diff --git a/terranmon.txt b/terranmon.txt index d4550f3..f55afd9 100644 --- a/terranmon.txt +++ b/terranmon.txt @@ -1609,8 +1609,8 @@ TSVM Advanced Video - Digital Tape (TAV-DT) Format Created by CuriousTorvald on 2025-12-01 TAV-DT is an extension to TAV format that is intended as filesystem-independent packetised video stream -with easy syncing (playback can start from the arbitrary position and decoder can easily sync up to the -start of the packet) +with easy syncing: playback can start from the arbitrary position and decoder can easily sync up to the +start of the next packet # Video Format - Dimension: 720x480 for NTSC, 720x576 for PAL @@ -1633,7 +1633,7 @@ start of the packet) uint8 Flags - bit 0 = interlaced - bit 1 = is NTSC framerate - - bit 4-7 = quality index + - bit 4-7 = quality index (0-15) int16 Reserved (zero-fill) uint32 Total packet size past header uint32 CRC-32 of 12-byte header @@ -1641,6 +1641,34 @@ start of the packet) * TAD packet (full 0x24 packet) * TAV packet (full 0x10 or 0x12 packet) +# How to sync to the stream + 1. Find a sync pattern + 2. Read remaining 8 bytes -> concatenate sync with what has been read + 3. Calculate CRC-32 of concatenated 12 bytes + 4. Read 4 bytes (stored CRC) + 5. Check calculated CRC against stored CRC + 6. If they match, sync to the stream; if not, find a next sync pattern + +# Quality Indices + +QIndex | Y,Co,Cg (true value) | TAD quality (max index) +----------------------------------------- + 0 | 60,104,312 | 23 + 1 | 44,88,248 | 31 + 2 | 36,72,188 | 39 + 3 | 28,56,136 | 47 + 4 | 20,48,106 | 55 + 5 | 16,40,80 | 63 + 6 | 12,36,68 | 71 + 7 | 10,32,58 | 79 + 8 | 8,28,48 | 87 + 9 | 6,24,38 | 95 +10 | 5,20,30 | 103 +11 | 4,16,22 | 111 +12 | 3,12,16 | 119 +13 | 2,8,10 | 123 +14 | 2,5,6 | 127 +15 | 1,2,2 | 127 --------------------------------------------------------------------------------