NXV

• Extension: nxv
• Samples: tbd

NXV is a container format used by the "Brando MP4 Watch" product. The wrist watch is reported to support MP4, WMV and WMA, however this is achieved by first converting the files to the NXV format.

Container Format

 bytes  0-11   ASCIIZ  magic ("NXV File")
 bytes 16-19   ASCIIZ  version ("1.0.0", "3.0.1" or "3.0.2")
 byte     20   width (pixels)
 byte     21   height (pixels)
 byte  22-23   unknown (little endian)
 byte  24-511  rand byte
 (The a/v sequence commences at byte 512.)
 while eof
   u8[0x7fc]      audio payload
   le16           length (bytes)
   le16           unknown
   u8[length]     video payload

Audio Payload

The audio payload is an MP3 stream, including RIFF WAVE headers.

Video Payload

Raw video. 0.5 bits per pixel.

Notes

• The version number appears to have no influence on the container file format.
• Supported video resolutions are: 96x64, 96x80, 96x96, 128x96, 128x128, 160x128, 176x128. Despite the reduction in video resolution, the resulting NXV file size exceeds that of the input video file.
• Intermediate files are used by the NxvConverter program to store the audio and video payloads (filename.mp3 and filename.tmp) prior to muxing to the NXV file.

External Links

• Brando MP4 Watch Product Page
• Related doom9 thread