Apps with 'Batch conversion' feature

HandBrake is an open-source, multithreaded video transcoder – it compresses and converts digital media from one format to another. HandBrake can rip encrypted DVDs with libdvdcss (libdvdcss is installed with VLC media player on macOS, or AnyDVD/DVD 43 on Windows).

Calibre is a free and open source e-book library management application made by users, for users. Many languages, designed around the concept of the logical book, i.e., a single entry in your library that may correspond to actual e-book files in several formats.

Fast and compact image viewer/converter trying to be simple for beginners and powerful for professionals. Many supported file formats and features.

XnViewMP is a free software to view, organise, convert graphics and photos files or to create slide show, contact sheet, HTML pages.

FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor. It has a nice array of features that include image viewing, management, comparison, red-eye removal, emailing, resizing, cropping and color adjustments.

A cross platform front-end GUI of the popular youtube-dl written in wxPython.

XnView is a utility for viewing and converting graphic files. XnView is provided as FREEWARE for private non-commercial or educational use (including non-profit organization).

Ocenaudio is a cross-platform, easy to use, fast and functional audio editor. It is the ideal software for people who need to edit and analyze audio files without complications. ocenaudio also has powerful features that will please more advanced users.

RawTherapee is a free RAW converter and digital photo processing software. All changes can be applied and batch processed at a convenient time.

XMedia Recode can convert nearly all popular audio and video formats including 3GP, 3GPP, 3GPP2, AAC, AC3, AMR, ASF, AVI, AVISynth, DVD, FLAC, FLV, H.261, H.263, H.

VidCoder is a DVD/Blu-ray ripping and video transcoding application for Windows. It uses HandBrake as its encoding engine.

Nitro Pro gives you everything you need to create, convert, edit, sign, and share 100% industry-standard PDF files. It's simple, straightforward, and intuitive to use — so you can work more productively, your way.

iLovePDF is an online service to work with PDF files completely free and easy to use. Merge PDF, split PDF, compress PDF, office to PDF, PDF to JPG and more!

AnvSoft Any Video Converter is the most renowned video converter for converting video files between various formats, with fast converting speed and excellent video quality.

Imagine is an Image & Animation Viewer for Windows with screen capture function.