drewnoakes/metadata-extractor

Identify thumbnail offset and length tags by name

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#263 创建于 2017年3月31日

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 (0 评论) (0 反应) (0 负责人)Java (2,411 star) (470 fork)batch import
bugformat-exifhelp wanted

描述

After recent changes, these two tags are displayed as unknown.

(From #262):

[Exif SubIFD] - New Subfile Type = Reduced-resolution image
[Exif SubIFD] - Compression = JPEG (old-style)
[Exif SubIFD] - X Resolution = 300 dots per inch
[Exif SubIFD] - Y Resolution = 300 dots per inch
[Exif SubIFD] - Resolution Unit = Inch
[Exif SubIFD] - Unknown tag (0x0201) = 1080832
[Exif SubIFD] - Unknown tag (0x0202) = 1737279
[Exif SubIFD] - YCbCr Positioning = Datum point

0x0201 is thumbnail offset, and 0x0202 is thumbnail length.

贡献者指南

技术栈
java
领域
toolingdata
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
2
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
1-3 hours
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
fresh
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
JavaExif metadata
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
80
研究方向
The issue references specific unknown tags 0x0201 (thumbnail offset) and 0x0202 (thumbnail length) in Exif SubIFD. Review the Exif tag definitions in the metadata extractor codebase, likely in a file like ExifDirectoryBase.java or similar. Add mapping for these two tags with appropriate names. Search for existing tag constants to follow the pattern. No additional comments or PRs are linked, so the implementation is straightforward once the correct location is found.