.1.8.35), with
/// `stream_id = 0xFD` and `stream_id_extension_flag = 0`.
pub const STREAM_ID_EXTENSION_AVS3_AUDIO: u8 = 0b100_1111;

impl StreamId {
    /// `program_stream_map` (0xBC).
    pub const PROGRAM_STREAM_MAP: StreamId = StreamId(PROGRAM_STREAM_MAP);
    /// `padding_stream` (0xBE).
    pub const PADDING_STREAM: StreamId = StreamId(PADDING_STREAM);
    /// `private_stream_2` (0xBF).
    pub const PRIVATE_STREAM_2: StreamId = StreamId(PRIVATE_STREAM_2);
    /// `extended_stream_id` (0xFD, ISO/IEC 13818-1 Table 2-22): the real stream
    /// is identified by the `stream_id_extension` in the PES extension field.
    pub const EXTENDED_STREAM_ID: StreamId = StreamId(EXTENDED_STREAM_ID);

    /// True if this `stream_id` carries the optional PES header (flags +
    /// `PES_header_data_length` + PTS/DTS). False for the special streams whose
    /// `PES_packet_data_byte`s follow `PES_packet_length` directly.
    #[must_use]
    pub const fn has_optional_header(self) -> bool {
        !matches!(
            self.0,
            PROGRAM_STREAM_MAP
                | PADDING_STREAM
                | PRIVATE_STREAM_2
                | ECM_STREAM
                | EMM_STREAM
                | DSMCC_STREAM
                | H222_1_TYPE_E
                | PROGRAM_STREAM_DIRECTORY
        )
    }

    /// True for an audio stream (`110x xxxx`, 0xC0–0xDF).
    #[must_use]
    pub const fn is_audio(self) -> bool {
        self.0 & 0xE0 == 0xC0
    }

    /// True for a video stream (`1110 xxxx`, 0xE0–0xEF).
    #[must_use]
    pub const fn is_video(self) -> bool {
        self.0 & 0xF0 == 0xE0
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn classification() {
        assert!(StreamId(0xC0).is_audio());
        assert!(StreamId(0xE0).is_video());
        assert!(StreamId(0xE0).has_optional_header());
        assert!(StreamId(0xBD).has_optional_header()); // private_stream_1 does
        assert!(!StreamId::PADDING_STREAM.has_optional_header());
        assert!(!StreamId::PROGRAM_STREAM_MAP.has_optional_header());
        assert!(!StreamId(0xFF).has_optional_header());
        // 0xFD extended_stream_id carries the optional header (and the extension).
        assert!(StreamId::EXTENDED_STREAM_ID.has_optional_header());
        assert_eq!(StreamId::EXTENDED_STREAM_ID, StreamId(0xFD));
        assert_eq!(STREAM_ID_EXTENSION_AVS3_VIDEO, 0x41);
        assert_eq!(STREAM_ID_EXTENSION_AVS3_AUDIO, 0x4F);
    }
}