In VLC, "keep the original track" means exactly one thing: no transcoding at all. The stream that came in is the stream written out; only the container around it changes. That decides whether your conversion is a copy operation or a re-encode — and VideoLAN documents the boundary in its own words.
VideoLAN's own definition
The sentence lives on VideoLAN's wiki, on the Transcode page:
"If your input streams already matches the encoding that you desire for your output stream, then you don't have to transcode at all (just leave out the transcode settings on the command line, and it will thence not transcode). In the GUI this is called "keep the original track" (I think)."
The "(I think)" is in the original. The mechanism is stated flatly: leave the transcode settings out and nothing gets transcoded. Only the GUI's name for it is hedged, and the hedge is still there. Presenting this as a firm official statement about the interface quotes more confidence than the source contains.
And that page carries a banner of its own: "This page is outdated and information might be incorrect." VideoLAN's documentation index says the same across the board — "Parts of this documentation are currently outdated or incomplete."
The reward is stated on a different page. VideoLAN's support guide — which describes itself as informal — says of extracting audio: "If you want the extracted audio in the same format as it is stored in the input, then VLC can provide it to you with no loss of quality, because there is no re-encoding of the content."
Remux and transcode, as VLC draws the line
VideoLAN defines transcoding as "the process of taking a video file and changing it to a different format or bitrate," and the two ingredients separately: a codec is "a compression algorithm, used to reduce the size of a stream"; a container "contains one or several streams already encoded by codecs." So:
- Remux — the container changes, the encoded streams are carried across untouched. This is what "keep the original track" produces.
- Transcode — the streams change format or bitrate, which means re-encoding, which means a new generation of the content.
VideoLAN attaches warnings to transcoding that it does not attach to the other path: you need "enough space on your hard drive to store this extra file," and "a reasonably fast computer, as transcoding can be very slow."
One architectural note explains VLC's odd interface: "In VLC, transcoding is exactly the same as streaming across a network, except that the output is sent to a file instead of a network." Hence the dialog that looks like a streaming setup, and the --sout- prefix on every relevant option.
The one condition you have to satisfy
The condition is in that quote: your input must "already matches the encoding that you desire for your output stream." The less obvious half is that the container also has to accept the codec, and VideoLAN is explicit about what happens when it does not:
"If your current format is incompatible with the muxer you desire, then you must transcode it to something compatible, or choose a different muxer. If you choose an incompatible stream for a given muxer, it may silently fail. You can look for error messages in the messages window to help you debug the failures."
"It may silently fail" is the sentence to remember. VLC will not necessarily stop you or show an error dialog; it may simply hand you a file with a track missing. The page on merging files states the rule positively: "no transcoding is necessary if all streams match."
One caveat: the compatibility matrix that quote points to is gone — the page now returns "There is currently no text in this page." What survives is VideoLAN's per-muxer documentation for the mux option:
mux | Video codecs listed | Audio codecs listed |
|---|---|---|
ts | MPEG 1/2/4, MJPEG, H263, H264, I263, WMV 1/2, Theora | MPEG audio, AAC, a52 |
ps | MPEG 1/2, MJPEG | MPEG audio, a52 |
mpeg1 | MPEG 1 | MPEG audio |
ogg | MPEG 1/2/4, MJPEG, WMV 1/2, Theora | vorbis, flac, speex, a52, MPEG audio |
asf | MPEG-4, MJPEG, WMV 1/2 | MPEG audio, a52 |
avi | MPEG 1/2/4, H263, H264, I263 | MPEG audio, a52 |
mpjpeg | MJPEG only | none — "No sound track can be muxed in such streams" |
Three things to take from it. The audio whitelists are narrow — the structural reason a conversion comes back silent. The avi row comes with a warning VideoLAN wrote about its own code: "The avi muxer in VLC is known to produce corrupt files." And MP4, MKV and WebM are not in this list at all — a gap in the documentation, not a statement that VLC cannot write them, since the same wiki uses mux="mp4" in its own examples. VideoLAN explains why no static table exists: "Since supported codecs are dynamically assigned by the running program, sout-transcode-venc, sout-transcode-aenc and sout-transcode-senc have been left blank." Run vlc -H to see what your build offers.
