Apple TV 4K cannot handle ALAC with 8 channels
Hello,
Movie has ALAC audio stream (8 channels):
© WARNER BROS.
But is playing back with 6 channels:
De facto Apple TV 4K does this downmix:
ALAC 7.1 --> PCM 5.1: FL:FL FR:FR CTR:CTR SUB:SUB SL:SL SR:SR RL:FL+CTR RR:FR+CTR
Same movie now has AAC audio stream (8 channels):
© WARNER BROS.
Is playing back with 8 channels:
Same procedure with iTunes:
Movie has ALAC audio stream (8 channels) and is playing back with 8 channels:
Same movie now has AAC audio stream (8 channels) and is also playing back with 8 channels:
Apple TV audio settings:
ALAC audio stream:
Audio #2
ID : 3
Format : ALAC
Codec ID : alac
Codec ID/Info : Apple Lossless Audio Codec
Duration : 2 h 56 min
Duration_LastFrame : -83 ms
Bit rate mode : Variable
Bit rate : 4 671 kb/s
Nominal bit rate : 9 216 kb/s
Channel(s) : 8 channels
Sampling rate : 48.0 kHz
Bit depth : 24 bits
Stream size : 5.75 GiB (16%)
Language : German
Default : Yes
Alternate group : 1
Subtitles : 5
AAC audio stream:
Audio #2
ID : 3
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 2 h 56 min
Source duration : 2 h 56 min
Source_Duration_LastFrame : -19 ms
Bit rate mode : Variable
Bit rate : 729 kb/s
Maximum bit rate : 1 102 kb/s
Channel(s) : 8 channels
Channel layout : C L R Ls Rs Lb Rb LFE
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 918 MiB (3%)
Source stream size : 918 MiB (3%)
Language : German
Default : Yes
Alternate group : 1
Menus : 4
mdhd_Duration : 10571267
Sample files to reproduce:
Hardware used:
- Apple TV 4K (2021)
Software used:
- tvOS v18.0
- iTunes v12.13.4.4
Apple TV 4K, tvOS 18
