What is multimedia programming?
Multimedia programming is the craft of writing software that handles digital media: audio, video, and graphics. A media player, a video editor, an image viewer, a voice chat application, and a game engine are all multimedia programs at heart. They read media files, decode the data inside them, process or transform that data, and present it on a screen or through speakers.
The field is usually described in three areas: audio processing, video processing, and graphics rendering. Each area has its own formats, algorithms, and libraries, but all three share the same basic pattern of reading, decoding, processing, and output.
How a media application is built
Most media applications move data through the same four stages. First, the program reads the media file from storage. Second, it decodes the file: compressed audio becomes a stream of PCM samples, and compressed video becomes a sequence of frames. Third, it may process the decoded data, for example filtering audio or resizing frames. Fourth, it renders or writes the result to a screen, speakers, or another file.
Each stage leans on specific knowledge. Audio decoding involves PCM, sample rates such as 44.1 kHz, and the Nyquist theorem. Video decoding involves codecs such as H.264 or AV1. Graphics work involves color spaces such as RGB and image formats such as PNG and JPEG. The topic sections of this site explain each of these in turn.
A sensible first project
A good first project is one that touches the whole pattern without being overwhelming: read a WAV file and draw a picture of its waveform as a color gradient. WAV files usually store uncompressed PCM samples, which makes them easy to read without a codec. The task is to open the file, read the samples, map their values to colors, and draw the result into an image.
A project like this introduces three skills at once: handling a real media file, working with basic audio concepts, and turning data into a picture. From there, the same project can grow: add a second channel, draw a spectrogram, or read a compressed format instead.
Tools and next steps
Start with a general-purpose language you are comfortable with; Python and C++ are both common choices in this field. Learn the basics of how audio and video are represented in computers, then study a media framework or library once the fundamentals feel solid. Frameworks such as GStreamer abstract away much of the complexity of playback and processing, and they are easier to appreciate after you understand what they are doing underneath.
Practice in small projects, one concept at a time. Most of the libraries used in this field are open source and free to use, and costs for other tools vary by market. As you progress, reading the source code of open-source projects is one of the fastest ways to learn how experienced developers structure real media software.