Using it in the interface
The entry point is documented: "Open the Media menu and select Convert/Save." VideoLAN describes the wizard in one line — "You will then be asked what format to convert to: you can give a video codec, an audio codec and a container format."
That is all the official documentation says about the dialog. It names no built-in profile and does not describe where the "keep the original track" control sits. Walkthroughs built around named presets are describing a build, not a documented interface.
If your codec is not one the target container accepts, keeping the original track is off the table and re-encoding is the only way through — which need not mean installing anything:
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
That runs inside your browser tab: the file is read from disk, re-encoded locally, and handed straight back, with no upload and no server copy. If you only need a different wrapper, there are single-purpose browser converters for the common pairs, including MP4 to MKV and MOV to MP4; the full set is on the tools page.
The command-line equivalent
On the command line, keeping the original track is an absence rather than a setting, and the granularity is per-stream: "The transcode statement can contain vcodec and vb to change the video codec and acodec and ab to change the audio codec. If vcodec is missing, the video codec will stay the same (same for acodec)."
So specifying acodec while omitting vcodec re-encodes the audio and carries the video across untouched; dropping the #transcode{} block entirely re-encodes nothing. VideoLAN's own lossless example does exactly that, pulling AC3 audio off a DVD on Linux:
vlc --no-sout-video dvdsimple:///dev/scd0@1:1 :sout='#std{access=file,mux=raw,dst=./file.ac3}'Two documented details there are easy to miss. "The access=file instructs vlc to store the output in a file (and not stream it), and the dst is the destination of the new (output) file." And the leading colon matters: ":sout means that the option sout applies only to the preceding stream, not to the whole command line."
Two more official notes. If a conversion refuses to complete, check your playback settings — "without the options --no-repeat --no-loop, you may find that loop options selected in the GUI cause transcodes to fail." And test on a fragment first: "it's advisable to use an option like --stop-time=30 to only encode the first 30 seconds—this means you can check the file has transcoded correctly, and that the output is of a suitable quality." That note is written for the command line; VideoLAN adds that on macOS the trick does not seem to work, and suggests pressing Ctrl-C instead, after which "VLC will properly write out the already transcoded segment".
How to tell it worked
Play the output and check every track, not just the picture. Because an incompatible codec "may silently fail," a missing audio stream is the expected failure mode and nothing will announce it. If a track is gone, the documented next step is the messages window, where errors that never reached a dialog are logged.
FAQ
Is "keep the original track" the same as remuxing? Functionally yes, as VideoLAN describes it: the container changes and the encoded streams do not. If your input already matches the encoding you want, "you don't have to transcode at all" — with the "(I think)" attached to the GUI's name for it, not to the mechanism.
Does keeping the original track lose any quality? No. VideoLAN's support guide states it directly for the same-format case: VLC can provide the output "with no loss of quality, because there is no re-encoding of the content."
Can VLC keep the original track when converting to MP4?
The official muxer documentation does not cover MP4, so there is no documented list of the codecs it accepts — even though the same wiki uses mux="mp4" in its own examples. Run vlc -H to see what your build exposes, and check the official documentation rather than a third-party compatibility table.
Why did my converted file come out with no sound? Most likely the audio codec is not one your chosen container accepts. VideoLAN's documented behaviour there is that it "may silently fail" — you get a file, just not a complete one. Re-encode the audio to something the muxer takes, or pick a different container.
Is VLC always the right tool for this? Not necessarily, and VideoLAN says so. Writing specifically about audio-only sources, its support guide notes that "other tools may be even more powerful, faster, or more reliable for the task," adding: "Where VLC really shines is for sources which combine video and audio content." For the same idea elsewhere, see remuxing OBS recordings to MP4 and extracting audio without re-encoding in FFmpeg. More walkthroughs live in guides.
Quoted from VideoLAN's own wiki, checked 16 September 2026. The Transcode page carries VideoLAN's warning that it "is outdated and information might be incorrect" — verify anything version-specific with vlc -H on your own build.
