I have tested the feature to embed more than one audio stream into a download.
For the initial test I downloaded a video with an English audio track and an autogenerated audio track (German).
I am unaware of creators that use their own audio tracks, beside Mr. Beast, so I tested with one of his videos. (https://www.youtube.com/watch?v=gVE2t-LRK-s).
Both include the audio tracks I selected.
I noticed that the language property of the audio tracks is either not set, or set to English. I tested this with MKV (preferred container) and with MP4, selected it to be forced to see if it makes a difference. Different audio formats (Opus and mp4a) show the same results.
MP4 example:
Whatever You Hide As, You Keep!1920x1080[gVE2t-LRK-s].mp4
General
Complete name : Whatever You Hide As, You Keep!1920x1080[gVE2t-LRK-s].mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/av01/iso2/mp41)
File size : 495 MiB
Duration : 24 min 19 s
Overall bit rate mode : Variable
Overall bit rate : 2 846 kb/s
Frame rate : 59.940 FPS
Writing application : Lavf63.1.101
Video
ID : 1
Format : AV1
Format/Info : AOMedia Video 1
Format profile : Main@L4.1
Codec ID : av01
Duration : 24 min 19 s
Bit rate : 2 436 kb/s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 59.940 (60000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Bits/(Pixel*Frame) : 0.020
Stream size : 424 MiB (86%)
Title : ISO Media file produced by Google Inc.
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : av1C
Audio 1
ID : 2
Format : Opus
Codec ID : Opus
Duration : 24 min 19 s
Source duration : 24 min 19 s
Source_Duration_FirstFrame : 1 ms
Bit rate mode : Variable
Bit rate : 133 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Compression mode : Lossy
Stream size : 23.1 MiB (5%)
Source stream size : 23.1 MiB (5%)
Language : English
Default : Yes
Alternate group : 1
Audio 2
ID : 3
Format : Opus
Codec ID : Opus
Duration : 24 min 19 s
Source duration : 24 min 19 s
Source_Duration_FirstFrame : 1 ms
Bit rate mode : Variable
Bit rate : 132 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Compression mode : Lossy
Stream size : 22.9 MiB (5%)
Source stream size : 22.9 MiB (5%)
Language : English
Default : Yes
Alternate group : 2
Audio 3
ID : 4
Format : Opus
Codec ID : Opus
Duration : 24 min 19 s
Source duration : 24 min 19 s
Source_Duration_FirstFrame : 1 ms
Bit rate mode : Variable
Bit rate : 131 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Compression mode : Lossy
Stream size : 22.8 MiB (5%)
Source stream size : 22.8 MiB (5%)
Language : English
Default : Yes
Alternate group : 3
MKV example:
Whatever You Hide As, You Keep!1920x1080[gVE2t-LRK-s].mkv
General
Unique ID : 10463616780851794033539488559232566568 (0x7DF38234A41206434B777BAA095C528)
Complete name : Whatever You Hide As, You Keep!1920x1080[gVE2t-LRK-s].mkv
Format : Matroska
Format version : Version 4
File size : 492 MiB
Duration : 24 min 19 s
Overall bit rate : 2 830 kb/s
Frame rate : 59.940 FPS
Writing application : Lavf63.1.101
Writing library : Lavf63.1.101
ErrorDetectionType : Per level 1
Video
ID : 1
Format : AV1
Format/Info : AOMedia Video 1
Format profile : Main@L4.1
Codec ID : V_AV1
Duration : 24 min 19 s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 59.940 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Title : ISO Media file produced by Google Inc.
Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Audio 1
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : A_AAC-2
Duration : 24 min 19 s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Title : ISO Media file produced by Google Inc.
Language : English
Default : Yes
Forced : No
Audio 2
ID : 3
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : A_AAC-2
Duration : 24 min 19 s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Title : ISO Media file produced by Google Inc.
Default : Yes
Forced : No
Audio 3
ID : 4
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : A_AAC-2
Duration : 24 min 19 s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 43.066 FPS (1024 SPF)
Compression mode : Lossy
Title : ISO Media file produced by Google Inc.
Default : Yes
Forced : No
MKV example with opus (only two tracks):
Whatever You Hide As, You Keep!1920x1080[gVE2t-LRK-s opus].mkv
General
Unique ID : 279338924355836809074901098945810698570 (0xD226B84BB164F40E1C02A28CF30E914A)
Complete name : Whatever You Hide As, You Keep!1920x1080[gVE2t-LRK-s opus].mkv
Format : Matroska
Format version : Version 4
File size : 471 MiB
Duration : 24 min 19 s
Overall bit rate : 2 708 kb/s
Frame rate : 59.940 FPS
Writing application : Lavf63.1.101
Writing library : Lavf63.1.101
ErrorDetectionType : Per level 1
Video
ID : 1
Format : AV1
Format/Info : AOMedia Video 1
Format profile : Main@L4.1
Codec ID : V_AV1
Duration : 24 min 19 s
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 59.940 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Title : ISO Media file produced by Google Inc.
Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Audio 1
ID : 2
Format : Opus
Codec ID : A_OPUS
Duration : 24 min 19 s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Bit depth : 32 bits
Compression mode : Lossy
Language : English
Default : Yes
Forced : No
Audio 2
ID : 3
Format : Opus
Codec ID : A_OPUS
Duration : 24 min 19 s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Bit depth : 32 bits
Compression mode : Lossy
Language : English
Default : Yes
Forced : No
I don't consider this to be a bug, but now the question is whenever you have any control over the langages that are set as property within the file. The language is detected and shown in YTSage 5.5.0, but the properties the container gets don't match that. If that can be passed alongby YTSage, this is a feature request, as long as that is not cumbersome to do.
Manually editing the file is an option for me.
Edit: Removed the hashtag, since GitHub was treating them as reference.
I have tested the feature to embed more than one audio stream into a download.
For the initial test I downloaded a video with an English audio track and an autogenerated audio track (German).
I am unaware of creators that use their own audio tracks, beside Mr. Beast, so I tested with one of his videos. (https://www.youtube.com/watch?v=gVE2t-LRK-s).
Both include the audio tracks I selected.
I noticed that the language property of the audio tracks is either not set, or set to English. I tested this with MKV (preferred container) and with MP4, selected it to be forced to see if it makes a difference. Different audio formats (Opus and mp4a) show the same results.
MP4 example:
MKV example:
MKV example with opus (only two tracks):
I don't consider this to be a bug, but now the question is whenever you have any control over the langages that are set as property within the file. The language is detected and shown in YTSage 5.5.0, but the properties the container gets don't match that. If that can be passed alongby YTSage, this is a feature request, as long as that is not cumbersome to do.
Manually editing the file is an option for me.
Edit: Removed the hashtag, since GitHub was treating them as reference.