Apple TV 4K missing bass

Hi all,

recently I bought a mediaplayer with Kodi. Now I see, that MKV files with 5.1 surround sound plays the LFE/bass very quietly on Infuse compared to this Kodi Player.

The same movie (Transformers 4) plays on Netflix via Apple TV 4K on the same bass loudness like on the Kodi Player. So Infuse (and also MrMC) have a problem with bass. I think it has something to do with missing Dolby flags/tags for LFE +10dB.

I am using an Yamaha RXV685 directly connected via HDMI to the ATV4K. AVR is getting PCM like it should when selected best quality sound in tvOS settings.

Would you be able to send in a sample video you are seeing issues with?

Transformers is just an example. I tested several movies and it seems to be the same behaviour everytime.

mediainfo for Transformers:

Format : Matroska
Format version : Version 2
File size : 19.7 GiB
Duration : 2 h 45 min
Overall bit rate : 17.1 Mb/s
Movie name : PS!!!
Encoded date : UTC 2014-11-18 01:41:31
Writing application : mkvmerge v3.4.0 (‘Rapunzel’) gebaut am May 15 2010 09:38:20
Writing library : libebml v0.8.0 + libmatroska v0.9.0

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings : CABAC / 4 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 4 frames
Codec ID : V_MPEG4/ISO/AVC
Duration : 2 h 45 min
Bit rate : 15.4 Mb/s
Width : 1 920 pixels
Height : 1 020 pixels
Display aspect ratio : 1.882
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.329
Stream size : 17.8 GiB (91%)
Title : 1080p IMAX
Writing library : x264 core 125 r2200 999b753
Encoding settings : cabac=1 / ref=4 / deblock=1:-2:-2 / analyse=0x3:0x113 / me=umh / subme=9 / psy=1 / psy_rd=1.10:0.00 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=0 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=5 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=23 / scenecut=40 / intra_refresh=0 / rc=crf / mbtree=0 / crf=20.5 / qcomp=0.60 / qpmin=16 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / pb_ratio=1.30 / aq=1:1.00
Language : English
Default : Yes
Forced : Yes

Audio #1
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : A_AC3
Duration : 2 h 45 min
Bit rate mode : Constant
Bit rate : 640 kb/s
Channel(s) : 6 channels
Channel layout : L R C LFE Ls Rs
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Compression mode : Lossy
Stream size : 756 MiB (4%)
Title : German RETAIL
Language : German
Service kind : Complete Main
Default : Yes
Forced : Yes

Audio #2
ID : 3
Format : AC-3
Format/Info : Audio Coding 3
Commercial name : Dolby Digital
Codec ID : A_AC3
Duration : 2 h 45 min
Bit rate mode : Constant
Bit rate : 640 kb/s
Channel(s) : 6 channels
Channel layout : L R C LFE Ls Rs
Sampling rate : 48.0 kHz
Frame rate : 31.250 FPS (1536 SPF)
Compression mode : Lossy
Stream size : 756 MiB (4%)
Language : English
Service kind : Complete Main
Default : No
Forced : No

Text #1
ID : 4
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Title : German FORCED
Language : German
Default : Yes
Forced : Yes

Text #2
ID : 5
Format : VobSub
Muxing mode : zlib
Codec ID : S_VOBSUB
Codec ID/Info : Picture based subtitle format used on DVDs
Language : German
Default : No
Forced : No

Text #3
ID : 6
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Title : English FORCED
Language : English
Default : No
Forced : Yes

Text #4
ID : 7
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Title : English
Language : English
Default : No
Forced : No

Menu
00:00:00.000 : en:00:00:00.000
00:06:51.578 : en:00:06:51.578
00:14:33.581 : en:00:14:33.581
00:21:37.463 : en:00:21:37.463
00:30:13.395 : en:00:30:13.395
00:38:45.990 : en:00:38:45.990
00:46:08.057 : en:00:46:08.057
00:51:39.513 : en:00:51:39.513
00:59:09.337 : en:00:59:09.337
01:07:48.648 : en:01:07:48.648
01:15:14.552 : en:01:15:14.552
01:23:25.292 : en:01:23:25.292
01:29:14.724 : en:01:29:14.724
01:37:16.956 : en:01:37:16.956
01:44:35.436 : en:01:44:35.436
01:51:25.053 : en:01:51:25.053
01:57:47.936 : en:01:57:47.936
02:04:48.481 : en:02:04:48.481
02:12:35.865 : en:02:12:35.865
02:21:04.206 : en:02:21:04.206
02:28:48.670 : en:02:28:48.670
02:37:09.629 : en:02:37:09.629

I haven’t heard of a bass boost tag on a file. Is it perhaps the reverse where infuse is correct and others are doubling bass through a setting? Possibly an issue with room correction or maybe specific to pcm receiver settings such that bass isn’t loud enough?

No the bass sounds like it should on the other devices/apps. Infuse is definitely to low in bass. Same settings everywhere, my system isn’t new either.

This whole “Apple TV 4K magically converts everything to PCM” pisses me off. Fact is, you never know, what they actually do in this process. When they dropped bitstream support, they made the biggest mistake in my opinion.

I’m pretty sure Firecore knows such problems, but they can’t fight against it due to tvOS limitations. Same thing with real 24p playback. But this is another sad story.