How to remove one track from video file using ffmpeg?
You are looking for -map
.
I have changed to using avconv
, but it should be about the same.
Let's say you have a file called "input.vob" with one video and two audio tracks; and you want to have "output.vob" with the video and the last audio.
You would do:
avconv -i input.vob -map 0:0 -c:v copy -map 0:2 -c:a copy output.vob
You should notice that:
- I did not copy
-map 0:1
- I did not need to do
-an
, because there are audio tracks. However, if there are no audio tracks at all, you may need to use such an attribute. - Sometimes the streams are not numbered in the way i've described, for example audio can come before video.
- If there are subtitle streams there, you need to figure out how to deal with them as well.
You cannot work on files "in place", you need to save into a different file.
P.S. You may want to ask such questions on video.stackexchange.com next time.
The most efficient method is to use negative mapping in the -map
option to exclude specific stream(s) ("tracks") while keeping all other streams.
Remove a specific audio stream / track
ffmpeg -i input -map 0 -map -0:a:2 -c copy output
-map 0
selects all streams from the input.-map -0:a:2
then deselects audio stream 3. The stream index starts counting from 0, so audio stream 10 would be0:a:9
.
Remove all audio streams / tracks
ffmpeg -i input -map 0 -map -0:a -c copy output
-map 0
selects all streams from the input.-map -0:a
then deselects all audio streams from the input.
Remove specific audio streams / tracks
Keep everything except audio streams #4 (at offset 3) and #7 (at offset 6):
ffmpeg -i input -map 0 -map -0:a:3 -map -0:a:6 -c copy output
Remove all subtitles and data
ffmpeg -i input -map 0 -map -0:s -map -0:d -c copy output
Only include video and audio
This example does not need to use any negative mapping.
ffmpeg -i input -map 0:v -map 0:a -c copy output
Removing other stream / track types
If you want to remove other stream types you can use the appropriate stream specifier.
v
- video, such as-map -0:v
a
- audio, such as-map -0:a
(as shown above)s
- subtitles, such as-map -0:s
d
- data, such as-map -0:d
t
- attachments, such as-map -0:t
Extract or remove a specific audio channel
Using a stereo input and channelsplit filter. Example to get the right channel only and output a mono audio file:
ffmpeg -i stereo.wav -filter_complex "[0:a]channelsplit=channel_layout=stereo:channels=FR[right]" -map "[right]" front_right.wav
channel_layout
is the channel layout of the input stream. The default isstereo
.channels
lists the channels to be extracted as separate output streams. The default isall
which extracts each input channel as a separate, individual stream.See
ffmpeg -layouts
for a list of accepted channel layouts (forchannel_layout
option) and channel names (forchannels
option).See FFmpeg Wiki: Audio Channels for more examples.
More info
-map
option documentation- FFmpeg Wiki: Map