libobs/media-io: Change speaker layout to match FFmpeg aac. #1182
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(also changes obs-ffmpeg).
The default channel layouts from aac spec are implemented in FFmpeg native
aac encoder as:
AV_CH_LAYOUT_MONO,
AV_CH_LAYOUT_STEREO,
AV_CH_LAYOUT_SURROUND,
AV_CH_LAYOUT_4POINT0,
AV_CH_LAYOUT_5POINT0_BACK,
AV_CH_LAYOUT_5POINT1_bACK,
AV_CH_LAYOUT_7POINT1,
The correspondence of speaker layouts to AV_CH_LAYOUT from FFmpeg is
changed to reflect the previous table.
Although FFmpeg native aac encoder can now encode all the layouts listed
in avutil channel_layout.h (on master), there might be issues with older FFmpeg
binaries.
Note that 2.1 speaker layout will be encoded as AV_CH_LAYOUT_SURROUND
(FL FR FC) because it is not listed as the default layout for three
channels.
This just means some optimizations for LFE channel will not be used by
the encoder which will treat it as an SCE (single channel element).
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Related bug report: #1163 I think 3 channels setup not required at all. The controversial info placed in the code intentionally may cause future problems in the development. Also, it should change the 48a8e75 for OBS SPEAKERS_2POINT1 description and MS KSAUDIO_SPEAKER_2POINT1 (custom made) value for audio monitoring. The forum has number of logs that shows only 2 channels usage. It is wise to wait to gather more info on multi-channel formats usage requested by end-users. |
That's your opinion. Please could you not conflate your own usage to other people's case-uses ?
No need to change anything as I explained in detail. This will be properly encoded as 2.1 by FFmpeg native aac if ffmpeg is on git head (or later than commit fc9dcfe7d50d7 dated nov 9 2017); on earlier FFmpeg with this commit it will be encoded as 3.0 which just means some low-pass filter is not applied by the encoder.
This requires a separate commit . You can resubmit that if you want. But that would be purely cosmetic with no impact.
The release is what ? 11 days old ... |
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You had a bit of a submodule issue there, I fixed it and will merge shortly. |
(This commit also modifies the obs-ffmpeg module)
The default channel layouts from aac spec are implemented in FFmpeg
native aac encoder as follows:
AV_CH_LAYOUT_MONO,
AV_CH_LAYOUT_STEREO,
AV_CH_LAYOUT_SURROUND,
AV_CH_LAYOUT_4POINT0,
AV_CH_LAYOUT_5POINT0_BACK,
AV_CH_LAYOUT_5POINT1_BACK,
AV_CH_LAYOUT_7POINT1,
The correspondence of speaker layouts to AV_CH_LAYOUT from FFmpeg is
changed to reflect the previous table.
Although FFmpeg native aac encoder can now encode all the layouts listed
in avutil channel_layout.h (on master), there might be issues with older
FFmpeg binaries.
Note that 2.1 speaker layout will be encoded as AV_CH_LAYOUT_SURROUND
(FL FR FC) because it is not listed as the default layout for three
channels.
This just means some optimizations for LFE channel will not be used by
the encoder which will treat it as an SCE (single channel element).
Closes obsproject#1182
(also changes obs-ffmpeg).
The default channel layouts from aac spec are implemented in FFmpeg native
aac encoder as:
AV_CH_LAYOUT_MONO,
AV_CH_LAYOUT_STEREO,
AV_CH_LAYOUT_SURROUND,
AV_CH_LAYOUT_4POINT0,
AV_CH_LAYOUT_5POINT0_BACK,
AV_CH_LAYOUT_5POINT1_bACK,
AV_CH_LAYOUT_7POINT1,
The correspondence of speaker layouts to AV_CH_LAYOUT from FFmpeg is
changed to reflect the previous table.
Although FFmpeg native aac encoder can now encode all the layouts listed
in avutil channel_layout.h (on master), there might be issues with older FFmpeg
binaries. This PR fixes those issues for 2.1 and 5.1 layouts.
NB:
Note that 2.1 speaker layout will be encoded as AV_CH_LAYOUT_SURROUND
(FL FR FC) because it is not listed as the default layout for three
channels.
This just means some optimizations for LFE channel will not be used by
the encoder which will treat it as an SCE (single channel element).