The following command works, but results in the rear channels getting mapped to the front L & R speakers:
afconvert -v -f 'm4af' -d 'aac ' -c 8 -l MPEG_7_1_A -l AAC_7_1 -b 768000 -q 127 -s 2 in.caf out.mp4 ( aside: ffprobe of out.mp4 results in: [aac @ 0x7f7fb4013a00] Assuming an incorrectly encoded 7.1 channel layout instead of a spec-compliant 7.1(wide) layout, use -strict 1 to decode according to the specification instead. ) ( aside: ffplay -strict 1 out.mp4 plays correctly ) I think I need to be using a different channel layout in the afconvert call: -l AAC_7_1_B This is defined: - https://developer.apple.com/documentation/coreaudiotypes/kaudiochannellayouttag_aac_7_1_b I’m on Mojave, but: afconvert -v -f 'm4af' -d 'aac ' -c 8 -l MPEG_7_1_A -l AAC_7_1_B -b 768000 -q 127 -s 2 in.caf out.mp4 Throws an error: Error: ExtAudioFileSetProperty ('cfmt') failed ('!dat’) Any help would be appreciated. Thanks. Mark
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