AAC 7.1 channels mixed up in decoding
|Reported by:||kmamal||Owned by:|
|Blocking:||Reproduced by developer:||no|
|Analyzed by developer:||no|
Summary of the bug:
I have an 8 channel audio file that I'm encoding as AAC. When inspecting the channels of the created aac file using ffmpeg, they appear to be in the wrong order or even added together.
This appears to be a problem in decoding, as inspecting the aac file with other software (I used Audacity) shows the channels in the correct order.
This problem appeared in ffmpeg 4.3. In ffmpeg 4.2.4 the channels are ok.
How to reproduce:
I'm using the 8_Channel_ID.wav file attached to this ticket.
I'm encoding to AAC using:
ffmpeg -i 8_Channel_ID.wav out.aac
First I inspect the channels using:
ffmpeg -i out.aac -filter_complex "showwavespic=s=1280x480:split_channels=1" -frames:v 1 -f image2 - | display
The result looks like the first two channels have been swapped with the last two.
Then I inspect the channels using:
ffmpeg -i out.aac -filter_complex "channelsplit=channel_layout=7.1,join=inputs=8:channel_layout=7.1,showwavespic=s=1280x480:split_channels=1" -frames:v 1 -f image2 - | display
The result looks like the last two channels have been added to the first two.