I have multiple audio tracks and subtitles to extract in a single .mkv file. I'm new to ffmpeg commands, this is what I've tried (audio):

ffmpeg -i VIDEO.mkv -vn -acodec copy AUDIO.aac

It just extract 1 audio. What I want is tell ffmpeg to extract every single audio files and subtitle files to a destination, and keep the original name of each files and extensions. (Because I don't know which extension does the audio files are, sometimes maybe .flac or .aac).

I'm not sure about the solutions I'd found online, because it's quite complicated, and I need explanations to know how it's works, so that I can manipulate the command in the future. By the way, I planned to run the code from Windows CMD.

Thanks.

There is no option yet in ffmpeg to automatically extract all streams into an appropriate container, but it is certainly possible to do manually.

You only need to know the appropriate containers for the formats you want to extract.

Default stream selection only chooses one stream per stream type, so you have to manually map each stream with the -map option.

1. Get input info

Using ffmpeg or ffprobe you can get the info in each individual stream, and there is a wide variety of formats (xml, json, cvs, etc) available to fit your needs.

ffmpeg example

ffmpeg -i input.mkv

The resulting output (I cut out some extra stuff, the stream numbers and format info are what is important):

Input #0, matroska,webm, from 'input.mkv':
  Metadata:
  Duration: 00:00:05.00, start: 0.000000, bitrate: 106 kb/s
    Stream #0:0: Video: h264 (High 4:4:4 Predictive), yuv444p, 320x240 [SAR 1:1 DAR 4:3], 25 fps, 25 tbr, 1k tbn, 50 tbc (default)
    Stream #0:1: Audio: vorbis, 44100 Hz, mono, fltp (default)
    Stream #0:2: Audio: aac, 44100 Hz, mono, fltp (default)
    Stream #0:3: Audio: flac, 44100 Hz, mono, fltp (default)
    Stream #0:4: Subtitle: ass (default)

ffprobe example

ffprobe -v error -show_entries stream=index,codec_name,codec_type input.mkv

The resulting output:

[STREAM]
index=0
codec_name=h264
codec_type=video
[/STREAM]
[STREAM]
index=1
codec_name=vorbis
codec_type=audio
[/STREAM]
[STREAM]
index=2
codec_name=aac
codec_type=audio
[/STREAM]
[STREAM]
index=3
codec_name=flac
codec_type=audio
[/STREAM]
[STREAM]
index=4
codec_name=ass
codec_type=subtitle
[/STREAM]

2. Extract the streams

Using the info from one of the commands above:

ffmpeg -i input.mkv \
-map 0:v -c copy video_h264.mkv \
-map 0:a:0 -c copy audio0_vorbis.oga \
-map 0:a:1 -c copy audio1_aac.m4a \
-map 0:a:2 -c copy audio2.flac \
-map 0:s -c copy subtitles.ass

In this case, the example above is the same as:

ffmpeg -i input.mkv \
-map 0:0 -c copy video_h264.mkv \
-map 0:1 -c copy audio0_vorbis.oga \
-map 0:2 -c copy audio1_aac.m4a \
-map 0:3 -c copy audio2.flac \
-map 0:4 -c copy subtitles.ass

• I prefer the first example because the input file index:stream specifier:stream index is more flexible and efficient; it is also less prone to incorrect mapping.

• See documentation on stream specifiers and the -map option to fully understand the syntax. Additional info is in the answer to FFmpeg mux video and audio (from another video) - mapping issue.

• These examples will stream copy (re-mux) so no re-encoding will occur.

Container formats

A partial list to match the stream with the output extension for some common formats: