Module chunk 

RTMP chunk stream codec

RTMP messages are split into chunks for multiplexing. Each chunk has a header that identifies the chunk stream and message being sent.

Chunk Format:
+-------------+----------------+-------------------+
| Basic Header| Message Header | Chunk Data        |
| (1-3 bytes) | (0,3,7,11 bytes)| (variable)       |
+-------------+----------------+-------------------+

Basic Header formats:
- 1 byte:  fmt(2) + csid(6)        for csid 2-63
- 2 bytes: fmt(2) + 0 + csid(8)    for csid 64-319
- 3 bytes: fmt(2) + 1 + csid(16)   for csid 64-65599

Message Header formats (based on fmt):
- Type 0 (11 bytes): timestamp(3) + length(3) + type(1) + stream_id(4)
- Type 1 (7 bytes):  timestamp_delta(3) + length(3) + type(1)
- Type 2 (3 bytes):  timestamp_delta(3)
- Type 3 (0 bytes):  (use previous chunk's values)

Extended timestamp (4 bytes) is appended when timestamp >= 0xFFFFFF

Reference: RTMP Specification Section 5.3

Structs

ChunkDecoder

Chunk stream decoder

ChunkEncoder

Chunk stream encoder

RtmpChunk

A complete RTMP message (reassembled from chunks)