Can't get my mkvmerge script to work

[ElegantRain]

Hello, I have 7 seasons of a rare old TV show that can't be found anywhere else. I want to avoid a generation loss by converting the file. The uploader probably thought that it would be a good idea to do 700 episodes in 16x9 even though it was originally shot in 4x3. I wrote this script with the help of chat GPT and no matter what I do batch is complaining about a track#4, which I don't understand where that comes from. My script and the video files don't even have any mention of track #4.

Error

A track with the ID 4 was requested but not found in the file. The corresponding option will be ignored.

Here's my script

@echo off
if [%1]==[] goto:eof

set "sourceFolder=%~dp1"
set "outputFolder=%sourceFolder%\remuxed"

if not exist "%outputFolder%" (
  mkdir "%outputFolder%"
)

:loop

"C:\Program Files\MKVToolNix\mkvmerge.exe" -o "%outputFolder%\%~nx1" --aspect-ratio 4:3 --track-order 0:0,0:0 "%~1"

shift

if not [%1]==[] goto:loop

:eof
pause
exit

I tried many things like --video-tracks all but it doesn't work. I'm at loss and would like to preserve those file.

Thanks to anyone who can help with this!

[ElegantRain]

I'm dumb, it's always when you post it that you see you had it in big caps in your face that whole time.

0:4/3

Fixed it all!

[Luke M]

fyi, this changes the container aspect ratio but the video stream aspect ratio might be wrong (which one is used depends on the player). Check it with ffmpeg -i or Mediainfo.

[ElegantRain]

fyi, this changes the container aspect ratio but the video stream aspect ratio might be wrong (which one is used depends on the player). Check it with ffmpeg -i or Mediainfo.

Here's the remuxed MediaInfo of the file.

General
Format                                   : Matroska
Format version                           : Version 4
File size                                : 244 MiB
Duration                                 : 24 min 38 s
Overall bit rate                         : 1 387 kb/s
Encoded date                             : UTC 2023-05-27 01:19:18
Writing application                      : mkvmerge v71.1.0 ('Fortitude') 64-bit
Writing library                          : libebml v1.4.4 + libmatroska v1.7.1

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings                          : CABAC / 16 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 16 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 24 min 38 s
Bit rate                                 : 1 001 kb/s
Width                                    : 624 pixels
Height                                   : 352 pixels
Display aspect ratio                     : 4:3
Original display aspect ratio            : 16:9
Frame rate mode                          : Constant
Frame rate                               : 29.970 (30000/1001) FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.152
Stream size                              : 176 MiB (72%)
Writing library                          : x264 core 148 r2638 7599210
Encoding settings                        : cabac=1 / ref=16 / deblock=1:0:0 / analyse=0x3:0x133 / me=umh / subme=10 / psy=1 / psy_rd=1.00:0.00 / 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=8 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=300 / keyint_min=29 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=18.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=62500 / vbv_bufsize=78125 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
Default                                  : Yes
Forced                                   : No

It is showing the following

Display aspect ratio : 4:3
Original display aspect ratio : 16:9

The flag is being picked up correctly in VLC but Plex is ignoring it. Do you know any better way that would be compatible with Plex without engendering a generation loss and convert?

[jagabo]

ffmpeg can set the h.264 sar flags with a remux. See sample_aspect_ratio:

https://ffmpeg.org/ffmpeg-bitstream-filters.html#h264_005fmetadata

ffmpeg -i input.mp4 -c copy -bsf:v "h264_metadata=sample_aspect_ratio=3/4" output.mp4

[ElegantRain]

ffmpeg can set the h.264 sar flags with a remux. See sample_aspect_ratio:

https://ffmpeg.org/ffmpeg-bitstream-filters.html#h264_005fmetadata

ffmpeg -i input.mp4 -c copy -bsf:v "h264_metadata=sample_aspect_ratio=3/4" output.mp4

To be honest I think I deleted the original files since there was 700 episodes and it was eating up hard drive space.

Would setting this flag work with the "Display aspect ratio : 4:3" flag?

Thanks for helping!

[jagabo]

ffmpeg can set the h.264 sar flags with a remux. See sample_aspect_ratio:

https://ffmpeg.org/ffmpeg-bitstream-filters.html#h264_005fmetadata

ffmpeg -i input.mp4 -c copy -bsf:v "h264_metadata=sample_aspect_ratio=3/4" output.mp4

To be honest I think I deleted the original files since there was 700 episodes and it was eating up hard drive space.

Would setting this flag work with the "Display aspect ratio : 4:3" flag?

Thanks for helping!

You would probably want to do both. Some players will obey the codec's flag, some the container's flag, and some will ignore both of them.

Note that the sar flag I used in the example assumes the source is square pixel (SAR 1:1) with a 16:9 frame size. So the pixels need to squeezed horizontally to force a 4:3 display size.