fdkaacdec: Enable 8-channel playback
The decoder seems to default to 6 channels max, downmixing 7.1 to 5.1.
Disable the channel limit to expose all channels to GStreamer.
In addition, none of the standard configurations use ACT_SIDE channels.
The rear channels of the 7.1 configuration have to be taken from
ACT_BACK. See the table in aacenc_lib.h, reproduced here:
----------------------------------------------------------------------------------------
ChannelMode | ChCfg | Height | front_El | side_El | back_El | lfe_El
-----------------------+-------+--------+---------------+----------+----------+---------
MODE_1 | 1 | NORM | SCE | | |
MODE_2 | 2 | NORM | CPE | | |
MODE_1_2 | 3 | NORM | SCE, CPE | | |
MODE_1_2_1 | 4 | NORM | SCE, CPE | | SCE |
MODE_1_2_2 | 5 | NORM | SCE, CPE | | CPE |
MODE_1_2_2_1 | 6 | NORM | SCE, CPE | | CPE | LFE
MODE_1_2_2_2_1 | 7 | NORM | SCE, CPE, CPE | | CPE | LFE
MODE_6_1 | 11 | NORM | SCE, CPE | | CPE, SCE | LFE
MODE_7_1_BACK | 12 | NORM | SCE, CPE | | CPE, CPE | LFE
-----------------------+-------+--------+---------------+----------+----------+---------
MODE_7_1_TOP_FRONT | 14 | NORM | SCE, CPE | | CPE | LFE
| | TOP | CPE | | |
-----------------------+-------+--------+---------------+----------+----------+---------
MODE_7_1_REAR_SURROUND | 0 | NORM | SCE, CPE | | CPE, CPE | LFE
MODE_7_1_FRONT_CENTER | 0 | NORM | SCE, CPE, CPE | | CPE | LFE
----------------------------------------------------------------------------------------
- NORM: Normal Height Layer. - TOP: Top Height Layer. - BTM: Bottom Height Layer.
- SCE: Single Channel Element. - CPE: Channel Pair. - LFE: Low Frequency Element.
Restores 8 channels to
https://www2.iis.fraunhofer.de/AAC/7.1auditionOutLeader_v2_rtb.mp4
projects / platform / upstream / gstreamer.git / commit