This patch populates the third entry for HLS codec attribute using the
AAC profile.
The HLS specifications[1] require this value to be the Object Type ID as
referred to in table 1.3 of ISO/IEC 14496-3:2009[2].
The numerical constants in the code refer to these OTIs minus one, as
documented in commit 372597e[3], confirmed by comparing the values in the
code with the values in the table mentioned above.
Links:
1: https://datatracker.ietf.org/doc/html/rfc6381#section-3.3
2: https://csclub.uwaterloo.ca/~ehashman/ISO14496-3-2009.pdf
3: 372597e538
Changes in this version:
- Default value set to "mp4a.40.2" when profile is unknown for backward
compatibility.
Signed-off-by: Steven Liu <liuqi05@kuaishou.com>