The rocDecode VideoDemuxer utility class

The rocDecode FFMpeg demuxer utility class, VideoDemuxer, is used to demultiplex (demux) frames that can then be consumed by the FFMpeg decoder or the hardware decoder.

The VideoDemuxer() constructor takes either a file path or a StreamProvider object. The StreamProvider class is an abstract class that feeds a stream of packets to the demuxer. The StreamProvider GetData() and GetBufferSize() functions must be implemented to use a StreamProvider.

The VideoDemuxer Demux() function extracts the next video packet from the stream, and returns a pointer to the packet data, the packet size, and optionally the presentation timestamp.

Demux() demuxes frames sequentially starting at the beginning of the stream. The seek() function is used to start demuxing from a different frame.

A VideoSeekContext is passed to seek(). The seek context that specifies a seek criteria and a seek mode. The seek criteria describes whether the demuxer needs to seek to a specific frame or seek to a specific timestamp. The seek mode indicates whether the demuxer should seek to the exact frame or to the previous keyframe.