Cavernize command-line arguments

All Cavern commands will be applied to the conversion expect for -fn, -f, and -format. If not defined, passes will be set automatically based on the recommendation for segment count, which is 2 pass if the source is only one segment, and 1 pass otherwise. If Cavern is not found near Cavernize, Cavernize Lite will be used (refer to the -cav argument).

First argument Path to the file. To convert all files in the folder which Cavernize is in, use "--folder".
-conv Export file name. If none given, it becomes Cavernized <source file name>.mkv, changing the output container to Matroska.
-astr Audio stream ID to convert. Starting from 0, only audio streams are counted. If not given, the audio track with the best quality will be selected.
-carg FFmpeg arguments when creating the final file. Default is empty, but if no value is given, and the output file name is .mkv, it becomes "-acodec libopus".
-hwaccel Use this to pass the -hwaccel argument to FFmpeg.
-seg Segment length in seconds. Longer inputs can be converted by segmenting them to avoid memory limits. This behaviour is required as Cavern does not have its own audio file importer in the driver yet, and Unity loads the entire input audio file to the system memory. Cavernize Lite can convert as it reads the input file, so this argument is skipped for conversions with that version. Default is 600.
-vstr Video stream ID to keep. Starting from 0, only video streams are counted. -1, if only audio is converted. Default is 0.
-cav If Cavern is not found near Cavernize (or this argument is given), Cavernize Lite will be used. It is a lightweight version of Cavern's converter, without the -passes argument, but it's hundreds of times faster (literally). Cavernize Lite supports regular conversion, and 5 layouts for systems without a Cavern installation:
- 0: disable Cavernize, conversion only
- 1 (default): try to use the Cavern configuration of the current system, or 5.1.2 if it's not available
- 301: 3.0.1 - front left, front right, rear center, top
- 312: 3.1.2 - front left, front right, rear center, LFE, top side left, top side right
- 402: 4.0.2 - front left, front right, rear left, rear right, top side left, top side right
- 404: 4.0.4 - front left, front right, rear left, rear right, top front left, top front right, top rear left, top rear right
- 512: 5.1.2 - front left, front right, center, LFE, side left, side right, top side left, top side right

Audio format info

Consider checking this table before overriding Cavern's recommended MKV/Opus output. Good LFE quality means it's completely or mostly retained, medium quality means it keeps some low frequency data, and bad quality means the data is completely destroyed. If you use channel 4 for anything other than LFE, only use a codec with good LFE quality, otherwise it becomes unusable.

Codec FFmpeg ID Container Max channels[1] LFE quality Audio quality
PCM integer s16le, s16be, s24le, s24be, s32le, s32be MKV 65536 (64) Raw Raw
FLAC flac MKV, OGG 8 Lossless Lossless
Opus libopus MKV, WebM, OGG 255 (64[2]) Good Good
Vorbis libvorbis MKV, RMVB, WebM, OGG 255 (64) Good Good
DTS Coherent Acoustics dca with -strict -2 MKV, BD (M2TS) 8 Good Good
Dolby Digital Plus eac3 MKV, BD (M2TS) 8 (6) Medium Good
Dolby Digital ac3 MKV, MP4, TV (PS/TS), DVD (VOB), BD (M2TS) 6 Medium Good
AAC aac MKV, MP4, FLV, 3GP, TV (PS/TS), RMVB 6 Bad Medium
MP3 libmp3lame MKV, MP4, FLV, MPG, TV (PS/TS) 2 Not available Medium
MP2 libtwolame MKV, MP4, MPG, TV (PS/TS), DVD (VOB) 2 Not available Medium
MP2 mp2 MKV, MP4, MPG, TV (PS/TS), DVD (VOB) 2 Not available Bad

[1] - FFmpeg's limits are in brackets when they differ from the format's maximum.
[2] - With the "-mapping_family 255" argument.

Batch samples

Cavernize movie for systems with badly routed bass

If your amplifier/receiver outputs not just the LFE channel, but the fronts too to the subwoofer, use the following command to somewhat compensate for it:
"Cavernize for FFmpeg.exe" %1 -lfe off -lfev 80
This will make the transitions of sources moving from/to the fronts less noticeable.

Cavernize this folder and subfolders

Run this batch code to go through all your MP4 files, and Cavernize them:
for /r %%i in (./*.mp4) do "Cavernize for FFmpeg.exe" "%%i"