Multi Channel Audio (MCA) is becoming increasingly popular for TV productions, especially when post-produced in HD. Many facilities use the Material eXchange Format (MXF) in their production workflow. This means the number of audio channels supported depends on the MXF profile used. But it is not the only factor determining how many audio tracks are available. Workflows may also be constraint by backwards compatibility requirements, e.g. the need to be able to write back material to the acquisition media originally used.
EBU R 134
The net result is that the number of tracks available to audio engineers can be much lower than what would be ideal, leading to complicated workarounds with the risk of losing valuable time, making mistakes and lowering quality.
The new EBU Recommendation R 134 - MXF and Multi Channel Audio (MCA) addresses this issue. The EBU recommends MXF production equipment to support at least 16 individual, uncompressed audio channels where possible, with the outlook to potentially extend this number to 32 or even 64 channels in the mid-term. Where content is transferred from a format with more audio channels than the target format, users should have the option to select which channels to transfer. Similarly equipment should tell the users which channels would be lost in a transcoding process.
EBU R 134 also provides an overview fo the number of audio channels and bit-depths currently supported in MXF acquisition devices (see the table ->). |
Expert Community on Audio
For more information on audio, join the EBU Expert Community on Audio (ECA) or contact: Roger Miles (EBU) .