Module toy 

Reference implementations: a toy container (TIVF: a 20-byte header and length-prefixed timed packets) and a toy codec (a packet holds 0..3 grey pictures and may re-present the previous one).

They exercise every rule of the media contracts: output later than input and 0..N frames per packet, shared pictures, backpressure, drain, reset, configuration epochs, seeking with an index scan, and pulled muxer output with or without patches. The conformance checks are validated against them, as zencodec-testkit’s checks are against its reference codec.

TIVF header: b"TIVF", width u16, height u16, time base numerator u32, denominator u32, packet count u32 (0 = unknown), all little endian. Packet: payload length u32, pts i64, flags u8 (bit 0: random access), payload. Toy payload: picture count u8 (0..=3), show-existing u8, then the grey planes.

Structs

ToyDecoder

Toy decoder. Pictures come out one packet late (a one-packet reorder), so output trails input; a show-existing flag re-presents the previous picture. Holds at most max_queued_frames before pushing back.

ToyDemuxer

Sans-I/O TIVF demuxer. Sequential by default; seek builds a bounded index by scanning packet headers with Range requests.

ToyEncoder

Toy encoder: one gray picture per packet, lookahead frames held back, a random-access point every keyint packets.

ToyMuxer

TIVF muxer. write_count means the header’s packet count is patched at finish, which a forward-only destination cannot accept.

Enums

ToyError

Errors of the toy container and codec.

Constants

HEADER_LEN

TIVF header length.

MAGIC

The TIVF file signature.

PACKET_HEADER_LEN

TIVF packet header length.

Functions

toy_payload

Build a toy packet payload.