⎗ video/mp4

File Extensions

mp4, mp4v, mpg4

Magic Bytes

1. ISOBMFF file type box code + major brand prefix for MP4 base media

   Offset	4	5	6	7	8	9	10
   Byte	0x66	0x74	0x79	0x70	0x69	0x73	0x6f
   Char	f	t	y	p	i	s	o

2. ISOBMFF file type box code + major brand prefix for MP4 v1 or v2

   Offset	4	5	6	7	8	9	10
   Byte	0x66	0x74	0x79	0x70	0x6d	0x70	0x34
   Char	f	t	y	p	m	p	4

3. ISOBMFF file type box code + major brand prefix for MP4 with AVC extension

   Offset	4	5	6	7	8	9	10	11
   Byte	0x66	0x74	0x79	0x70	0x61	0x76	0x63	0x31
   Char	f	t	y	p	a	v	c	1

References

• Media Type Assignment
• RFC 4337 - MP4 File
• Apache HTTP MIME Types
• ISOBMFF Major Brand Designations
• MP4RA Brands