Description
PDFs may contain multimedia content: movies, sound and 3D content.
Risks
Rendering of multimedia content may depend on external applications that may not
be available in the future; the format in which multimedia content is stored may become obsolete.
Assessment
The following table shows the relevant output of Apache Preflight (part of Apache PDFBox) for PDFs that contain multimedia. Results obtained with Preflight 2.0.0:
| Reference file | Description | Error Code(s) | Details |
embedded_video_avi.pdf |
Contains embedded AVI movie | 5.2.1; 1.2.9 | Forbidden field in an annotation definition, The subtype isn't authorized : Screen; Body Syntax error, EmbeddedFile entry is present in a FileSpecification dictionary |
| embedded_video_quicktime.pdf |
Contains embedded Quicktime movie | 5.2.1; 1.2.9 | Forbidden field in an annotation definition, The subtype isn't authorized : Screen; Body Syntax error, EmbeddedFile entry is present in a FileSpecification dictionary |
| 20020402_CALOS.pdf |
From Multimedia & 3D Tests on Adobe Acrobat Engineering website | 5.2.1; 6.2.5 | Forbidden field in an annotation definition, The subtype isn't authorized : Movie; Action is forbidden, The action Movie is forbidden |
| Jpeg_linked.pdf |
From Multimedia & 3D Tests on Adobe Acrobat Engineering website | 5.2.1 | Forbidden field in an annotation definition, The subtype isn't authorized : Screen |
| MultiMedia_Acro6.pdf |
From Multimedia & 3D Tests on Adobe Acrobat Engineering website | 5.2.1 | Forbidden field in an annotation definition, The subtype isn't authorized : Screen |
| VolvoS40V50-Full.pdf |
From Multimedia & 3D Tests on Adobe Acrobat Engineering website | 6.2.6 | Action is forbidden, The action Rendition is undefined |
| movie.pdf |
From Multimedia & 3D Tests on Adobe Acrobat Engineering website | 5.2.1 | Forbidden field in an annotation definition, The subtype isn't authorized : Movie |
| AdobeChassisDemo-commented.pdf |
From Multimedia & 3D Tests on Adobe Acrobat Engineering website | 5.2.1 | Forbidden field in an annotation definition, The subtype isn't authorized : 3D |
Notes
Error codes generic, full error descriptions important as well
The Preflight source code reveals that some of the errors codes such as 5.2.1 and 6.2.5 are generic for annotation and action types that are forbidden in PDF/A-1. The Screen and Movie annotations are just two of them, which means that it is not possible to identify embedded movies without taking into account the elaborate error description (i.e. the contents of the details field in the output) as well.
Other multimedia annotations
Screen, Movie and 3D annotations are not the only multimedia annotations in PDF. The format specification distinguishes the following multimedia annotations:
- Movie annotations (predecessor of Screen annotations, deprecated since PDF 1.5)
- Screen annotations
- Sound annotations
- 3D annotations (3D objects, since PDF 1.6)
So in general any profiling for audiovisual multimedia content should include Movie, Screen and Sound annotations (and/or their corresponding Actions).
Additional test results
Results of additional tests with more complex PDFs with multimedia can be found here:
Analysis of Acrobat Engineering PDFs with Acrobat Preflight and Apache Preflight
Recommendations
Pre-ingest
- Formulate policy on how to deal with multimedia content in PDF, and its long-term accessibility requirements.
- Use Apache Preflight to establish if files contain multimedia content.
- For long-term accessibility of the embedded multimedia content, a possible option would be to extract the content to a file (movie, sound) before ingest, and ingest it as a supplementary file object to the PDF.
Existing collections
- Use Apache Preflight to establish if files contain multimedia content.
- For long-term accessibility of the embedded multimedia content, a possible option would be to extract the content to a file (movie, sound), and add it as a supplementary file object to the source PDF.
Example files
- http://www.opf-labs.org/format-corpus/pdfCabinetOfHorrors/ - PDF Cabinet of Horrors on OPF Format Corpus
- http://acroeng.adobe.com/wp/?page_id=61 - Multimedia & 3D Tests on the Adobe Acrobat Engineering website