Do an audio mixdown before extracting audio

We have H.264, .mp4 wrapped files with multi track audio. It would be really nice to be able to use memo on these files directly
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]

Apparently Memo is using the first 2 track or the first pair of audio.

It could bew nice to have a checkbox in the settings to choose to perform a mixdown of all audio tracks for S2T.
More complex setup would be to allow the selection of the tracks to be used for S2T. (but this depends of trhe media)

An ideal workflow would be to be able to listen at individual audio track in Memo and select the track we would like to consider for S2T before triggering the process.

Describe alternatives you've considered
Doing a mixdown outside of memo

Additional context
Type of media uploaded:

`General
Complete name : /Volumes/storage3/60J-SHOOTING/TRANSLATE_EXPORT/230818_day37/C013C276_200315WV_CANON.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 33.3 MiB
Duration : 1 min 27 s
Overall bit rate : 3 175 kb/s
Frame rate : 25.000 FPS
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC
Writing application : Blackmagic Design DaVinci Resolve Studio

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L5.1
Format settings : CABAC / 2 Ref Frames
Format settings, CABAC : Yes
Format settings, Reference frames : 2 frames
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 1 min 27 s
Bit rate : 1 370 kb/s
Width : 3 840 pixels
Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 25.000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.007
Stream size : 14.4 MiB (43%)
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC
Color range : Limited
Color primaries : BT.709
Transfer characteristics : BT.709
Matrix coefficients : BT.709
Codec configuration box : avcC

Audio #1
ID : 2
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 27 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 1 channel
Channel layout : M
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.68 MiB (8%)
Default : Yes
Alternate group : 1
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC

Audio #2
ID : 3
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 27 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 1 channel
Channel layout : M
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.68 MiB (8%)
Default : Yes
Alternate group : 2
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC

Audio #3
ID : 4
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 27 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 1 channel
Channel layout : M
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.68 MiB (8%)
Default : Yes
Alternate group : 3
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC

Audio #4
ID : 5
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 27 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 1 channel
Channel layout : M
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.68 MiB (8%)
Default : Yes
Alternate group : 4
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC

Audio #5
ID : 6
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 27 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 1 channel
Channel layout : M
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.68 MiB (8%)
Default : Yes
Alternate group : 5
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC

Audio #6
ID : 7
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 27 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 1 channel
Channel layout : M
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.68 MiB (8%)
Default : Yes
Alternate group : 6
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC

Audio #7
ID : 8
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Duration : 1 min 27 s
Bit rate mode : Constant
Bit rate : 256 kb/s
Channel(s) : 1 channel
Channel layout : M
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
Stream size : 2.68 MiB (8%)
Default : Yes
Alternate group : 7
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC

Other
ID : 9
Type : Time code
Format : QuickTime TC
Duration : 1 min 27 s
Frame rate : 25.000 FPS
Time code of first frame : 11:49:54:00
Time code of last frame : 11:51:21:20
Time code, stripped : Yes
Language : English
Encoded date : 2024-06-04 07:57:32 UTC
Tagged date : 2024-06-04 07:57:32 UTC
`

No files, tests, or entry points are mentioned. Begin by locating the audio extraction and S2T workflow for multi-track MP4 input, then clarify whether the first milestone is an all-track mixdown or user-selected tracks. Done requires the agreed behavior to work on the reported seven-track sample.