Compression Options
Being a container many encoding options are present for Matroska: H264, HVEC H265 and VP9, as well as the option to copy 1:1 (re-mux) an existing format (such as h264 in a .mp4 file) which copies video and audio without encoding.
A quality slider chooses encoding quality, or bit rate, a drop combo below the slider offers 4 types of encoding (depending on encoder chosen):
- Constant Bit Rate a fixed bit rate is used through out encoding,
- Average Bit Rate like Constant Bit Rate except there is some encoding flexibility, for difficult parts a higher bit rate is used, overall though the bit rate averages out to the requested value,
- Constant Quality a desired quality is achieved throughout the encoding process, by varying bit rate, this is the recommended mode for most people.
- Lossless encodes video without loss of quality, expect end files to be large, test to ensure compatibility with various players.
Advanced options page offers Tuning for specific video types.
GPU Encoding
In addition to software encoders, there is the choice of using a GPU encoder (should a compatible graphics card be installed), with selections for Nvidia, Intel QSV and AMD.
Hardware encoders typically will have less options, and have less quality than a software encoder, however they encode many times faster.
If using a GPU encoder, combine with the DSP effect 'GPU Accelerated Decoding'.
Audio
A multitude of audio formats are available to be chosen, with the option also to copy 1:1 from source if the audio is already in a correct format.
If re-encoding audio, on the advanced page is an option to normalize volume.