When a asset contains multiple cc embedded tracks, current Cea708Decoder service
block parsing logic is discarding all the data in that frame.
For example, a manifest with 2 embedded CEA-708 close captions tracks:
<Accessibility schemeIdUri="urn:scte:dash:cc:cea-708:2015" value="1=lang:eng;2=lang:spa"/>
when the spanish track is selected (service number 2), when processing the
following CEA-708 frame:
FC9420FD2062FF0829FE8CFCFE9818FEE332FE731FFE1042FE2062FE0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000FA0000
the frame can be descomposed as:
FF0829 FE8CFC FE9818 FEE332 FE731F FE1042 FE2062 FE0000
08 (00 001000) 0 (sequence) 8 (frame size)
298CFC9818E332731F10 422062 0000
=====
29 (001 01001) 1 (service number) 9 (service block length)
8CFC9818E332731F10
42 (010 00010) 2 (service number) 2 (service block length)
2062
0000 Null block service
The current processCurrentPacket logic will discard the whole frame is discarded
because the first service number found in the frame belongs to service number 1,
which is not the one we are currently looking for.
This commit modifies the processCurrentPacket decoding logic, to take into
account all service blocks available in the frame, by iteraring over the
full frame data and skipping those service blocks we are not interesting in.
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>
9ceba909da