movii
6/29/2017 - 12:01 PM

笔记：使用 JavaScript 读取 JPEG 文件 EXIF 中的 Orientation - 1. Brife on JPEG

笔记：使用 JavaScript 读取 JPEG 文件 EXIF 中的 Orientation - 1. Brife on JPEG

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>> JPEG file structure:
+------+-----------------+---------------------------+
| Name |      Marker     |            Desc           |
+------+-----------------+---------------------------+
|  SOI |      0xFFD8     |       start of image      |
+------+-----------------+---------------------------+
| APP0 |      0xFFE0     |  JFIF application segment |
+------+-----------------+---------------------------+
| APP1 |      0xFFE1     |  Exif application segment |
+------+-----------------+---------------------------+
| APP2 |      0xFFE2     |  ICC application segment  |
+------+-----------------+---------------------------+
| APPn | 0xFFE1 ~ 0xFFEF | other application segment |
+------+-----------------+---------------------------+
|  COM |      0xFFFE     |          comment          |
+------+-----------------+---------------------------+
|  DQT |      0xFFDB     |     Quantization table    |
+------+-----------------+---------------------------+
| SOF0 |      0xFFC0     |      Start DCT frame      |
+------+-----------------+---------------------------+
|  DHT |      0xFFC4     |      Huffman table(s)     |
+------+-----------------+---------------------------+
|  SOS |      0xFFDA     |       Start of scan       |
+------+-----------------+---------------------------+
|  EOI |      0xFFD9     |        End of image       |
+------+-----------------+---------------------------+