MGV

From MSX Game Library

MGV is a video format for MSXgl.

Format

Header

Offset Size Desc. Value
0x0000 3 Signature "MGV"
0x0003 1 Flag
7  6  5  4  3  2  1  0
│        │  └──┴──┴──┴── File format version (0-15)
│        └────────────── Segment size (0: 8 KB, 1: 16 KB)
└─────────────────────── Include video format data (4 bytes)
(0x0004) 1 Video format - Image
7  6  5  4  3  2  1  0
│  │  │        └──┴──┴── Screen mode (0-7)
│  │  └───────────────── Screen width (0: 256 px, 1: 512 px)
└──┴──────────────────── Bit per pixel (0: 1-bit, 1: 2-bit, 2: 4-bit, 3: 8-bit)

Screen mode:

  • 0: TEXT - Screen 0, width 40 & 80
  • 1: GM1 - Screen 1
  • 2: GM2 - Screen 2 & 4
  • 3: MC - Screen 3
  • 4: BITMAP - Screen 5 ~ 8
  • 5: YAE - Screen 10 (GM7 + YJK + YAE)
  • 6: YJK - Screen 12 (GM7 + YJK)
(0x0005) 1 Video format - Replay
7  6  5  4  3  2  1  0
│  │        └──┴──┴──┴── Frame skip (0-15)
│  └──────────────────── Loop (0: No, 1: Yes)
└─────────────────────── Frequency (0: 50 Hz, 1: 60 Hz)

At 50 Hz, a frame skip of 1 means 25 fps.
At 60 Hz, a frame skip of 5 means 10 fps.

(0x0006) 1 Video format - Width 1-256 (or 2-512 for Screen mode 6 and 7)
(0x0007) 1 Video format - Height 1-256

Commands

Cmd Options Desc.
00 End of data
01 End of segment (increment segment index and reset data pointer)
02 End of line
x3 Switch to table

x:

  • 0: Pattern table (default)
  • 1: Color table (screen mode 1, 2 and 3)
  • 2: Layout table (tile based modes)
  • 3: Color palette (MSX2/2+)
n4 Skip n bytes (1-15)
05 nn Skip nn bytes (1-255)
06 nnnn Skip nnnn bytes (1-65535)
07 Skip a frame / End of frame
n8 vv Fill n bytes (1-15) with vv value
09 nn,vv Fill nn bytes (1-255) with vv value
0A nnnn,vv Fill nnnn bytes (1-65535) with vv value
0B vv Fill a full frame with vv value
nC vv[n] Copy n bytes (1-15) from vv[n] data table
0D nn,vv[nn] Copy nn bytes (1-255) from vv[nn] data table
0E nnnn,vv[nnnn] Copy nnnn bytes (1-65535) from vv[nnnn] data table
0F vv[] Copy a full frame from data table (raw frame)

Extension

  • Default extension (for MSX-DOS): .MGV
  • Alternative for Windows/Linux: .MGLV

Change log

  • Version 1.0 (2024/03/31)
    • Original version (File format version 0)