SMJPEG is a simple video codec first developped by Loki Software and supported by FFMpeg, VLC and by Antiryad Gx as an interchange video format.
This describe the file format and extensions.

All numbers are in big endian format.

• SMJPEG (6 bytes)
• Version (=0) (4 bytes)
• Video duration in milliseconds (4 bytes)

[Extended by FFMpeg]

• _TXT fourcc (4 bytes)
• Datas size (4 bytes)
• Text data

• _SND fourcc (4 bytes)
• Datas size (4 bytes)
• Samplerate (2 bytes)
• Bits per sample (1 bytes)
• Channels (1 bytes)
• Format fourcc: APCM or NONE (4 bytes)

• _VID fourcc (4 bytes)
• Datas size (4 bytes)
• Total frames (4 bytes)
• Width (2 bytes)
• Height (2 bytes)
• Format fourcc (4 bytes)

• HEND fourcc (4 bytes)

• sndD fourcc (4 bytes)
• Time in milliseconds (4 bytes)
• Datas size (4 bytes)
• Datas

• vidD fourcc (4 bytes)
• Time in milliseconds (4 bytes)
• Datas size (4 bytes)
• Datas

• DONE fourcc (4 bytes)