jpeg 3.3 KB

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  1. #------------------------------------------------------------------------------
  2. # $File: jpeg,v 1.25 2015/01/02 16:56:50 christos Exp $
  3. # JPEG images
  4. # SunOS 5.5.1 had
  5. #
  6. # 0 string \377\330\377\340 JPEG file
  7. # 0 string \377\330\377\356 JPG file
  8. #
  9. # both of which turn into "JPEG image data" here.
  10. #
  11. 0 beshort 0xffd8 JPEG image data
  12. !:mime image/jpeg
  13. !:apple 8BIMJPEG
  14. !:strength +2
  15. >6 string JFIF \b, JFIF standard
  16. # The following added by Erik Rossen <rossen@freesurf.ch> 1999-09-06
  17. # in a vain attempt to add image size reporting for JFIF. Note that these
  18. # tests are not fool-proof since some perfectly valid JPEGs are currently
  19. # impossible to specify in magic(4) format.
  20. # First, a little JFIF version info:
  21. >>11 byte x \b %d.
  22. >>12 byte x \b%02d
  23. # Next, the resolution or aspect ratio of the image:
  24. >>13 byte 0 \b, aspect ratio
  25. >>13 byte 1 \b, resolution (DPI)
  26. >>13 byte 2 \b, resolution (DPCM)
  27. >>14 beshort x \b, density %dx
  28. >>16 beshort x \b%d
  29. >>4 beshort x \b, segment length %d
  30. # Next, show thumbnail info, if it exists:
  31. >>18 byte !0 \b, thumbnail %dx
  32. >>>19 byte x \b%d
  33. >6 string Exif \b, Exif standard: [
  34. >>12 indirect/r x
  35. >>12 string x \b]
  36. # Jump to the first segment
  37. >(4.S+4) use jpeg_segment
  38. # This uses recursion...
  39. 0 name jpeg_segment
  40. >0 beshort 0xFFFE
  41. # Recursion handled by FFE0
  42. #>>(2.S+2) use jpeg_segment
  43. >>2 pstring/HJ x \b, comment: "%s"
  44. >0 beshort 0xFFC0
  45. >>(2.S+2) use jpeg_segment
  46. >>4 byte x \b, baseline, precision %d
  47. >>7 beshort x \b, %dx
  48. >>5 beshort x \b%d
  49. >>9 byte x \b, frames %d
  50. >0 beshort 0xFFC1
  51. >>(2.S+2) use jpeg_segment
  52. >>4 byte x \b, extended sequential, precision %d
  53. >>7 beshort x \b, %dx
  54. >>5 beshort x \b%d
  55. >>9 byte x \b, frames %d
  56. >0 beshort 0xFFC2
  57. >>(2.S+2) use jpeg_segment
  58. >>4 byte x \b, progressive, precision %d
  59. >>7 beshort x \b, %dx
  60. >>5 beshort x \b%d
  61. >>9 byte x \b, frames %d
  62. # Define Huffman Tables
  63. >0 beshort 0xFFC4
  64. >>(2.S+2) use jpeg_segment
  65. >0 beshort 0xFFE1
  66. # Recursion handled by FFE0
  67. #>>(2.S+2) use jpeg_segment
  68. >>4 string Exif \b, Exif Standard: [
  69. >>>10 indirect/r x
  70. >>>10 string x \b]
  71. # Application specific markers
  72. >0 beshort&0xFFE0 =0xFFE0
  73. >>(2.S+2) use jpeg_segment
  74. # DB: Define Quantization tables
  75. # DD: Define Restart interval [XXX: wrong here, it is 4 bytes]
  76. # D8: Start of image
  77. # D9: End of image
  78. # Dn: Restart
  79. >0 beshort&0xFFD0 =0xFFD0
  80. >>0 beshort&0xFFE0 !0xFFE0
  81. >>>(2.S+2) use jpeg_segment
  82. #>0 beshort x unknown 0x%x
  83. #>>(2.S+2) use jpeg_segment
  84. # HSI is Handmade Software's proprietary JPEG encoding scheme
  85. 0 string hsi1 JPEG image data, HSI proprietary
  86. # From: David Santinoli <david@santinoli.com>
  87. 0 string \x00\x00\x00\x0C\x6A\x50\x20\x20\x0D\x0A\x87\x0A JPEG 2000
  88. # From: Johan van der Knijff <johan.vanderknijff@kb.nl>
  89. # Added sub-entries for JP2, JPX, JPM and MJ2 formats; added mimetypes
  90. # https://github.com/bitsgalore/jp2kMagic
  91. #
  92. # Now read value of 'Brand' field, which yields a few possibilities:
  93. >20 string \x6a\x70\x32\x20 Part 1 (JP2)
  94. !:mime image/jp2
  95. >20 string \x6a\x70\x78\x20 Part 2 (JPX)
  96. !:mime image/jpx
  97. >20 string \x6a\x70\x6d\x20 Part 6 (JPM)
  98. !:mime image/jpm
  99. >20 string \x6d\x6a\x70\x32 Part 3 (MJ2)
  100. !:mime video/mj2
  101. # Type: JPEG 2000 codesream
  102. # From: Mathieu Malaterre <mathieu.malaterre@gmail.com>
  103. 0 belong 0xff4fff51 JPEG 2000 codestream
  104. 45 beshort 0xff52