Codec type indication for immersive stereo content

For HTTP Live Streaming streams containing Dolby AC-4 tracks with immersive stereo content, the CODEC attribute of the EXT-X-STREAM-INF parameter follows the same requirements for regular Dolby AC-4 content. In addition, a CHANNELS attribute must be included in the #EXT-XMEDIA parameter.

The CHANNELS attribute must contain an IMSA identifier to indicate immersive stereo content. For immersive stereo content other than Dolby Atmos, the value of the CHANNELS attribute is 2/IMSA; for Dolby Atmos immersive stereo content, the recommended value of the CHANNELS attribute is 2/IMSA,ATMOS.

For example, for a media presentation containing a Dolby AC-4 bitstream with immersive stereo content, the CHANNELS attribute of the #EXT-X-MEDIA parameter must include the IMSA identifier.

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="ac4_IMS",NAME="English",LANGUAGE="en",DEFAULT=YES,AUTOSELECT=YES,
CHANNELS="2/IMSA",URI="audio_ims_index.m3u8"