Why do some files fail to transcode?

File transcoding failure may have the following reasons:

• The source file is not editable. The source file to be transcoded must be editable. Transcoding is not supported for files that are "read-only", "binary encrypted", or have other protections that prevent content from being edited.
• The images contained in the file are damaged during compression, destroying the image structure. In this case, although the image can be previewed normally, it will cause file transcoding to fail.

For example: if an image is imported normally in Microsoft Office PPT but cannot be converted to PDF, you can determine the failure reason and handle it through the following steps:

1. Use an image processing tool to determine if the image is corrupted: for example, if using PS tool to import the image results in an error "IDAT: incorrect data check", it means the image is corrupted;
2. Use Microsoft Office PPT to "Save As" the image. PPT will reprocess the image. At this time, re-insert the saved image into the source file, and file transcoding can proceed normally.